Fact-checked by Grok 2 weeks ago

Powdery mildew

Powdery mildew is a common fungal disease affecting a wide array of plants, characterized by the appearance of white to gray, powdery fungal growth on the surfaces of leaves, stems, flowers, and sometimes fruits, caused by obligate biotrophic fungi in the order Erysiphales that require living host tissue for survival and reproduction.^[1]^[2]^[3] These fungi, belonging to genera such as Erysiphe, Golovinomyces, Podosphaera, and Blumeria, are highly specialized, with most species infecting only specific host plants, though collectively they impact thousands of angiosperm species including crops, ornamentals, and wild plants.^[1]^[2] The powdery appearance results from chains of asexual conidia produced on the surface of the host, which spread via wind and germinate without the need for free water, enabling infection in dry conditions.^[1]^[3] Symptoms typically begin as small white patches that expand to cover larger areas, leading to chlorosis (yellowing), necrosis, leaf distortion, premature defoliation, and reduced photosynthesis, which can significantly lower crop yields and aesthetic value in ornamental plants.^[1]^[3] Unlike downy mildews, powdery mildew fungi grow epiphytically on the plant surface without penetrating deeply into tissues, though they form haustoria to extract nutrients, creating localized "green islands" of sustained host vitality amid infection.^[2] The disease thrives in warm daytime temperatures (around 20–30°C or 68–86°F) with cooler nights and high relative humidity (above 95%), but low light and poor air circulation exacerbate outbreaks; it is particularly problematic in semi-arid regions and greenhouses.^[1]^[3] Economically, powdery mildew poses a major threat to agriculture, affecting key crops like cereals (Triticum aestivum, Hordeum vulgare), cucurbits (Cucumis sativus, Cucurbita spp.), peas (Pisum sativum), grapes, and roses, with global losses estimated in billions due to reduced productivity and the need for fungicide applications.^[2]^[3]^[4] Overwintering occurs through dormant sexual structures (chasmothecia) or mycelium in plant debris, with primary infections in spring leading to secondary spread via conidia throughout the growing season.^[1] Management relies on cultural practices like improving airflow, using resistant varieties, and targeted fungicides, while research focuses on host-pathogen interactions and biocontrol to mitigate its widespread impact.^[3]^[2]

Overview

Definition and characteristics

Powdery mildew refers to a group of plant diseases caused by obligate biotrophic fungi in the order Erysiphales of the phylum Ascomycota, characterized by the formation of conspicuous white, powdery mycelial growth on the surfaces of infected plant tissues such as leaves, stems, and fruits.^[5]^[6] These fungi cannot survive on dead plant material or in soil and rely entirely on living host plants for nutrients, making them highly host-specific pathogens that infect a wide range of angiosperms across agricultural, horticultural, and natural ecosystems.^[7] The disease manifests as superficial, effuse patches of fungal hyphae that give the affected areas a dusty, flour-like appearance, often leading to reduced photosynthesis and plant vigor.^[8] Key morphological features of powdery mildew fungi include their predominantly epiphytic mycelium, which spreads across the host surface without penetrating deeply into tissues, and specialized haustoria that form intracellularly within epidermal cells to absorb nutrients.^[8] Asexual reproduction occurs through chains or single conidia—hyaline, barrel-shaped spores—that serve as the primary means of dispersal via wind, enabling rapid epidemic spread under favorable conditions.^[9] In the sexual phase, fungi produce cleistothecia, closed, flask-shaped fruiting bodies containing asci and ascospores, which overwinter and facilitate long-distance dissemination when ejected or carried by rain splash.^[10] Unlike downy mildew, which is caused by oomycete pathogens that produce sporangia on the plant's lower surfaces and require free water for spore germination, powdery mildew develops externally on both leaf sides, enters host cells directly without using stomata, and thrives in warm, dry environments with high humidity at night.^[11]^[12] This superficial growth and environmental preference distinguish powdery mildew as a true fungal disease adapted to arid conditions, contrasting with the more invasive, moisture-dependent nature of downy mildew.^[13] Powdery mildew imposes substantial economic burdens globally by diminishing crop yields, quality, and market value in sectors like agriculture, horticulture, and forestry, with annual management costs exceeding hundreds of millions of dollars in major production regions such as California vineyards.^[14]^[15] For instance, in grape production alone, the disease can reduce fruit quality and necessitate intensive fungicide applications, highlighting its role as one of the most economically significant foliar pathogens.^[16]

Historical significance

Early observations of powdery mildew appear in ancient texts, with Theophrastus in the 4th century BCE describing symptoms such as white coatings on rose leaves in his work on plants, marking one of the earliest recorded recognitions of the disease.^[17] However, specific identification of powdery mildew as a fungal pathogen occurred much later, with formal taxonomic classification advancing in the 19th century through mycologists like Elias Magnus Fries, who in his Systema Mycologicum (1821–1832) described and named numerous species in the genus Erysiphe, establishing the foundational nomenclature for powdery mildews within the Ascomycota.^[18] These efforts shifted perceptions from vague "blights" to structured mycology, enabling targeted study. The pivotal historical event for grape powdery mildew (Erysiphe necator, formerly Uncinula necator) was its introduction to Europe from North America, first reported in England in 1845 and independently identified in France in 1847 by researchers like William Tucker and Miles Joseph Berkeley, who described it as a novel cryptogamic parasite devastating vineyards.^[19] This outbreak, paralleling the concurrent phylloxera crisis, triggered widespread viticulture decline across Europe in the mid-19th century and prompting empirical remedies like sulfur dusting—initially a folklore practice adapted from earlier uses on peaches in 1821.^[20] The epidemic underscored the vulnerability of European Vitis vinifera to exotic pathogens, accelerating the transition from traditional remedies to scientific pathology during the 1800s.^[21] Key contributions from figures like Heinrich Anton de Bary furthered this evolution; in 1863, he elucidated the life cycle of a powdery mildew species (Sphaerotheca castagnei), including the role of haustoria in nutrient absorption from host plants, solidifying fungi as causal agents of disease.^[22] By the 20th century, severe epidemics of cereal powdery mildews, such as Blumeria graminis on wheat, ravaged intensive cropping systems in Europe and North America, driving innovations in fungicide development like benzimidazoles in the 1960s, though early resistance emerged by 1969.^[23]^[24] These events highlighted the pathogen's economic impact, with losses exceeding 20% in untreated fields, and spurred integrated management strategies. Post-2000 genomic studies have revolutionized understanding, revealing extensive genetic diversity and evolutionary history; for instance, analyses of 172 B. graminis genomes traced its global spread along trade routes, uncovering ancient variants that inform resistance breeding.^[25] This molecular era builds on historical milestones, emphasizing powdery mildews' adaptive radiation from the Late Cretaceous onward.^[7]

Symptoms and Diagnosis

Visible symptoms

The primary visible symptom of powdery mildew infection is the appearance of white to gray powdery patches on the surfaces of leaves, stems, flowers, and fruits, consisting of fungal mycelium and conidia.^[26] These patches often develop on both the upper and lower leaf surfaces, though they are more prominent on the upper side in many hosts.^[27] The powdery growth gives the affected plant parts a dusty or flour-like coating, which can be easily rubbed off in early stages.^[28] As the infection progresses, the initial small, circular spots expand and coalesce into larger patches, leading to chlorosis (yellowing) of the surrounding leaf tissue.^[27] In severe infections, powdery mildew can cause chlorosis and necrosis of host tissue, though it primarily affects the surface without deep penetration.^[29] Infected leaves may curl upward or become distorted, particularly in warm, dry conditions, and severe infections can cause premature defoliation as leaves wither and drop.^[30] This reduces the plant's photosynthetic capacity, contributing to overall weakening. On fruits, symptoms include superficial russeting—a rough, brownish discoloration—or cracking of the skin, especially in crops like apples and cucurbits.^[31] Symptom expression varies by host plant and tissue age, with denser fungal growth typically observed on young, actively growing tissues such as new leaves and shoots, which are more susceptible due to thinner cuticles.^[32] On mature tissues, infections are less common and sparser. In conditions of high relative humidity, which favor the pathogen despite requiring dry leaf surfaces for spore germination, the powdery growth remains characteristic. Secondary effects of visible symptoms include stunted plant growth and significant yield reductions, with losses reaching up to 50% in severely affected susceptible crops like wheat or cucurbits.^[33] These impacts arise from impaired photosynthesis and resource allocation to infected areas, but the disease does not typically kill the host plant outright.^[34]

Diagnostic methods

Field diagnosis of powdery mildew typically begins with visual inspection for the characteristic white, powdery fungal growth on plant surfaces, such as leaves, stems, or fruits. This superficial mycelium and conidia can be confirmed using a simple rub-off test, where gently rubbing the affected area with a finger or tape transfers the powdery residue, distinguishing it from non-fungal coatings.^[8]^[35] For more precise field-level verification, microscopic examination is essential. Using a dissecting or compound microscope, diagnosticians observe conidiophores—specialized hyphae bearing chains or single conidia on the plant surface—and haustoria, which are intracellular feeding structures penetrating host epidermal cells. Clear tape pressed onto infected tissue can collect samples for slide preparation, allowing identification of fungal morphology without destroying the specimen.^[8] In laboratory settings, molecular methods like polymerase chain reaction (PCR) targeting the internal transcribed spacer (ITS) regions of ribosomal DNA provide species-specific identification with high sensitivity, detecting latent infections before symptoms appear. Quantitative real-time PCR (qPCR) further enables pathogen quantification, achieving detection limits as low as 1 pg/μL of fungal DNA.^[36] Serological assays, such as enzyme-linked immunosorbent assay (ELISA), detect specific fungal antigens in plant extracts, offering rapid results though requiring specialized equipment.^[37] Advanced diagnostic tools enhance resolution and early detection. Transmission or scanning electron microscopy reveals ultrastructural details, such as conidial surface wrinkles or haustorial interactions with host cells, aiding taxonomic confirmation in research contexts. Hyperspectral imaging, using wavelengths from 400–1000 nm, non-invasively detects early infection (3–6 days post-inoculation) through spectral changes in reflectance, with partial least squares models achieving over 82% accuracy in severity assessment.^[38]^[39] Challenges in diagnosis include differentiating powdery mildew from similar white coatings caused by pests like mealybugs, which produce waxy secretions and may be accompanied by honeydew or sooty mold, unlike the uniform fungal powder. Molecular methods like PCR provide high accuracy for species identification, though amplification failures can occur in some taxa due to sequence variability.^[40]^[41]

