Management Of Powdery Mildew Research Articles

What Explains Hop Growers' Fungicide Use Intensity and Management Costs in Response to Powdery Mildew?

Methods for causal inference from observational data are common in human disease epidemiology and social sciences but are used relatively little in plant pathology. We draw upon an extensive data set of the incidence of hop plants with powdery mildew (caused by Podosphaera macularis) collected from yards in Oregon from 2014 to 2017 and associated metadata on grower cultural practices, cultivar susceptibility to powdery mildew, and pesticide application records to understand variation in and causes of growers' fungicide use and associated costs. An instrumental causal forest model identified growers' spring pruning thoroughness, cultivar susceptibility to two of the dominant pathogenic races of P. macularis, network centrality of yards during May-June and June-July time transitions, and the initial strain of the fungus detected as important variables determining the number of pesticide active constituents applied by growers and the associated costs they incurred in response to powdery mildew. Exposure-response function models fit after covariate weighting indicated that both the number of pesticide active constituents applied and their associated costs scaled linearly with the seasonal mean incidence of plants with powdery mildew. Although the causes of pesticide use intensity are multifaceted, biological and production factors collectively influence the incidence of powdery mildew, which has a direct exposure-response relationship with the number of pesticide active constituents that growers apply and their costs. Our analyses point to several potential strategies for reducing pesticide use and costs for management of powdery mildew on hop. We also highlight the utility of these methods for causal inference in observational studies.

Eco-friendly Management of Powdery Mildew of Pea (Pisum sativum L.)

Pea (Pisum sativum L) is an important crop grown all over the world, in India commonly known as "Matar". India is ranked second in both area and production of pea globally. Erysiphe polygoni DC causes powdery mildew in pea, it is a one of most devastating disease. An experiment was conducted at the SKNCOA farm in Jobner during the Rabi season of 2021. Six natural products, including Panchgavya (10%), Butter milk (10%), Neem seed kernel extract (NSKE 10%), Duranta (10%), Parthenium (10%), and Mehandi (10%), were used as two foliar sprays. During the assessment, all treatments were shown to be effective against powdery mildew of pea, although Neem Seed Kernel Extract (NSKE 10%) and Panchgavya (10%) were determined to be the best treatments for controlling powdery mildew disease in pea.

Glycine tabacina, native to Australia, is an alternate host of Erysiphe diffusa causing powdery mildew on soybean

AbstractPowdery mildew, caused by Erysiphe diffusa, is an emerging pathogen in Australian soybean crops. Since its initial detection in 2012, the disease has been observed every season in soybean paddocks throughout Australia. It is not known how E. diffusa survives between soybean cropping seasons in the Australian environment. This study identified the native Glycine species, G. tabacina, as an alternate host for E. diffusa in Australia. G. tabacina specimens naturally infected with powdery mildew were collected and the pathogen was identified based on morphological characters and nrDNA ITS and MCM7 sequences. Cross‐inoculation experiments demonstrated that the E. diffusa isolates infecting G. tabacina in the field were pathogenic to soybean. This study is the first to report E. diffusa on G. tabacina in Australia. As a perennial native often found in the vicinity of the annual soybean crops, G. tabacina can easily serve as an alternate host for E. diffusa and could be an example of a host range expansion in this powdery mildew species. Weed control in soybean crops, with special attention to the removal of the native Glycine species, may be an option for powdery mildew management for Australian soybean growers.