Causative Agents

Taxonomy

Powdery mildew fungi belong to the phylum Ascomycota, class Leotiomycetes, order Erysiphales, and primarily the family Erysiphaceae, which encompasses over 900 species distributed across 19 genera.^[42] These obligate biotrophic fungi form a monophyletic clade within the Ascomycota, characterized by their unique ectoparasitic lifestyle and production of superficial mycelia.^[43] The family Erysiphaceae is the sole family in the order Erysiphales, with all known powdery mildew species classified therein following extensive taxonomic revisions. Among the key genera, Erysiphe represents the largest, comprising more than 50% of the species (approximately 450) with a broad taxonomic scope that has incorporated former genera such as Microsphaera and Uncinula through emendation.^[42] Blumeria is notable for its specialized adaptation, encompassing species primarily on grasses, while Podosphaera includes taxa on rosaceous plants, and the former Uncinula (now synonymous with Erysiphe) features species on grapes. Other significant genera include Golovinomyces, Phyllactinia, and Sawadaea, contributing to the family's diversity through distinct morphological traits in their anamorphic and teleomorphic stages. Phylogenetic studies, particularly those utilizing nuclear ribosomal DNA sequences such as 18S rDNA and internal transcribed spacer (ITS) regions, have confirmed the monophyly of the Erysiphales and delineated its internal structure into major lineages.^[44] Early molecular analyses divided the order into subgroups I-IV based primarily on variations in ascocarp (chasmothecial) appendages and conidial morphology, with subsequent refinements identifying five principal clades corresponding to traditional tribes: Erysipheae (lacking appendages), Microsphaereae (with mycelioid appendages), Uncinuleae (with uncinate appendages), Cystotheceae (with bullate basal appendages), and Phyllactinieae (with rigid, dichotomously branched appendages). These subdivisions highlight convergent evolution in appendage simplification and underscore the order's ancient divergence, estimated at around 76 million years ago.^[44] The nomenclature of powdery mildews traces back to Linnaean beginnings, with the first binomial name, Mucor erysiphe L. (1753), later reassigned to Phyllactinia guttata based on Linnaeus's description in Species Plantarum. Early classifications relied on morphological features like ascocarp appendages, as detailed in monographs by Salmon (1900) and Braun (1987), which recognized about 515 species. Post-1990s molecular phylogenetics revolutionized the field, leading to generic recircumscriptions—such as the expansion of Erysiphe and establishment of new genera like Neoerysiphe—and a comprehensive update in Braun and Cook's 2012 monograph, which cataloged approximately 820 species. Recent multi-locus phylogenetic studies (2024-2025) continue to describe new species and refine classifications, such as in the ongoing series on Erysiphe and Podosphaera lineages.^[45] Ongoing revisions, incorporating multi-locus data, continue to refine this framework, emphasizing the integration of morphological and genetic evidence.^[45]

Diversity of species

Powdery mildew fungi encompass over 900 described species in the family Erysiphaceae, all obligate biotrophs that cannot be cultured on artificial media and rely entirely on living host plants for growth and reproduction.^[42] These species demonstrate remarkable diversity in host specificity, with roughly 700 infecting dicotyledonous hosts—such as those in the Asteraceae, Fabaceae, and Vitaceae families—and about 150 targeting monocotyledonous plants, primarily in the Poaceae.^[46] This distribution underscores their evolutionary adaptations to diverse plant lineages, enabling colonization of over 10,000 angiosperm species worldwide while maintaining narrow ecological niches in most cases.^[47] A key aspect of their diversity lies in varying degrees of host range adaptation, ranging from monophagous species restricted to single host genera or families to polyphagous ones capable of infecting multiple plant families. For instance, Blumeria graminis, a monophagous pathogen, primarily infects cereal crops within the Poaceae family, with distinct formae speciales adapted to specific hosts like barley (f. sp. hordei) or wheat (f. sp. tritici).^[43] In contrast, Golovinomyces cichoracearum exhibits polyphagous behavior, infecting hosts across families including Asteraceae, Solanaceae, and Cucurbitaceae, which facilitates broader dispersal and adaptation to varied environments.^[48] Notable examples include Erysiphe necator, which specifically targets grapevines (Vitis spp.) in the Vitaceae, causing significant economic losses in viticulture; Podosphaera mors-uvae (formerly Sphaerotheca mors-uvae), a specialist on strawberries (Fragaria spp.) and other Rosaceae; and Erysiphe diffusa (formerly Microsphaera diffusa), which affects sunflowers (Helianthus spp.) and other Asteraceae. These adaptations highlight how species-level traits, such as conidial morphology and germination patterns, align with host physiology and environmental conditions.^[49] Genetic diversity within powdery mildew species further enhances their adaptability, driven by intraspecific variation in mating types that regulate sexual recombination and generate novel genotypes.^[50] Post-2010 genomic studies have illuminated this variation, revealing mosaic genome structures with expanded gene families encoding effectors and virulence factors; for example, sequencing of Blumeria graminis genomes has mapped avirulence genes linked to host recognition and mapped quantitative trait loci for aggressiveness.^[50] Similarly, analyses of Golovinomyces spp. have identified polymorphisms in mating-type idiomorphs (MAT1-1 and MAT1-2) that promote genetic exchange, contributing to rapid evolution of virulence under selection pressure from resistant hosts.^[51] Such insights from high-throughput sequencing underscore the role of genomic plasticity in sustaining species diversity and pathogenicity across powdery mildews.^[52]

Life Cycle

Infection process

The infection process of powdery mildew begins when wind-dispersed conidia land on a susceptible host plant surface, such as leaves or stems. These asexual spores adhere to the host cuticle and germinate rapidly under high relative humidity (above 85%) but without requiring free water, typically within 2-4 hours at optimal temperatures of 15-25°C.^[53] Germination involves the emergence of a primary germ tube, followed by a secondary germ tube that differentiates into an appressorium within 6-12 hours, which generates turgor pressure to facilitate penetration.^[54] Penetration occurs directly through the host epidermal cell wall via a penetration peg from the appressorium, usually within 24-48 hours post-inoculation, without killing the host cells.^[53] Inside the host cell, the fungus forms haustoria—specialized feeding structures that invaginate the plant plasma membrane and absorb nutrients—typically within 24-48 hours of penetration. Following successful penetration, superficial mycelium spreads across the host surface, colonizing epidermal cells while remaining ectoparasitic, enabling nutrient uptake and colony expansion without deep tissue invasion.^[53] The latency period, from conidial inoculation to the appearance of visible symptoms like white mycelial patches, lasts 3-7 days under favorable conditions of 15-25°C and high humidity. During this asymptomatic phase, the fungus establishes and multiplies internally before external growth becomes evident. Dispersal primarily occurs through wind-blown conidia released from mature colonies, capable of traveling up to several kilometers to initiate secondary infections on nearby or distant hosts.^[55] Local spread can also happen via air currents or mechanical means, but long-distance dissemination relies on favorable wind patterns.^[56]

Reproduction

Powdery mildew fungi primarily reproduce asexually during the growing season, producing conidia in chains at the tips of specialized hyphae called conidiophores that emerge from the surface mycelium. These conidia, typically barrel- or oval-shaped, are released in large numbers and dispersed by wind, enabling rapid colonization of nearby host tissues under favorable conditions. Each conidiophore can generate 1-2 conidia per day per hypha, with production optimized in warm (15–25°C) and dry weather that promotes quick germination and infection without free water.^[57]^[58]^[15] Sexual reproduction occurs later in the season when hyphae of opposite mating types (MAT1-1 and MAT2-1) fuse, forming an ascogonium and antheridium that develop into dikaryotic hyphae. These structures mature into cleistothecia, compact, spherical fruiting bodies containing multiple asci filled with ascospores, which serve as durable overwintering propagules. Cleistothecia formation is triggered by environmental cues such as shortening day lengths and cooling temperatures (below 15°C) in late summer or fall, allowing the fungus to survive adverse winter conditions.^[59]^[58]^[60] The reproductive cycle of powdery mildew is polycyclic, with multiple overlapping generations occurring within a single growing season due to the short latent period (3–7 days) from conidial germination to new spore production. In temperate regions with extended warm periods, 10–20 cycles can occur, amplifying epidemic potential through repeated asexual dissemination. Mating type compatibility (one MAT1-1 and one MAT2-1 per cleistothecium) ensures genetic recombination during the sexual phase, enhancing adaptability.^[15]^[61] While most powdery mildew species exhibit both reproductive modes, variation exists; for instance, some populations of Blumeria graminis f. sp. hordei in warmer or tropical regions may lack a functional sexual stage, relying solely on asexual conidia for persistence and spread.^[62]^[63]

DNA repair

Powdery mildew fungi, as obligate biotrophs, rely on robust DNA repair mechanisms to counteract damage from environmental stressors like ultraviolet (UV) radiation and reactive oxygen species (ROS) generated by host plants during infection. These pathways ensure genomic stability, supporting survival, reproduction, and pathogenesis in nutrient-limited intracellular environments. Primary mechanisms include nucleotide excision repair (NER) for UV-induced lesions, homologous recombination (HR) for accurate repair during meiosis, and non-homologous end joining (NHEJ) for rapid ligation of double-strand breaks (DSBs). Photolyase-mediated repair, a light-dependent variant of NER, plays a prominent role in repairing cyclobutane pyrimidine dimers (CPDs) caused by UV exposure.^[64]^[65] In the tomato powdery mildew pathogen Pseudoidium neolycopersici, NER and photolyase activity enable conidial recovery from UV-C damage (254 nm), with the photolyase gene PnPHR1 (a class I CPD photolyase) upregulated within 4 hours post-exposure. This enzyme, binding flavin adenine dinucleotide (FAD) and methenyltetrahydrofolate (MTHF) cofactors, uses blue/UV-A light (365–454 nm) to split dimers, restoring spore viability and infection potential. HR facilitates precise DSB repair using homologous templates, essential during meiotic recombination for generating genetic diversity in ascospores, while NHEJ provides error-prone but fast closure of breaks, often leading to insertions or deletions. These pathways are conserved in ascomycete fungi, including powdery mildews, though obligate parasitism correlates with relaxed selection on some repair components. Environmental triggers like UV irradiation activate photolyase, while host-derived ROS during haustorial penetration likely induce HR and NHEJ to mitigate oxidative DSBs.^[64]^[66]^[65] Genomic studies between 2015 and 2020 on Erysiphe necator, the causal agent of grape powdery mildew, identified over 20 core DNA repair genes, but revealed extensive losses in mismatch repair (MMR) components, with E. necator lacking nine MMR genes such as MLH3, EXO1, and PMS2. Similar losses occur in other powdery mildews, like 21 in Erysiphe pisi and five in Blumeria graminis, leading to elevated mutation rates, longer microsatellites, and an A|T bias. These deficiencies impair post-replication error correction but enhance adaptability in stable host niches. In pathogenesis, efficient repair supports haustorial development under ROS stress, with incomplete repair fostering genomic variability that boosts virulence evolution; for instance, MMR losses correlate with accelerated sequence divergence, potentially reducing individual virulence by increasing instability but enabling population-level gains in host adaptation.^[67]^[68] The proficiency of these repair systems, coupled with tolerated gene losses, underpins the rapid emergence of fungicide resistance in powdery mildews. Elevated mutation rates from MMR deficits facilitate adaptive variants against demethylation inhibitors (DMIs) and quinone outside inhibitors (QoIs), as seen in diverse E. necator populations. This mutational hypervariability, rather than hyper-repair, drives resilience, highlighting DNA repair's dual role in maintaining core functions while permitting evolutionary flexibility for pathogen persistence.^[67]^[69]