Chemical and nutritional management of powdery mildew caused by Sphaerotheca fuliginea on pumpkin vines

Pumpkin is a popular vegetable crop in Pakistan and India which is grown in rainy season. Numerous biotic and abiotic factors have an impact on this crop. Sphaerotheaca fuliginea is one of the biotic agents that poses a major risk to the crop, leading to significant losses in both quantity and quality. Applying nutritional supplements to strengthen resistance against pumpkin powdery mildew infection is an economical and ecologically sustainable approach to managing the disease. Three treatments including 1% potassium monophosphate, 1% potassium silicate, and their combination (1:1) given in the field have been tested in order to control the disease. The spraying procedure used before the inoculation revealed that the disease was infected. A maximum 49% decrease in disease was achieved in the control group when potassium silicate and mono potassium phosphate were combined. The distinctive effects of 1% potassium silicate and 1% potassium phosphate mono shown, for comparison control, a 43% and 39% lower incidence of disease, respectively. In the field, tests were conducted to determine the efficacy of three fungicide combinations: Bravo (chlorothainal), score (Difenaconzole), and Bravo + score. The standard concentration of each combination was tested against S. fuliginea. The disease control was reduced by 61% when the two fungicides were combined (Bravo+ score). Compared to the control, the partition effect score and Bravo produced a 56% and 54% reduction in disease, respectively. By choosing an appropriate formulation and application technique of nutritional supplements can be effectively used in inhibiting the growth of S. fuliginea.

Bioefficacy Studies of <i>Trichoderma asperelloides</i> and <i>Ampelomyces quisqualis</i> in Combination with Sulphur for the Management of Powdery Mildew of Grapes

A field experiment was carried out to evaluate the bio-efficacy of Trichoderma asperelloides and Ampelomyces quisqualis against powdery mildew of grapes at ICAR- National Research Centre for Grapes, Pune in 2021-22 and 2022-23. It was observed, that spray and drench of Trichoderma asperelloides @ 2 mlL-1 along with drench of Ampelomyces quisqualis @ 5 mlL-1 and spray of Sulphur @ 2gL-1 of water manifested the lowest percent disease index on leaves and bunches with PDI 21.84 and 19.21 respectively. The percent disease control on leaves and bunches was 54.64 and 59.04 respectively. Moreover, the application of Trichoderma asperelloides and Ampelomyces quisqualis solo and in combination with sulfur showed a significant impact on qualitative parameters such as pH, total soluble solids, acidity, berry diameter, berry length and shelf life. Hence this treatment may be recommended for the management of powdery mildew of grapes.

Deciphering the Genomic Landscape and Virulence Mechanisms of the Wheat Powdery Mildew Pathogen Blumeria graminis f. sp. tritici Wtn1: Insights from Integrated Genome Assembly and Conidial Transcriptomics.

A high-quality genome sequence from an Indian isolate of Blumeria graminis f. sp. tritici Wtn1, a persistent threat in wheat farming, was obtained using a hybrid method. The assembly of over 9.24 million DNA-sequence reads resulted in 93 contigs, totaling a 140.61 Mb genome size, potentially encoding 8480 genes. Notably, more than 73.80% of the genome, spanning approximately 102.14 Mb, comprises retro-elements, LTR elements, and P elements, influencing evolution and adaptation significantly. The phylogenomic analysis placed B. graminis f. sp. tritici Wtn1 in a distinct monocot-infecting clade. A total of 583 tRNA anticodon sequences were identified from the whole genome of the native virulent strain B. graminis f. sp. tritici, which comprises distinct genome features with high counts of tRNA anticodons for leucine (70), cysteine (61), alanine (58), and arginine (45), with only two stop codons (Opal and Ochre) present and the absence of the Amber stop codon. Comparative InterProScan analysis unveiled "shared and unique" proteins in B. graminis f. sp. tritici Wtn1. Identified were 7707 protein-encoding genes, annotated to different categories such as 805 effectors, 156 CAZymes, 6102 orthologous proteins, and 3180 distinct protein families (PFAMs). Among the effectors, genes like Avra10, Avrk1, Bcg-7, BEC1005, CSEP0105, CSEP0162, BEC1016, BEC1040, and HopI1 closely linked to pathogenesis and virulence were recognized. Transcriptome analysis highlighted abundant proteins associated with RNA processing and modification, post-translational modification, protein turnover, chaperones, and signal transduction. Examining the Environmental Information Processing Pathways in B. graminis f. sp. tritici Wtn1 revealed 393 genes across 33 signal transduction pathways. The key pathways included yeast MAPK signaling (53 genes), mTOR signaling (38 genes), PI3K-Akt signaling (23 genes), and AMPK signaling (21 genes). Additionally, pathways like FoxO, Phosphatidylinositol, the two-component system, and Ras signaling showed significant gene representation, each with 15-16 genes, key SNPs, and Indels in specific chromosomes highlighting their relevance to environmental responses and pathotype evolution. The SNP and InDel analysis resulted in about 3.56 million variants, including 3.45 million SNPs, 5050 insertions, and 5651 deletions within the whole genome of B. graminis f. sp. tritici Wtn1. These comprehensive genome and transcriptome datasets serve as crucial resources for understanding the pathogenicity, virulence effectors, retro-elements, and evolutionary origins of B. graminis f. sp. tritici Wtn1, aiding in developing robust strategies for the effective management of wheat powdery mildew.