Environmental Factors

Conditions promoting disease

Powdery mildew fungi exhibit optimal development within moderate temperature ranges, with spore germination and infection most efficient at 20–26°C. Disease progression is significantly inhibited below 10°C, where germination is minimal, and above 35°C, which can arrest fungal growth or kill spores. These temperature preferences align with spring and fall conditions in many temperate zones, allowing multiple infection cycles during favorable weather periods.^[70]^[71]^[72] Unlike water-dependent pathogens such as those causing downy mildew, powdery mildew requires high relative humidity (70–95%) for initial infection and conidial germination but favors dry foliar surfaces and low humidity during the day for sporulation and dispersal. Nighttime high humidity, often exceeding 90%, combined with daytime dryness, creates ideal microclimates that enhance pathogen survival and spread without free water, which actually inhibits spore germination. This humidity dynamic contrasts sharply with obligately wet-loving fungi, enabling powdery mildew to thrive in arid or semi-arid environments where other diseases falter.^[70]^[73]^[71] Additional abiotic factors amplify disease risk, including moderate to low light levels that favor fungal growth in shaded areas, as ultraviolet light suppresses sporulation. Poor air circulation within dense plant canopies traps humidity and reduces spore dispersal barriers, promoting localized epidemics. Elevated soil nitrogen from excessive fertilization boosts host susceptibility by stimulating lush, tender growth that serves as a preferred substrate for infection.^[73]^[74]^[75] Climate change exacerbates these conditions; a modeling study on winter wheat in China projected that warmer temperatures and shifting humidity patterns could increase powdery mildew epidemics by approximately 13–14% (with ranges up to 21%) by the 2050s under various climate scenarios, particularly through extended periods of favorable nighttime warmth that align with infection windows. Such shifts may intensify outbreaks in susceptible crops like wheat, where historical data already link rising temperatures to higher disease incidence.^[76] As of 2025, new host records continue to expand the documented range, with 29 additional records reported in Taiwan, highlighting ongoing discoveries in pathogen-host interactions.^[77]

Host range and susceptibility

Powdery mildew fungi exhibit an exceptionally broad host range, infecting more than 10,000 species of angiosperms across numerous plant families, including economically important groups such as Rosaceae, Vitaceae, Poaceae, and Solanaceae.^[43] This diversity encompasses both herbaceous and woody plants, with some fungal species showing high specificity limited to a single genus or family, while others display wider adaptability across multiple families.^[15] No gymnosperms are known hosts for these pathogens.^[15] Susceptibility to powdery mildew infection is influenced by several host plant factors, with young, actively growing tissues such as emerging leaves and buds being particularly vulnerable due to their thinner cell walls and delayed defense responses.^[4] Genetic traits also play a key role; for instance, the Mildew Locus O (MLO) genes in susceptible hosts facilitate fungal penetration by regulating cellular processes like vesicle trafficking and calcium signaling, thereby promoting infection.^[4] In non-susceptible or resistant plants, pre-formed physical barriers, such as waxy cuticles or surface structures, can impede initial spore germination and appressorial formation.^[4] Post-invasion resistance mechanisms further contribute to host variability, including the rapid deposition of callose—a β-1,3-glucan polymer—in papillae at penetration sites, which reinforces cell walls and halts hyphal advancement.^[78] Elevated early callose accumulation has been shown to confer complete penetration resistance in certain interactions.^[79] These defenses, along with hypersensitive cell death and pattern-triggered immunity, effectively limit powdery mildew establishment in non-host plants.^[4] Powdery mildew fungi are cosmopolitan in distribution, occurring worldwide on susceptible angiosperms, with highest species diversity reported in the Northern Hemisphere, particularly in regions like Southeast Asia.^[43] Endemic species are noted in tropical areas, and the pathogens' spread via ornamental plants has led to quarantine concerns, as new host associations can introduce them to previously unaffected regions.^[80]

Management Strategies

Cultural practices

Cultural practices are essential non-chemical strategies for preventing and managing powdery mildew by reducing inoculum sources, improving environmental conditions, and enabling timely interventions at the farm level. These methods focus on agronomic adjustments that disrupt the pathogen's life cycle and limit its spread across various hosts like vegetables, fruits, and ornamentals. Sanitation plays a critical role in minimizing overwintering spores and secondary infections. Removing and destroying infected plant debris, such as fallen leaves and pruned shoots, prevents the buildup of inoculum that can initiate new infections in subsequent seasons. Pruning excess or infected foliage during the dormant period or early in the growing season enhances air circulation, reducing the humid microclimates favored by the fungus. Proper plant spacing, guided by the mature size of the crop, further promotes airflow and sunlight penetration, decreasing relative humidity around foliage and lowering disease incidence by up to 30-50% in well-managed orchards and fields. Timing of cultural activities is key to avoiding conditions that exacerbate powdery mildew. Overhead irrigation should be avoided or timed for mid-morning to allow foliage to dry quickly, as prolonged leaf wetness, though not required for infection, can indirectly favor spore dispersal in humid environments. Planting in full sun and during optimal seasons with lower disease pressure, combined with mulching to regulate soil moisture and support plant vigor without creating excess humidity, helps suppress early-season outbreaks. Crop rotation with non-host plants breaks the pathogen's life cycle by eliminating continuous sources of inoculum over multiple seasons. Regular monitoring through weekly field scouting allows growers to detect early symptoms, such as small white powdery spots on leaves, enabling proactive management before widespread infection occurs. Action thresholds vary by crop but often include intervention at the first sign of disease or when 1 in 50 older leaves shows symptoms in susceptible vegetables like cucurbits. Integrated cultural approaches, combining sanitation, spacing, rotation, and monitoring, can provide substantial yield protection, with reductions in disease severity leading to 20-40% less yield loss in low-pressure areas when implemented consistently.

Chemical controls

Chemical controls for powdery mildew primarily involve fungicides that act as protectants or systemics, targeting the fungal pathogen's growth and reproduction on host plants. Sulfur-based fungicides, used since the mid-19th century, serve as contact protectants that prevent spore germination by disrupting fungal metabolism through multi-site action.^[81] These compounds achieve 70-90% efficacy in field trials against various powdery mildew species, particularly on grapes and cucurbits, when applied preventively.^[82] Systemic triazoles, such as tebuconazole, represent a key class of demethylation inhibitors (DMIs) that block ergosterol biosynthesis in fungal cell membranes, halting pathogen development post-infection.^[83] These provide curative and protective effects with efficacies often exceeding 85% on cereals and fruits when applied early.^[84] Non-conventional options include mineral-based agents like potassium bicarbonate, a contact fungicide approved for organic use that raises pH to disrupt fungal cell walls and kill spores rapidly upon contact.^[26] Horticultural and neem oils function by smothering spores and interfering with membrane integrity, offering moderate control (50-70% efficacy) as supplements in low-pressure scenarios.^[85] To mitigate resistance, rotation among fungicide classes—such as alternating DMIs with multi-site protectants like sulfur—is recommended, as single-mode agents like QoI fungicides have shown widespread resistance in over 50% of field isolates by 2020.^[69]^[86] Foliar applications of these chemicals occur at 7- to 14-day intervals, starting before symptom onset and integrated within IPM programs to minimize usage.^[87] Regulatory restrictions, such as EU measures tightening approvals for certain DMIs due to endocrine disruption concerns since 2010, have prompted shifts toward lower-risk alternatives.^[88] Environmental challenges include toxicity to pollinators; for instance, DMIs like myclobutanil impair bee flight muscles at sublethal doses, and as of 2025, studies show synergistic midgut toxicity when combined with insecticides like broflanilide, underscoring the need for targeted applications to avoid non-target impacts.^[89]^[90]

Biological controls

Biological controls for powdery mildew involve the use of living organisms as natural enemies to suppress the fungal pathogen, offering an environmentally friendly alternative to synthetic fungicides. These agents include hyperparasites, predators, and antagonistic microbes that target the powdery mildew mycelium, spores, or reproductive structures directly or indirectly through competition and induced plant defenses.^[91] Hyperparasitic fungi, such as Ampelomyces quisqualis, are among the most studied biocontrol agents, parasitizing the mycelium of powdery mildew fungi and significantly reducing conidial production. A. quisqualis infects powdery mildew hyphae intracellularly, colonizing up to 80% of the host's conidiophores and thereby limiting spore dispersal by degrading the pathogen's cellular structure. Commercial formulations like AQ10, based on A. quisqualis strain CNCM I-807, have been developed for foliar application and demonstrate efficacy against powdery mildews on crops such as grapes and cucumbers.^[92]^[93]^[94] Predatory arthropods also contribute to control by consuming powdery mildew spores and mycelium. Certain mites, including iolinid species like Pronematus spp., actively feed on fungal structures, suppressing infection levels in greenhouse settings. Similarly, insects such as the lady beetle Psyllobora vigintimaculata (Coleoptera: Coccinellidae) graze on conidia and hyphae, with larvae capable of consuming thousands of spores daily, providing notable reductions in disease severity on cucurbits and ornamentals.^[95]^[96] Antagonistic bacteria, exemplified by Bacillus subtilis, exert control through the production of antifungal compounds such as lipopeptides and enzymes that inhibit powdery mildew growth. Strains like B. subtilis UMAF6639 colonize leaf surfaces, outcompeting the pathogen for nutrients and space while triggering systemic resistance in hosts like cucumber. Field applications of B. subtilis-based products have shown compatible integration with other controls.^[97]^[98] The primary mechanisms of these biocontrol agents include mycoparasitism, where hyperparasites like A. quisqualis secrete cell wall-degrading enzymes such as chitinases and proteases to penetrate and lyse host hyphae, and nutrient competition, as seen with Bacillus spp. that produce siderophores to limit iron availability to the fungus. Predators employ direct consumption, reducing viable inoculum. In greenhouse and field trials, these agents have achieved 50-70% disease control on crops like strawberries and grapes, particularly when applied preventively.^[91]^[99]^[100] Recent advances in the 2020s emphasize endophytic microbes for enhanced sustainability, with strains like Bacillus amyloliquefaciens YN201732 colonizing plant tissues internally to provide long-term protection against powdery mildew via induced systemic resistance and direct antagonism. As of 2025, studies demonstrate the efficacy of incorporating biofungicides into fungicide rotations for powdery mildew control in vineyards, achieving consistent reductions over multiple years (2023-2024) when alternated with conventional programs. These approaches are increasingly integrated into integrated pest management (IPM) programs, combining biocontrol with cultural practices to minimize chemical inputs and promote ecological balance in agriculture.^[101]^[102]^[103]

Genetic resistance

Genetic resistance to powdery mildew in plants is categorized into qualitative and quantitative types, with qualitative resistance mediated by single dominant R-genes that confer race-specific, vertical resistance, often leading to hypersensitive responses that halt pathogen growth early.^[104] In contrast, quantitative resistance involves multiple polygenic loci contributing to partial, race-non-specific horizontal resistance, which is generally more durable due to its additive effects and lower likelihood of being overcome by pathogen evolution.^[105] A prominent example of qualitative resistance is the Mla locus in barley, where alleles like Mla6 encode nucleotide-binding leucine-rich repeat (NLR) receptors that recognize specific avirulence effectors from the pathogen Blumeria graminis f. sp. hordei, triggering immunity.^[106] Breeding strategies for powdery mildew resistance leverage marker-assisted selection (MAS) to introgress quantitative trait loci (QTLs), such as the Ren1 locus in grapevines (Vitis vinifera), which provides partial resistance by limiting hyphal proliferation and sporulation through a cluster of resistance gene analogs.^[107] Since 2015, CRISPR/Cas9 editing has enabled precise insertion or modification of R-genes, as demonstrated in tomato where knockout of the susceptibility gene SlMLO1 generated non-transgenic resistant lines, and in grapevines where dual editing of MLO6 and MLO7 homologs enhanced resistance without yield penalties.^[108] Similar applications in cucumber have targeted Pm0 loci to produce transgene-free varieties with broad-spectrum resistance.^[109] As of 2024, CRISPR/Cas9-driven double modification of grapevine MLO6-7 and NPR3 genes has imparted enhanced resistance to both powdery and downy mildew.^[110] Notable examples include grape cultivars like 'Kishmish vatkana' and 'Dzhandzhal kara' harboring the Ren1 locus, which have been used in breeding programs to develop partially resistant hybrids, though monogenic qualitative resistances like those at Mla can be rapidly overcome by pathogen adaptation, necessitating pyramiding with quantitative traits for longevity.^[111] Such genetic approaches yield 20-50% improvements in yield stability by mitigating infection-related losses, as seen in resistant lines that maintain productivity under moderate disease pressure.^[112] Global breeding programs, such as those at the International Maize and Wheat Improvement Center (CIMMYT), incorporate wild relatives like Dasypyrum villosum to transfer durable resistance genes (e.g., Pm21) into elite cereal germplasm, enhancing polygenic backgrounds for sustainable control.^[113]