Evaluation of Different Treatments on the Management of Black Gram Powdery Mildew Disease Caused by Erysiphe Polygoni (De Candolle)

Black gram (Vigna mungo L.), is one of the most important short duration pulse crops grown in India. Powdery mildew caused by Erysiphe polygoni is a major destructive disease causing drastic economic yield loss upto 50 per cent. In this present study to evaluation of different treatments on the management of powdery mildew on Black gram. Among five mangrove species tested, the leaf extract of Rhiphora apiculata out performed well recording maximum inhibition of conidial germination. In case of fungicides, Azoxystrobin @ 0.1% significantly reduced the conidial germination. The bio-agent Ampelomyces quisqualis was found to be effective at 0.5 per cent concentration against the pathogen. The susceptible variety ADT-3 was raised in both pot and field for management practices. The treatment involving combination of bio-agent and botanical i.e., foliar spraying of A. quisqualis @ 0.5% on 43 DAS AND 53 DAS + foliar spraying of R. apiculata @ 15% on 43 DAS+ 53 DAS recorded minimum per cent disease index in both pot (18.94 %) and field trial (14.50%). The synergistic effect of A. quisqualis and R. apiculata significantly reduces the disease incidence and considerably improve the biometric of blackgram in both pot and field trials are approximately equal to fungicide application.

Management of powdery mildew on chilli through newer fungicides

Management of powdery mildew on chilli through newer fungicides

Induction of defence enzymes for the management of blackgram powdery mildew (Erysiphe polygoni) by Ampelomyces quisqualis

Induction of defence enzymes for the management of blackgram powdery mildew (Erysiphe polygoni) by Ampelomyces quisqualis

Efficacy of strobilurin and triazole fungicides for the management of powdery mildew (Sphaerotheca fuliginea) in summer squash

Efficacy of strobilurin and triazole fungicides for the management of powdery mildew (Sphaerotheca fuliginea) in summer squash

Liquid formulation of Ampelomyces quisqualis AQ003 suppresses powdery mildew of sunflower incited by Golovinomyces cichoracearum

Sunflower (Helianthus annuus L.) is an important oilseed crop grown in India cultivated mainly for its edible oil which is used for culinary purposes. The productivity of sunflower is declined due to biotic stresses, among which powdery mildew caused by Golovinomyces cichoracearum cause huge loss to the farming community. In the present study, an attempt was made to exploit Ampelomyces quisqualis, a pycnidial hyperparasitic fungus for the management of powdery mildew in sunflower. The results revealed that, application of liquid formulation of Ampelomyces quisqualis (0.3 %) was effective in reducing the incidence of powdery mildew of sunflower (9.73 PDI) when compared to control (58.53 PDI) besides increasing the yield. The hyperparasite reduces the incidence of powdery mildew by disrupting the conidiophore and in-turn the mycelial growth. Thus it is concluded that, Ampelomyces quisqualis can be effectively used for the management of powdery mildew of sunflower.