Impacts on Specific Hosts

Cereals

Powdery mildew affects major cereal crops such as wheat, barley, oats, and rye, primarily caused by the obligate biotrophic fungus Blumeria graminis and its host-specific formae speciales.^[114] The most economically significant pathogens are B. graminis f. sp. tritici on wheat and triticale, and f. sp. hordei on barley, with additional formae speciales like f. sp. avenae for oats and f. sp. secalis for rye, each adapted to specific cereal hosts within the Poaceae family.^[115] These pathogens thrive in temperate climates, where cool, humid conditions favor spore germination and infection, leading to epidemics that can reduce yields by 10-40% in susceptible varieties during severe outbreaks.^[53] Symptoms typically begin as small, white, powdery patches of mycelium and conidia on the upper surfaces of young leaves, spreading to cover extensive areas of foliage, stems, and occasionally heads as the disease progresses.^[116] This dense fungal growth interferes with photosynthesis and nutrient uptake, weakening plants and causing chlorosis, premature senescence, and reduced tillering; severe infections can lead to stem lodging due to compromised structural integrity and kernel shriveling from diminished assimilate allocation to developing grains.^[117] Historical epidemics in Europe during the 1970s, particularly in the Netherlands and surrounding regions, highlighted the disease's destructive potential, with widespread infections in winter wheat and barley fields driven by favorable weather and susceptible cultivars, resulting in substantial yield reductions across the continent.^[118] It can lead to estimated annual yield losses of 7.6–19.9% in wheat, underscoring its role as a persistent threat to food security in temperate grain-growing areas.^[25] Management of powdery mildew in cereals relies on integrated approaches tailored to host-specific pathogens, including the deployment of resistant varieties such as the barley cultivar Pallas, which carries the mlo resistance gene for broad-spectrum, durable protection against B. graminis f. sp. hordei.^[119] Chemical controls, particularly strobilurin (QoI) fungicides like azoxystrobin, provide effective preventive and curative action by inhibiting mitochondrial respiration in the fungus, often applied at key growth stages to suppress epidemics in wheat and barley.^[120] Climate change is altering disease dynamics, with warmer winters in temperate zones potentially enhancing overwintering survival of B. graminis ascospores on volunteer plants and debris, thereby increasing primary inoculum and extending epidemic risks into new regions.^[76]

Grapes

Powdery mildew of grapes is caused by the obligate biotrophic fungus Erysiphe necator (synonym Uncinula necator), which primarily infects green tissues such as leaves, shoots, and berries, leading to the characteristic white, powdery fungal growth on the surfaces.^[27] The pathogen penetrates host cells via haustoria, disrupting photosynthesis and nutrient allocation, which can result in defoliation, reduced berry size, and skin cracking on fruits. In severe cases, infections cause yield losses of 20-30% by impairing fruit set and ripening, while also predisposing berries to secondary infections like bunch rot from Botrytis cinerea.^[121]^[122] Historically, E. necator devastated European vineyards starting in the 1840s, with widespread epidemics by the 1850s that threatened the industry's survival until sulfur was found effective against it around 1845, based on earlier observations in peach orchards. This led to the widespread adoption of sulfur dusting and spraying, marking one of the earliest large-scale uses of chemical control in agriculture. The disease's arrival, likely from North America via imported plant material, facilitated bunch rot outbreaks by weakening berry integrity, exacerbating losses during humid post-infection periods.^[24]^[20] Beyond yield reduction, powdery mildew significantly degrades wine quality by altering berry composition, imparting off-flavors such as bitter, musty, or mushroom-like notes due to fungal metabolites and impaired sugar accumulation. Management in viticulture emphasizes canopy management practices, such as leaf removal and shoot positioning, to enhance airflow and UV exposure, thereby suppressing spore germination. Chemical controls include demethylation inhibitor (DMI) fungicides like myclobutanil, which target ergosterol biosynthesis in the fungus, often applied preventively in rotation to mitigate resistance. Breeding efforts incorporate resistance genes, such as Run1 from Muscadinia rotundifolia, into rootstocks and scions to provide durable protection without relying solely on sprays.^[123]^[124]^[27]^[125]^[126] Powdery mildew is a widespread disease affecting vineyards globally, with most Vitis vinifera cultivars being highly susceptible, posing particular challenges for organic production in humid regions where sulfur efficacy diminishes under prolonged moisture, necessitating integrated approaches like biological agents and predictive modeling.^[16]^[127]^[128]

Legumes

Powdery mildew affects a range of legume crops, including food legumes such as beans, peas, chickpeas, and soybeans, as well as forage legumes like alfalfa. In beans and peas, the primary pathogen is Erysiphe polygoni (syn. Microsphaera diffusa for some hosts), which produces white, powdery fungal growth on leaves, stems, and pods, leading to chlorosis, premature leaf drop, and reduced photosynthesis.^[129]^[130] For chickpeas, Leveillula taurica is the main causal agent, causing internal mycelial growth and external conidial production that results in yellowing, necrosis, and defoliation, particularly under warm, dry conditions.^[131] Severe infections across these hosts can lead to defoliation, which disrupts pod development and reduces pod set by up to 20-30% in susceptible varieties, as seen in field studies on peas and beans where early-season infection shortened the reproductive phase.^[132]^[133] Key legume crops experience notable production losses from powdery mildew. In soybeans (Glycine max), the disease, primarily caused by Microsphaera diffusa, emerges in mid- to late season and can cause up to 10% yield reduction in the United States through defoliation and decreased seed fill, especially in susceptible cultivars under dense canopies.^[134]^[135] Alfalfa (Medicago sativa), a major forage legume, suffers from powdery mildew caused by Erysiphe baeumleri or related species, resulting in reduced leaf retention, lower forage yield, and declined nutritional quality due to increased fiber content and decreased protein levels from repeated defoliation.^[136] In chickpeas (Cicer arietinum), L. taurica infections can reduce yields by 20-40% in severe cases by limiting pod formation and increasing susceptibility to secondary pathogens.^[137] The disease is particularly severe in warm, dry subtropical regions, where high daytime temperatures (25-35°C) and low humidity favor spore dispersal without needing free water, as observed in chickpea and bean fields in tropical and subtropical climates.^[129]^[87] Integrated management emphasizes varietal resistance; for example, soybean lines derived from resistant germplasm like PI 230970 exhibit partial resistance through delayed symptom development and reduced spore production, combined with cultural practices such as crop rotation and avoiding overhead irrigation.^[138] Economic impacts are significant for these protein-rich crops, with global losses estimated in millions of dollars annually due to reduced seed quality and yield; post-2010, breakdowns in single-gene resistances (e.g., er loci in peas) have prompted shifts toward pyramided resistance strategies to counter evolving pathogen races.^[139]^[112]

Vegetables (onions, squashes, strawberries)

Powdery mildew on onions is primarily caused by the fungus Leveillula taurica, which produces white to pale yellow lesions on older leaves that develop into powdery growth, reducing photosynthesis and potentially leading to smaller bulb sizes.^[140] Severe infections can result in yield losses of up to 20%, particularly when the disease develops early in the season.^[34] The pathogen thrives in dry, warm conditions with high relative humidity at night, allowing spores to spread via wind to nearby susceptible hosts.^[141] In squashes and other cucurbits, Podosphaera xanthii (synonym Podosphaera fusca) is the main causal agent, manifesting as white powdery spots on leaves, stems, and fruits that coalesce to cover plant surfaces.^[142] Infections on fruits lead to russeting—a rough, brownish discoloration of the skin—that significantly reduces marketability by up to 30%, as affected produce is less appealing for fresh consumption.^[143] Overall yield declines occur due to premature leaf senescence, smaller fruit size, and delayed ripening, with losses potentially reaching 20% or more in unmanaged fields.^[142] Strawberry powdery mildew, incited by Podosphaera aphanis, affects leaves, flowers, fruits, and runners, producing a characteristic white, felt-like growth on the undersides of leaves and causing upward curling and reddish blotches.^[144] Fruit infections result in scarring and deformation, rendering berries unmarketable and contributing to yield reductions of 15-50% in severe outbreaks, especially under humid, moderate-temperature conditions (15-27°C).^[144] Runner infections are particularly problematic, as the fungus spreads systemically through propagation material, perpetuating the disease in new plantings.^[145] Day-neutral varieties, such as 'Seascape' and 'Albion', exhibit heightened susceptibility compared to short-day types, necessitating vigilant monitoring during extended production cycles.^[146] Management of powdery mildew across these vegetables relies on preventive applications of sulfur-based products, including dusts and wettable powders, which are effective when initiated before symptoms appear and repeated at 7-10 day intervals.^[87] For strawberries, emphasis on day-neutral varieties involves integrating sulfur with cultural practices like improved air circulation to mitigate runner propagation of the pathogen.^[147]

Fruits (apples, pears)

Powdery mildew on pome fruits such as apples and pears is primarily caused by the fungal pathogen Podosphaera leucotricha, an obligate biotroph that infects buds, leaves, shoots, blossoms, and fruit.^[148]^[149] The fungus overwinters as mycelium within dormant buds, with primary infections emerging in spring on young tissues, where conidia are produced and dispersed by wind to initiate secondary infections under warm (50–77°F) and humid conditions.^[148]^[150] This cycle is particularly severe in humid orchard environments, such as those near water bodies, where prolonged leaf wetness and high humidity favor rapid spread during the growing season.^[148]^[149] Bud infections by P. leucotricha lead to stunted shoot growth and dwarfing, while blossom and fruit infections result in russeting, characterized by net-like scars on the skin, potentially causing 10–20% yield losses in susceptible cultivars.^[148]^[149] Overall, the disease reduces tree vigor and winter hardiness, contributing to irregular fruit set and biennial bearing patterns, as infected buds open later and fail to support consistent production.^[150]^[149] Historically, powdery mildew has posed significant challenges to U.S. cider apple production, where traditional heirloom varieties are highly susceptible, exacerbating orchard management issues in eastern regions.^[148] Management in apple and pear orchards emphasizes early-season interventions, such as applications of lime sulfur at the tight cluster stage to suppress overwintering inoculum and prevent initial infections.^[150]^[151] Planting resistant cultivars, including Liberty apple, which exhibits moderate to high resistance to P. leucotricha, is a key genetic strategy to minimize disease pressure and reduce reliance on chemical controls.^[152]^[153] Pears are similarly susceptible, often requiring integrated approaches to limit inoculum from nearby apple trees.^[154]

Ornamentals (Syringa, Acer, Berberis)

Powdery mildew infections on ornamental plants such as lilac (Syringa spp.), maple (Acer spp.), and barberry (Berberis spp.) primarily cause aesthetic damage, reducing their visual appeal in landscapes and gardens where appearance is paramount.^[155] These woody ornamentals are commonly used in hedges, borders, and specimen plantings, making visible symptoms like white fungal coatings particularly detrimental to their ornamental value. The disease thrives in conditions of high humidity with moderate temperatures, often appearing in late summer and spreading via airborne spores, which can introduce infections through nursery stock traded across regions.^[156] On lilac (Syringa spp.), powdery mildew is primarily caused by Erysiphe syringae, resulting in a white, mealy fungal growth on leaf surfaces that distorts foliage and creates an unsightly appearance in landscape settings.^[157] This pathogen favors cool nights and warm days with high humidity, leading to infections that, while rarely lethal, mar the plant's elegance during its blooming period and into fall.^[158] In western North America, E. syringae co-occurs with related species like Phyllactinia syringae, exacerbating the cosmetic impact on cultivated varieties.^[159] For maple (Acer spp.), powdery mildew is incited by fungi such as Sawadaea tulasnei on Norway maple (A. platanoides) or Uncinula circinata on other species, producing white powdery patches on leaves that can induce premature yellowing or reddening, mimicking early fall coloration and diminishing the tree's aesthetic quality.^[160]^[161] Severe infections in humid environments lead to leaf distortion and drop, contributing to up to noticeable reductions in nursery salability due to reduced vigor and visual appeal, though overall plant health is seldom severely compromised.^[162] These symptoms are especially problematic in dense plantings where spore dispersal is rapid. Barberry (Berberis spp.) suffers from powdery mildew caused by Microsphaera (now Erysiphe) berberidis, which forms white blotches on leaves, stunting growth, causing reddening or scorching, and promoting premature defoliation that undermines the shrub's dense, hedge-forming structure.^[163] This defoliation directly affects the plant's value as a barrier or ornamental hedge, as sparse foliage exposes the thorny branches and reduces screening effectiveness.^[164] Infections are more pronounced on young leaves in shaded, humid sites, amplifying visibility issues in garden designs. The high visibility of powdery mildew symptoms in these ornamentals heightens their impact in public and private gardens, where even minor infections can prompt removal or replacement. Spread occurs readily through international and domestic trade of infected nursery stock, introducing pathogens to new areas and complicating management.^[1] In the European Union, regulatory restrictions on certain synthetic fungicides, driven by environmental and health concerns, limit chemical control options, pushing reliance on cultural practices and emerging biological agents for suppression.^[165]

Other crops (sunflowers, Cannabis)

Powdery mildew on sunflowers (Helianthus annuus) is primarily caused by the fungus Erysiphe cichoracearum, which produces white, powdery fungal growth on leaves, stems, and heads, particularly under conditions of high humidity and moderate temperatures.^[166]^[167] Head infections are especially damaging, leading to significant reductions in seed yield and oil content, with losses estimated at 20-30% in severe cases due to impaired photosynthesis and premature senescence.^[168] The disease has become more prevalent in tropical and subtropical regions, where it can cause 30-75% disease severity on susceptible varieties.^[169] Management of powdery mildew in sunflowers relies on the use of resistant hybrids developed through breeding programs that incorporate genes from wild relatives for enhanced tolerance.^[170] For instance, germplasm lines such as R-GM-41 and R-GM-49 have shown resistance under field conditions, allowing for the creation of hybrids that maintain yield stability without heavy reliance on fungicides.^[171] Integrated approaches, including crop rotation and timely fungicide applications like propiconazole, further reduce disease incidence by up to 90% when combined with resistant varieties.^[172] In cannabis (Cannabis sativa), powdery mildew is caused by species of Golovinomyces, including G. cichoracearum and G. ambrosiae, which thrive in the dense canopies of indoor cultivation environments, leading to rapid spore dispersal and visible white patches on leaves and buds.^[173]^[174] The disease impairs plant vigor, reduces overall yield by up to 50% in untreated infestations, and lowers cannabinoid content by damaging resin glands and photosynthetic tissues.^[175]^[176] The legalization and expansion of cannabis production since the 2010s have amplified these challenges, as high-value indoor grows create ideal microclimates for pathogen proliferation.^[177] Control strategies for cannabis powdery mildew emphasize non-chemical methods suited to controlled environments, such as daily exposure to UV-C light at doses of 3-6 mJ/cm², which damages fungal DNA and suppresses development by 45% or more without residues on harvestable material.^[174]^[178] Emerging research also highlights breeding for resistance using markers like PM2, alongside environmental controls to limit humidity below 50%.^[176] Climate-driven shifts are increasing powdery mildew risks in non-traditional growing areas for both crops, as warmer temperatures and altered humidity patterns favor spore germination and spread in regions previously less affected.^[179] For sunflowers, this may expand disease pressure in subtropical zones, while indoor cannabis operations face heightened vulnerability from inconsistent climate controls.^[180]

References

[1]
Powdery Mildew / Floriculture and Ornamental Nurseries / Agriculture
Powdery mildew is the name given to diseases resulting from infection by fungi that produce a white to gray, powdery growth on the surfaces of leaves and ...Missing: definition | Show results with:definition
[2]
Mutual interplay between phytopathogenic powdery mildew fungi ...
Feb 18, 2019 · Powdery mildew is a common and widespread plant disease of considerable agronomic relevance. It is caused by obligate biotrophic fungal ...
[3]
Powdery Mildew – Vegetables - Wisconsin Horticulture
Mar 1, 2024 · Powdery mildews are diseases that occur on the above-ground parts (especially the leaves) of many agricultural crops (including vegetables), as well as ...Missing: definition | Show results with:definition
[4]
First records of powdery mildew fungi (Erysiphales) on medicinal ...
Powdery mildew fungi (Erysiphales) are obligate biotrophic plant pathogens which form conspicuous white mycelia on leaves, stems and fruits of specific ...Missing: definition | Show results with:definition
[5]
Mildew-Omics: How Global Analyses Aid the Understanding of Life ...
All powdery mildews belong to the Erysiphales, an ascomycete order that represents an ancient monophyletic lineage that evolved over 100 million years ago ( ...
[6]
(PDF) Origin and evolution of the powdery mildews (Ascomycota ...
Aug 7, 2025 · Powdery mildew is an obligate biotrophic fungus. It has no ability to develop independently and grows only by extracting nutrients from its ...
[7]
Identification of Powdery Mildew Fungi
Specialized absorption cells, termed haustoria, extend into the plant epidermal cells to obtain nutrition. While most powdery mildew fungi produce epiphytic ...
[8]
The morphology of the imperfect states of powdery mildews ...
Important characteristics are the location of the mycelium, the production of conidia singly or in chains, the presence or absence of conspicuous fibrosin ...
[9]
[PDF] A Field Guide to Insects and Diseases of California Oaks
Powdery mildew fungi overwinter as cleistothecia or, in the case of C. lanestris, as mycelium in infected buds. Cleistothecia may be less likely to form on ...
[10]
Powdery Mildew vs Downy Mildew - UF/IFAS Gardening Solutions
Downy mildew or powdery mildew—while both are called “mildew,” there are differences in how they look on your plants and how you treat the disease ...
[11]
Key Differences & Similarities In Managing Downy Mildew vs ...
Downy mildew is NOT a fungus. It belongs to a different group of fungus-like organisms called “Oomycetes” (right). Powdery mildew IS a true fungus, belonging to ...
[12]
Managing Pests in Gardens: Vegetables: Diseases: Downy mildew ...
Downy mildews are favored by cool, moist conditions while powdery mildew are favored by warm, dry conditions. Downy mildew spores are produced on branched ...
[13]
An In-Depth Evaluation of Powdery Mildew Hosts Reveals ... - PubMed
Powdery mildews are highly destructive fungal plant pathogens that have a significant economic impact on both agricultural and ecological systems worldwide.
[14]
Powdery Mildew Diseases | Pacific Northwest Pest Management ...
The economic and esthetic value of ornamental as well as fruit- and vegetable-bearing species are reduced by the unsightly appearance of powdery mildews.
[15]
The value of powdery mildew resistance in grapes: Evidence from ...
PM-resistant varieties of grapes could yield large economic benefits to California grape growers—potentially allowing cost savings as high as $48 million ...
[16]
Integrated Pest Management: History - Cornell University
From 1000 B. C. to 500 A. D., according to written records, agriculture was systematized through the formalized study of plant diseases (Theophrastus, 370 BC), ...
[17]
[PDF] Morphology and Taxonomy of Fungi - SciSpace
... classification. This has led to radical revisions which beyond doubt ... Erysiphaceae. 703. 26. Meliolaceae (Perisporiaceae). 704. 27. Remainder of ...
[18]
Grapevine powdery mildew (Uncinula necator (Schw.) Burr.)
As far as Europe is concerned the fungus was first brought to England in 1845. In 1847 Tucker and Berkeley report independently a new cryptogamic parasite on ...
[19]
Major Outbreaks in the Nineteenth Century Shaped Grape ... - Nature
Nov 26, 2019 · ... (powdery mildew), the fungus that threatened European vineyards in the 1850s. Grape phylloxera appearance almost destroyed European viticulture ...Missing: folklore | Show results with:folklore
[20]
Wine science: powdery mildew, the wine world's biggest problem
Mar 27, 2020 · Before long, it was a major problem across the vineyards of Europe. It was first spotted in French vineyards in 1847, and then in Italy in 1849.
[21]
The 3 vine pests that threatened European vineyards in the 19th ...
Feb 22, 2024 · Powdery mildew, downy mildew and phylloxera were three vine pests that devastated European vineyards in the 19th century until science helped to control them.
[22]
Phytopathology-1867-1942* - jstor
the powdery mildews. In 1863 Anton de Bary worked out the life history of a powdery mildew, Sphaerotheca castagnei, on dandelion, describing the appear-.
[23]
Fifty Years of Fungicide Development, Deployment, and Future Use
May 3, 2023 · Fungicides have and will continue to play a central role in crop protection, reducing yield loss, enhancing quality, and preserving food security worldwide.
[24]
A Short History of Fungicides - American Phytopathological Society
Mar 1, 2008 · The first case of resistance to benzimidazoles occurred in powdery mildew in greenhouses in 1969, one year after introduction. By 1984, ...
[25]
Global genomic analyses of wheat powdery mildew reveal ... - Nature
Jul 26, 2022 · Here, we study its spread and evolution by analyzing a global sample of 172 mildew genomes. Our analyses show that B.g. tritici emerged in the ...
[26]
Powdery Mildew | Home & Garden Information Center - Clemson HGIC
Sep 9, 2024 · Their common symptom is a grayish-white, powdery mat visible on the surface of leaves, stems, and flower petals. There are many hosts, and ...
[27]
Powdery Mildew / Grape / Agriculture - UC IPM
As spores are produced, the infected areas take on a white, powdery or dusty appearance. On fruit and rachises the pathogen appears as white, powdery masses ...
[28]
Powdery Mildew | Plant Problems | Illinois Extension | UIUC
Severely infected leaves gradually turn yellow, then wither, die, and finally become dry and brittle. Premature loss of the foliage results in yield losses and ...
[29]
Powdery Mildew of Grape - Ohioline
Apr 15, 2016 · Powdery mildew is caused by the fungus Uncinula necator. It was previously thought that the powdery mildew fungus overwintered inside dormant ...<|separator|>
[30]
Apple Powdery Mildew | NC State Extension Publications
Jul 3, 2018 · Net- or webbed-like russeting on the fruit surface is the most obvious symptom of fruit infection.
[31]
Powdery Mildew - Plant & Pest Diagnostics - Michigan State University
White, talcum-like colonies on the leaf surface. Chlorotic spots may be present on the leaf surface opposite the colony.
[32]
[PDF] Powdery Mildew (Erysiphe necator) of Grapevine
On leaves, powdery mildew develops best on young tissue, typically not infecting leaves more than two months old. Shoots, petioles, and clusters are also ...
[33]
Powdery Mildew of Wheat - Ohioline
Apr 12, 2016 · Greatest yield losses occur when the flag leaf becomes severely diseased by heading. Losses of up to 45 percent have been documented in Ohio on ...
[34]
Powdery Mildew on Vegetables | USU
The presence of powdery mildew reduces photosynthesis and results in reduced fruit yield and low-quality fruit due to reduced sugar levels. Infections on fruit ...
[35]
Powdery Mildew Presence in Your Garden: How to identify and ...
Jul 29, 2025 · Powdery mildews are generally easily recognized but can be mistaken for downy mildew. Downy mildew is generally only present on the ...
[36]
Use of a real-time PCR method to quantify the primary infection of ...
Jun 6, 2023 · Recently, a real-time PCR assay has been used to efficiently identify oomycetes and quantify infection levels in soil, air, and plant tissues.
[37]
Detection of Powdery Mildew Growth in Hazelnut Plant Using PCR
Therefore, this PCR-based test can identify plants that are infected with powdery mildew before they show any visual signs. From there, the infected plants can ...Missing: ELISA | Show results with:ELISA
[38]
Early Detection of Powdery Mildew Disease and Accurate ... - MDPI
Laboratory tests include enzyme-linked immunosorbent assay (ELISA), immunofluorescence, fluorescence in situ hybridization (FISH), and polymerase chain reaction ...
[39]
Use of the Scanning Electron Microscope in the Identification of ...
The taxonomy and identification of powdery mildews is based largely on characteristics of the teleomorph. However, often only the conidial stage is present ...
[40]
Of mealy bugs and powdery mildew - Succulents and More™
Jul 20, 2012 · Powdery mildew, on the other hand, is a fungal disease. Most experts recommend discarding the infected plant, but I'm not ready to let go of my ...
[41]
Enhancing identification accuracy for powdery mildews using ...
Others fail due to amplification and sequencing difficulties and lack of informative variability. Powdery mildews (Ascomycota, Erysiphales) are biotrophic, ...
[42]
Discover hidden taxa of Erysiphe section Erysiphe fungi ... - MycoKeys
Jun 4, 2025 · Mycelium on leaves and stems, effuse or in irregular powdery layers, white, persistent; hyphae 3–8 μm wide; hyphal appressoria nipple-shaped to ...
[43]
Long‐term and rapid evolution in powdery mildew fungi
Mar 2, 2023 · The disease is characterized by a white, powdery tarnish on the plant surfaces, formed by the fungal epiphytic mycelium and conidia. Powdery ...Abstract · LONG-TERM EVOLUTION OF... · DRIVERS OF RAPID...
[44]
https://doi.org/10.1007/s10267-003-0159-3
[45]
https://www.tandfonline.com/doi/full/10.1080/00275514.2025.2554558
[46]
Australia: A Continent Without Native Powdery Mildews? The First ...
Powdery mildews (Ascomycota, Erysiphales) are common obligate biotrophic fungal plant pathogens, comprising ~900 species that infect more than 10,000 dicot and ...
[47]
Status, Gaps and Perspectives of Powdery Mildew Resistance ...
Mar 6, 2024 · Seven PM species with different taxonomic positions, host ranges, geographic distributions and ecological requirements are known on cucurbits.
[48]
Beyond Nuclear Ribosomal DNA Sequences - NIH
Altogether, powdery mildew fungi can colonize more than 10,000 dicot and monocot species in different parts of the world (Amano, 1986; Braun and Cook, 2012).
[49]
Geographic distribution, species spectrum and variation of powdery ...
Sep 3, 2025 · This polyphagous species with a wide host range (e.g., hosts pertaining to the families Asteraceae, Solanaceae, Fabaceae, or Cucurbitaceae) ...
[50]
Comparative genome analyses reveal sequence features reflecting ...
Sep 25, 2018 · Notably, while monocot (grass) PM fungi exhibit high-level of host-specialization, many dicot PM fungi display a broad host range. To understand ...
[51]
Mosaic genome structure of the barley powdery mildew pathogen ...
Because haploid powdery mildews harbor either of these two mating-type loci to control mating compatibility for sexual reproduction (33), this validates at ...Missing: post- | Show results with:post-
[52]
Genetic characterization of the Golovinomyces cichoracearum ...
Jan 7, 2010 · ... host range to the Asteraceae (Braun, 1987). It is closely related to Golovinomyces orontii (=Erysiphe orontii), which is a polyphagous ...
[53]
Non-parent of Origin Expression of Numerous Effector Genes ...
Jan 29, 2018 · Powdery mildew is an important disease of cereals. It is caused by one species, Blumeria graminis, which is divided into formae speciales ...Missing: intraspecies mating
[54]
Combating powdery mildew: Advances in molecular interactions ...
This review gives a succinct overview of the molecular basis of interactions between wheat and Bgt, and wheat defense mechanisms against Bgt infection.
[55]
Conidial Germination, Infection Structure Formation, and Early ...
At 20°C (85% relative humidity), conidia germinated and formed an appressorium within 6 h of inoculation. Germination over time followed a monomolecular curve ( ...Missing: latency | Show results with:latency
[56]
A framework for examining inter-regional aerial transport of fungal ...
Aerial transport of fungal spores has no doubt been responsible for occasionally spreading plant diseases over distances of 500 km or more.
[57]
Global genomic analyses of wheat powdery mildew reveal ...
Jul 26, 2022 · ... distances (~>500 km) effectively discriminate mildew populations. The Fertile Crescent is the likely region of origin of wheat powdery mildew.<|control11|><|separator|>
[58]
The rose powdery mildew (Podosphaera pannosa) - SciELO México
... powdery mildew stands between them. This disease is caused by the ... In most cases conidiophores generate one conidia per day, but under optimal ...
[59]
Exercise: Powdery Mildew Fungi: Classification and Ecology
Powdery mildew fungi are ideal for use in a laboratory exercise on fungal classification, fungal spore types, host-parasite interaction during an ecology unit, ...
[60]
Grapevine - Biology, epidemiology - Ephytia
Sexual reproduction occurs when two compatible mycelia meet (of opposite sexual signs called "MAT 1" and "MAT 2" for MAting Types 1 and 2). After fusion and ...
[61]
Powdery Mildew - an overview | ScienceDirect Topics
Powdery mildew is a fungal disease, caused by fungi, that appears as a powdery tarnish on plant surfaces, and is a common plant disease.
[62]
Dispersal of cereal mildews across Europe - ScienceDirect
With the number of generations of the polycyclic disease, the number of spores produced per cycle, the height of spore release in the canopy, and their terminal ...
[63]
[PDF] Powdery mildew factsheet version 2.pub
The matted mycelium pushed myriads of thumblike haustoria down into the epidermal cells, until the leaves withered and died.” Pathogens. Several genera cause ...Missing: time | Show results with:time
[64]
The role of sexual stage in the over-summering of Erysiphe graminis ...
The sexual stage of E. graminis f.sp. hordei was found to be functional in Israel, and adapted to the climate of the region. Cleistothecia serve as the ...
[65]
Functional Characterization of Pseudoidium neolycopersici ...
May 28, 2020 · Different DNA damage repair mechanisms include nucleotide excision repair, recombination repair, mutagenic repair, and photolyase-mediated ...
[66]
The contribution of DNA repair pathways to genome editing and ...
This review summarizes and compares the molecular mechanism, hierarchy, and regulation of four DNA double-strand break repair pathways in animal and fungal ...
[67]
Wavelength dependent recovery of UV-mediated damage
Because of its obligate biotrophic nature, it was difficult to prove the existence of a self-repair mechanism in powdery mildew fungi. O. neolycopersici, the ...
[68]
Examination of Gene Loss in the DNA Mismatch Repair Pathway ...
The genomes of these powdery mildews show elevated rates of diverse types of mutation, raising the hypothesis that these organisms have diversified while ...
[69]
Examination of Gene Loss in the DNA Mismatch Repair Pathway ...
Abstract. The DNA mismatch repair (MMR) pathway corrects mismatched bases produced during DNA replication and is highly conserved across the tree of life,
[70]
Fungicide Resistance in Powdery Mildew Fungi - PubMed Central
In general, powdery mildew fungi show both asexual and sexual life cycles (Figure 2). The asexual life cycle begins after a conidium lands on a susceptible host ...
[71]
Powdery Mildew
### Environmental Conditions Promoting Powdery Mildew
[72]
Cucurbit powdery mildew | Vegetable Pathology - Cornell blogs
Dry conditions favor colonization, sporulation, and dispersal. Optimum temperature for disease development is 68-81°F; infection can occur between 50 and 90°F.
[73]
[PDF] i RECIPROCITY OF IRRADIANCE AND DURATION OF THE ...
More time is required at higher or lower temperatures, and virtually no germination occurs below 6C or above 35C (Delp. Page 10. 2 et al., 1954). The pathogen ...
[74]
Powdery Mildew on Ornamentals - UC IPM
Moderate temperatures of 60° to 80°F and shady conditions generally are the most favorable for powdery mildew development. Powdery mildew spores and mycelium ...Missing: optimal | Show results with:optimal
[75]
[PDF] Powdery Mildew - Clemson Blogs
Therefore, shaded areas, dense canopies, close plant spacing, and poor air circulation are highly favorable for powdery mildew development. Cultural ...
[76]
Powdery Mildews | Colorado State University Extension Website
Oct 1, 1999 · Powdery mildews are severe in warm, dry climates. Prefer high humidity at night and low humidity during the day. Prefer warm temperatures ...Missing: splotchy | Show results with:splotchy
[77]
Effects of Climate Change on Epidemics of Powdery Mildew in ...
Jul 26, 2017 · The results of the present study demonstrate that changes in climate contributed to the increase in wheat powdery mildew.
[78]
Unraveling the Intricacies of Powdery Mildew: Insights into ... - MDPI
Young plant tissues undergoing active development, such as young leaves and buds, are particularly susceptible to powdery mildew infection. Their persistent ...
[79]
Cellulose/callose glucan networks: the key to powdery mildew ...
Sep 19, 2016 · However, the effectiveness of callose deposition in pathogen-induced papillae was challenged by the observation that callose-rich papillae were ...
[80]
Elevated Early Callose Deposition Results in Complete Penetration ...
We show that callose can strongly support penetration resistance when deposited in elevated amounts at early time points of infection.
[81]
Full article: Powdery mildews on crops and ornamentals in Canada
All species in Sphaerotheca and Microsphaera, Uncinula, etc., were made into new combinations, i.e. Podosphaera spp. and Erysiphe spp., respectively.
[82]
Sulfur as Part of a Powdery Mildew Control Program
Sep 20, 2021 · In a UC Ag Expert webinar, Bettiga said sulfur was first used in 1850 to control powdery mildew. More sulfur is used in vineyards than any other ...Missing: folklore | Show results with:folklore
[83]
A long term field study of the effect of fungicides penconazole and ...
Oct 17, 2014 · Treatment with sulfur (blocks SA and SB) was as effective as treatment with penconazole (blocks PA and PB) which provided up to 85% average ...
[84]
Current Status of the Powdery Mildew Fungicide Toolbox in Cherries
Apr 28, 2020 · The compounds become ineffective when the target gene of the pathogen, erg11/ cyp51 is mutated at various key nucleotide positions. Additionally ...<|control11|><|separator|>
[85]
Efficacy of difenoconazole, tebuconazole, and difenoconazole-TTO ...
Difenoconazole-TTO, at both rates, was significantly more effective than tebuconazole at controlling powdery mildew, providing 98-99% efficacy.
[86]
[PDF] Powdery Mildew Efficacy
fungicide treatments significantly reduced powdery mildew development (Table 50). ... In an azalean experiment, Garden Fungicide (sulfur) had several necrotic or ...
[87]
Widespread QoI resistance and emergence of DMI resistance in ...
Apr 8, 2020 · It is therefore now recommended that one add sulfur with either DMI or QoI fungicides if one is unclear as to whether resistance has developed; ...
[88]
Powdery Mildew on Vegetables - UC IPM
Fertilize properly because too much nitrogen causes lush foliage and shade, providing conditions for fungal growth. Plant resistant varieties. Some plants ...Quick Tips · Pest Notes: Introduction · Identification and Damage · Life Cycle
[89]
Cross-resistance to the new fungicide mefentrifluconazole in DMI ...
In the European Union (EU), regulation of sterol demethylation inhibiting (DMI) fungicides is tightened due to their suspected endocrine disrupting ...
[90]
Common Fungicide Damages Muscles that Bees Use to Fly
Feb 28, 2017 · Myclobutanil, a systemic fungicide commonly used in agriculture and home gardens, can cause significant damage to the muscles that honey bees use to fly and ...
[91]
Fungi Parasitizing Powdery Mildew Fungi: Ampelomyces Strains as ...
Ampelomyces strains are studied in detail, particularly regarding their use as biocontrol agents (BCAs) of powdery mildew (PM) fungi.
[92]
(PDF) Biology and biocontrol potential of Ampelomyces ...
Aug 9, 2025 · This review summarizes the taxonomy, genetic diversity, life cycle, mode of action, natural occurrence, host range, biocontrol potential, mass production and ...
[93]
Ampelomyces quisqualis AQ10, CNCM I-807, for biological control ...
This novel strain is termed AQ10 and has CNCM Accession Number I-807, and was found to be a hyperparasite of the causative fungi of powdery mildew.
[94]
Ampelomyces mycoparasites of powdery mildews – a review
In 1870, Anton de Bary described the Ampelomyces-plant pathogenic mycohost interaction in detail, which involves the hyperparasite's hyphae and pycnidia. de ...
[95]
An iolinid predatory mite feeds on powdery mildew | BioControl
Jul 31, 2025 · Our findings indicate that consumption of the fungus is one of the mechanisms by which this iolinid mite suppresses powdery mildew infections in ...
[96]
Biology and Co-Occurrence of Psyllobora vigintimaculata taedata ...
May 1, 2009 · Biological control of powdery mildew (PM) plant pathogens may offer a solution to chemical control problems such as resistance, worker ...
[97]
The antagonistic strain Bacillus subtilis UMAF6639 also confers ...
Our results demonstrated that UMAF6639 confers protection against cucurbit powdery mildew by activation of jasmonate- and salicylic acid-dependent defence ...
[98]
(PDF) Bacillus subtilis for the control of powdery mildew on ...
Bacillus subtilis as a biological control agent is extremely attractive for making a bioproduct for large-scale commercial use, considering that this ...<|control11|><|separator|>
[99]
Efficacy of the biocontrol agents Bacillus subtilis and Ampelomyces ...
Mar 31, 2016 · Efficacy of the biocontrol agents Bacillus subtilis and Ampelomyces quisqualis applied in combination with fungicides against powdery mildew of ...
[100]
Ampelomyces quisqualis: The Mycoparasitic Fungus for Sustainable ...
Aug 11, 2025 · The biocontrol mechanism of A. quisqualis is direct and destructive: it infects the powdery mildew fungus itself, thereby protecting the plant ...<|control11|><|separator|>
[101]
Evaluating the efficacy of microbial antagonists in inducing ...
B. amyloliquefaciens strain YN201732, a beneficial endophyte isolated from tobacco, was found effective in controlling tobacco powdery mildew and inducing ...
[102]
Bacterial and Fungal Biocontrol Agents for Plant Disease Protection
This review aims to highlight the importance of biocontrol strategies for managing crop diseases. Furthermore, the role of beneficial microbes in controlling ...
[103]
Genetic dissection of the powdery mildew resistance in wheat ...
There are two types of resistance patterns to powdery mildew: qualitative resistance and quantitative resistance [10], [11], [12], [13]. Qualitative ...
[104]
Mechanisms of powdery mildew resistance of wheat – a review of ...
Feb 20, 2020 · Modern genomic technology has been combined with traditional breeding techniques to improve wheat powdery mildew resistance.<|control11|><|separator|>
[105]
The barley immune receptor Mla recognizes multiple pathogens and ...
Nov 25, 2021 · Within the locus, resistance to barley powdery mildew (B. graminis f. sp. hordei; Bgh) is conferred by members of the RGH1 gene family. Mla has ...
[106]
The powdery mildew resistance gene REN1 co-segregates with an ...
Dec 30, 2009 · The REN1 locus has multiple layers of structural complexity compared with its two closely related paralogous NBS clusters, which are located ...
[107]
Rapid generation of a transgene-free powdery mildew resistant ...
Mar 28, 2017 · In this study, we report on generating, in less than ten months, Tomelo, a non-transgenic tomato variety resistant to the powdery mildew fungal pathogen using ...
[108]
Development of Powdery Mildew Resistance in Cucumber Using ...
Jun 20, 2023 · These results provide the basis for generating transgene-free powdery mildew resistance in cucumber in any genetic background.Missing: NHEJ | Show results with:NHEJ
[109]
ADDITIONAL SOURCES OF REN1-LIKE POWDERY MILDEW ...
The discovery of the powdery mildew resistance locus, Ren1, in two Central Asian Vitis vinifera cultivars, 'Kishmish vatkana' and 'Dzhandzhal kara', ...
[110]
War and Peas: Molecular Bases of Resistance to Powdery Mildew in ...
Under suitable conditions, powdery mildew is able to cause up to a 50% loss in the yield of legumes such peas or soybeans [13].
[111]
Scientists uncover DNA sequence of key wheat disease resistance ...
Feb 28, 2009 · To address such breakdowns in resistance, CIMMYT adopted a breeding strategy that entailed searching among diverse sources for resistance genes ...
[112]
Blumeria graminis (powdery mildew of grasses and cereals)
Among the pathogens of wheat in Argentina, powdery mildew practically occurs every year in the wheat cropping area, particularly in the first growth stages and ...
[113]
Management of powdery mildew in cereals - AHDB
Varietal resistance, cultural control and fungicides all help ensure that this foliar pathogen rarely causes major issues in the UK.Missing: epidemics | Show results with:epidemics<|separator|>
[114]
Powdery Mildew of Wheat - Crop Protection Network
Mar 19, 2019 · The characteristic sign of the powdery mildew pathogen is fluffy, white to gray fungal growth on the top surface of leaves. Yellowish spots ...
[115]
[PDF] Wheat Diseases Identification Pocket Guide - SDSU Extension
Symptoms and source of inoculum: Powdery mildew starts as raised, white, powdery spots on the lower leaves . The powdery mildew pathogen survives the winter in ...
[116]
Surveys of cereal diseases and pests in the Netherlands. 4 ...
An average of 29 and 70% of fields were infected by powdery mildew in May and July, respectively. Mildew prevalence in May was positively correlated with ...Missing: outbreaks | Show results with:outbreaks
[117]
Important wheat diseases in the US and their management in the ...
$$1 billion loss is incurred annually worldwide (Figueroa et al., 2018). ... world. Wheat infected with powdery mildew suffers from both qualitative (grain ...
[118]
Dominant resistance to barley powdery mildew race D1, isolated ...
After treatments with ionizing radiations and chemicals in the commercial barley varieties 'Bonus', 'Mari', 'Pallas', and 'Kristina', 43 lines with dominant ...
[119]
Toxicity of Strobilurins fungicides: A comprehensive review
Oct 9, 2023 · It is widely used against powdery mildew, white mold, rot, downy mildew, rust, and rice blast diseases in different crops like soybeans ...
[120]
Understanding Powdery Mildew: Impact and Management
For instance, powdery mildew in grapevines can cause up to 30% yield loss if left uncontrolled. The disease affects not only the quantity but also the quality ...Damage Symptoms · Economic And Agricultural... · This Manipulation Of Host...<|control11|><|separator|>
[121]
Banish bunch rots in grapes - MSU Extension
Aug 21, 2012 · Entry holes created by grape berry moth larvae are a common cause of bunch rot as well. In addition, infection by the powdery mildew fungus ...Missing: facilitation | Show results with:facilitation
[122]
Effect of powdery mildew on wine quality - Wiley Online Library
In addition, samples from powdery mildew-affected grapes were more pronounced in fungal, earthy and cooked tomato aroma attributes (wine) and dusty and mushroom ...
[123]
RESEARCH NOTE POWDERY MILDEW SENSORY EFFECT ON ...
The wines made from the mildewed grapes were clearly of a lower quality. Comments ranged from more bitter to distinct off tastes for the mildewed samples.Missing: flavors | Show results with:flavors
[124]
Grapevine Powdery Mildew: Fungicides for Its Management and ...
Jul 20, 2021 · Grapevine powdery mildew is a major disease of cultivated and wild grapevine species worldwide causing substantial yield and economic losses [1] ...
[125]
The grape powdery mildew resistance loci Ren2, Ren3, Ren4D ...
Only one NLR gene associated with PM resistance, MrRUN1, has been characterized in M. rotundifolia G52 (Feechan et al., 2013) and candidate NLR genes associated ...
[126]
Powdery Mildew Resistance Genes in Vines - PubMed Central - NIH
Jun 18, 2022 · In some of these loci, the study of the infection process ... powdery mildew resistance gene Pm21, confes powdery mildew resistance in wheat.
[127]
[PDF] Managing powdery mildew - The Australian Wine Research Institute
Using canopy management techniques to encourage air movement, the penetration of sunlight and spray penetration into the canopy;. • Careful use of water and ...
[128]
Management of Powdery Mildew in Beans - University of Florida
Powdery mildew, caused by the fungal organism Erysiphe polygoni, is one of the most commonly occurring diseases on many types of beans.Symptoms · Infection And Spread · Management Practices
[129]
Bean & Southern Pea Diseases | Home & Garden Information Center
Jun 6, 2025 · Powdery Mildew. Leaves are covered with patches of a whitish to grayish powdery growth. This disease is caused by the fungus Erysiphe polygoni.Anthracnose · Bean Root Rots · Bacterial Blights
[130]
Powdery mildew of chickpea - Publication : USDA ARS
Technical Abstract: Powdery mildew of chickpea is caused by several fungi including Leveillula taurica, Erysiphe pisi and possible other Erysiphe spp. The most ...Missing: polygoni beans
[131]
Pea Diseases - Agriculture - Vikaspedia
The leaves turn yellow and die. The fruits do not either set or remain very small. It causes defoliation. Later stages, powdery growth also covers the pods.
[132]
[PDF] Yield Response and Resistance of Dry Beans to Powdery Mildew in ...
We took advantage of the opportunity to evaluate the disease reactions and subsequent yield losses attributable to powdery mildew. MATERIALS AND METHODS. The ...
[133]
Soybean Seed Yield Losses Caused by Powdery Mildew I - ACSESS
The mean loss of yield caused by powdery mildew in these three cul- tivars was 10.1%.Missing: US | Show results with:US
[134]
Powdery mildew on soybean | UMN Extension
The disease rarely appears to rarely cause yield loss, but it can potentially cause defoliation and reduced yields in susceptible varieties.
[135]
[PDF] Evaluation of the reaction of several alfalfa cultivars to powdery mildew
Diseased alfalfa produces a lower yield and has a reduced harvesting period. ... Relative measurements can also be estimated by measuring the amount of tissue ...
[136]
[PDF] Field Diagnosis of Chickpea Diseases and their Control
Powdery mildew [Leveillula taurica (Lev. ) Salmon] ............19 ... If the plants survive up to the podding stage, pod set is sparse. Many plants dry.
[137]
Genetic mapping of the powdery mildew resistance gene in soybean ...
Powdery mildew (PMD) of soybean [Glycine max (L.) Merr.] is caused by the fungus Microsphaera diffusa. Severe infection of PMD on susceptible varieties ...Missing: 229358 | Show results with:229358
[138]
Powdery Mildew Epidemics in Grain Legumes and Their ...
Sep 14, 2025 · We review the status of powdery mildew on grain legumes, detection and identification of the pathogens (Erysiphe, Podosphaera and Leveillula ...
[139]
Powdery Mildew on Onions - Utah State University Extension
Leveillula taurica is a powdery mildew fungus capable of infecting onions, garlic, and over 1000 plants in various genera and species (Braun, 1987 and 1995).
[140]
Onion - Texas Plant Disease Handbook
Powdery mildew (fungus – Leveillula taurica): Powdery mildew occurs rarely in the Lower Rio Grande Valley of Texas. The earliest symptom is a pale discoloration ...
[141]
Powdery mildew of cucurbits | UMN Extension
Powdery mildew infections favor humid conditions with temperatures around 68-81° F. In warm, dry conditions, new spores form and easily spread the disease.Quick Facts · How To Tell Powdery Mildew... · BiologyMissing: splotchy | Show results with:splotchy
[142]
Cucurbit Powdery Mildew | Cornell Vegetables
The conidia (spores produced asexually) of E. cichoracearum and P. xanthii are difficult to distinguish and chasmothecia, which are sexual fruiting bodies ( ...
[143]
Powdery Mildew / Strawberry / Agriculture - UC IPM
Powdery mildew causes white powdery colonies on leaf undersides, rolling edges, and reddish blotches. It's introduced by planting material and spores, and is ...
[144]
Strawberry Powdery Mildew Caused by Podosphaera aphanis
Strawberry powdery mildew, caused by Podosphaera aphanis, affects leaves, fruit, and runners of strawberry plants. Infected leaves have reduced ...
[145]
Powdery Mildew on Fruits and Berries - UC IPM
Identification and Damage. Powdery mildew can be recognized easily on most plants by the white to gray powdery mycelium and spore growth that forms on both ...
[146]
[PDF] Powdery Mildew of Strawberry - CT.gov
Powdery mildew is a fungal disease causing white mildew on leaves, upward curling, reddish-brown spots, and deformed or no fruit. It spreads via spores and ...
[147]
Apple Powdery Mildew (Podosphaera leucotricha) - Cornell CALS
Apple powdery mildew is a disease caused by the fungus *Podosphaera leucotricha* that can decrease shoot growth, affect vigor, and cause russeting on fruit.
[148]
Apple Disease - Powdery Mildew - Penn State Extension
Jan 5, 2024 · Powdery mildew, caused by the fungus Podosphaera leucotricha, attacks buds, blossoms, leaves, new shoots, and fruit of wild and cultivated apples and ...
[149]
Powdery mildew of apple and pear - Integrated Pest Management
Powdery mildew appears as white, felt-like patches on leaves, causing stunted fruit. It affects apples and pears, and is managed with fungicides and resistant ...
[150]
Apple Powdery Mildew - WSU Tree Fruit - Washington State University
Research has shown that pruning can significantly decrease apple powdery mildew incidence on both shoots and fruit, especially when combined with fungicide ...
[151]
Disease-Resistant Apple Cultivars - MU Extension
Apr 5, 2022 · Liberty An older cultivar, released in 1978, that has broad resistance to apple scab, fire blight, cedar apple rust and powdery mildew and, ...
[152]
Apple Cultivars: Scab Resistance Selections - Penn State Extension
May 30, 2023 · Field observations indicate the tree has good resistance to fire blight and moderate resistance to powdery mildew. It is susceptible to cedar ...
[153]
[PDF] Apple – Powdery Mildew (Podosphaera leucotricha) - UMass Amherst
Use fungicides that also control apple scab, making sprays at weekly intervals from tight cluster to terminal bud set. Symptoms. Powdery mildew (PM) ...
[154]
Powdery Mildew : Landscape - UMass Amherst
Dec 30, 2019 · Infections result in a range of symptoms that can include: reduced growth, lower fruit production or fruit blight, foliar scorch or blotch, ...
[155]
Maple: Powdery mildew | Hortsense | Washington State University
Jul 7, 2025 · Powdery mildew of maple is a fungal disease which affects many hardwoods including maple, hazel, birch, and alder.
[156]
Lilac Syringa - CT.gov
White mealy appearance of leaves in late summer indicates powdery mildew infection. It is unsightly but does no harm to the bush. This common disease of lilac ...
[157]
Lilac Pests - University of Vermont
Aug 9, 2024 · All powdery mildews are favored by the same conditions: high humidity, cool nights and warm days, so it tends to show up on several different ...
[158]
Powdery mildews on lilac in western North America ... - PubMed
May 17, 2017 · Two powdery mildews, Erysiphe syringae and the previously undescribed Phyllactinia syringae, sp. nov., occur on lilac in western North America.Missing: mildew | Show results with:mildew
[159]
Common Disease Pests of Maple in North Carolina
May 13, 2022 · Powdery Mildew The fungi thrive and spread most readily in humid conditions. Severe infestations may cause premature leaf drop, but powdery ...
[160]
Maple | Texas Plant Disease Handbook
Powdery Mildew (fungus – Uncinula circinata): White fungus growth on leaves. Rarely serious enough to use control measures. Cotton Root Rot (fungus – ...
[161]
Sawadaea tulasnei Powdery Mildew of Norway Maple (Acer ...
Norway maple leaves bearing powdery mildew were collected from one location in the fall of 2003 and four locations (as much as 1.5 km apart) in the fall of ...
[162]
Barberry > Leaves > Spot or blotches on leaves
White spots or blotches on leaves · In severe cases leaves may be completely coated with white powdery fungal growth · Leaves may be stunted, reddened, scorched ...
[163]
Barberry | Home & Garden Information Center - Clemson HGIC
Sep 15, 1999 · Powdery mildew, a fungal disease that causes a white coating on the leaves;; Phyllosticta leaf spot, which causes purple spots on the leaves ...
[164]
[PDF] The future of crop protection in Europe - European Parliament
Herbicides, insecticides and fungicides protect crops against harmful weeds, insects and diseases. However, the use of PPPs is subject to societal concerns ...
[165]
Sunflower (Helianthus spp.)-Powdery Mildew
The fungus, reported to overwinter as chasmothecia on plant residue, is favored by conditions that produce high humidity but dry leaves. It is a highly ...
[166]
[PDF] Diseases of Sunflower in California
Powdery mildew (caused by Erysiphe cichoracearum DC.) was the second most prevalent disease in 1989 and was consistently observed every year between. 1983 and ...Missing: impact | Show results with:impact
[167]
Powdery mildew disease in sunflower : A review
Dec 31, 2015 · Currently, the disease is observed on the crop in all growing situations viz., kharif, rabi and spring recording 30-75 per cent disease severity ...
[168]
An Insight into Powdery Mildew–Infected, Susceptible, Resistant ...
Jun 19, 2018 · Powdery mildew (PM) incited by Golovinomyces orontii has become a serious problem on sunflower in the tropics and subtropics recording 30–75% ...
[169]
[PDF] Transferring Powdery Mildew Resistance Genes from Wild ...
Sunflower cultivars differ in their reaction to PM, but resistant cultivars are not available and relatively little effort has been devoted to develop resistant.Missing: hybrids | Show results with:hybrids
[170]
[PDF] Identification of sunflower powdery mildew resistant sources under ...
The identification of 2 sunflower germplasm lines (R-GM-41 & R-GM-49) as resistant to powdery mildew can serve for the immediate sunflower breeding programmes ...
[171]
Management of sunflower powdery mildew through varieties and ...
Jul 3, 2025 · Disease management methods such as use of pathogen-free seeds, residue removal, crop rotation and cleaning seed containers before storage are ...Missing: Clearfield | Show results with:Clearfield
[172]
Characterization of Powdery Mildew Fungi Affecting Hemp in the ...
Jan 24, 2024 · Hemp is susceptible to infection by multiple species of powdery mildew fungi, with Golovinomyces ambrosiae being the most common. Since 2018, ...
[173]
Evaluation of disease management approaches for powdery mildew ...
Dec 3, 2020 · Scanning electron microscopic images showing growth of the powdery mildew pathogen on leaf surfaces of untreated cannabis plants were compared ...
[174]
The Grower's Battle Against Powdery Mildew: Best Practices for ...
Dec 17, 2024 · In severe infestations, yields can plummet by as much as 50%, while cannabinoid and terpene content take a nosedive.Prevention Is Key · Breeding For Powdery Mildew... · Treatment Options<|separator|>
[175]
PM2: The Key to Powdery Mildew Resistance? - JumpLights®
Apr 15, 2025 · Powdery mildew can be a devastating disease for any type of growing environment, reducing yield and cannabinoid content. As new breeding ...
[176]
Pathogens and Molds Affecting Production and Quality of Cannabis ...
Plant pathogens infecting marijuana (Cannabis sativa L.) plants reduce growth of the crop by affecting the roots, crown, and foliage.
[177]
Shedding the Light on Powdery Mildew - Annual Reviews
Sep 9, 2024 · ... review ... Determination of UV action spectra affecting the infection process of Oidium neolycopersici, the cause of tomato powdery mildew.
[178]
New challenges for sunflower ideotyping in changing environments ...
Apr 14, 2021 · However, high sunflower density can also lead to disease attacks such as white mold and phomopsis stem canker (Debaeke et al., 2014), as well ...
[179]
The Impact Of Climate Change On Sunflower Crops | Nuseed Europe
Jan 29, 2019 · It's likely that regions where rainfall decreases, and temperature rise will see a fall in diseases that require free water to facilitate their ...Missing: cannabis | Show results with:cannabis