Absorption, translocation, and accumulation of the fungicide triadimefon in Pak choi (Brassica rapa var chinensis), pepper (Capsicum annuum), and cucumber (Cucumis sativus).

Triadimefon is a typical systemic fungicide that is widely used in the management of powdery mildew, rust disease, and southern blight. In this study, we measured fungicide residue to profile its absorption, translocation, and accumulation in three representative vegetable crops (Pak choi, cucumber, and pepper) after over-application. The fungicides were applied through entire-plant spraying (EPS), root-irrigation (RI), and middle-leaf-daubing (MLD). The half-life of triadimefon depends on the application method and plant species. In EPS, the half-life was 5.42 days (Pak choi), 6.86 days (cucumber), and 6.73 days (pepper), while in RI it was 4.39 days (Pak choi), 6.30 days (cucumber), and 5.98 days (pepper). In the EPS treatment, triadimefon is translocated both upward/outside and downward/inner-side from the daubed leaves in all the three vegetable crops. The transfer amount to each organ reached a peak on the 2nd day after fungicide application. The mesophyll of Pak choi exhibited a higher fungicide deposition compared to the petiole. In cucumber and pepper, the leaves demonstrated the highest accumulation of triadimefon (approximately 0.3-0.5 mg·kg-1), followed by stems. Roots and fruits displayed the lowest levels of triadimefon accumulation. Furthermore, triadimefon was found to have an impact on chlorophyll content, root activity, as well as the activity of superoxide dismutase and catalase in Pak choi, indicating its potential as a plant growth regulator. These aforementioned studies provide novel insights for the safe and efficient application of triadimefon in the production of Pak choi, cucumber, and pepper.

Exploring eco-sensitive strategies for effective powdery mildew management in grapevines

Grapevine powdery mildew is one of the most important plant diseases widely affecting crops in many countries. The main aim of the present study was to use Ampelomyces quisqualis isolates to suppress the powdery mildew of grapes under field conditions. The findings revealed a strong correlation between the mycoparasite, Ampelomyces quisqualis and the grape powdery mildew pathogens, suggesting its potential for effective control. The results revealed that a single spray of A. quisqualis @ 2.0 per cent (MDU1) succeeded by two sprays of Trichoderma asperellum @ 2.0 per cent (Tasp,7) were found to be effective against Erysiphe necator. In addition, liquid formulation of A. quisqualis isolate MDU1 (2% w/v) as a foliar spray at 2% containing 2 × 106 spores ml-1 the during initial occurrence of the disease up to three sprayings at 15 days interval was found to be best. Thus, a liquid formulation of A. quisqualis isolate MDU1 proved effective in managing grapes powdery mildew disease under field conditions. The rDNA ITS region of A. quisqualis isolates was analyzed at the molecular level, and the resulting sequences were subjected to GC-MS analysis. The secondary metabolite identification using GC-MS revealed the presence of antimicrobial compounds, including squalene with the highest peak of 4.643 percent, octadecanoic acid with 3.862 percent, tetradecanoic acid with 3.600 percent, and 9,12-octadecadienoic acid (Z,Z) with 1.451 percent. These bioactive compounds revealed by GC-MS analysis in crude extracts of A. quisqualis had a stronger antifungal activity against E. necator.

Effective management of powdery mildew in cantaloupe plants using nighttime applications of UV light.

Ultraviolet light at wavelengths from 254 to 283 nm has been reported to effectively suppress powdery mildews in several crops, including some cucurbits. Its use to suppress powdery mildew (Podosphaera xanthii) specifically in cantaloupe has not been previously reported. We evaluated the foregoing technology in cantaloupe fields for suppression of powdery mildew and possible effects on plant growth, and yield. In a controlled laboratory study, greenhouse-grown cantaloupe plants were exposed to a gradient of UV-C (254 nm) doses during darkness, and the effects upon powdery mildew development and the plant were evaluated. We also evaluated the efficacy of nighttime applications of UV-C at 100 and 200 J/m2 against powdery mildew on adaxial leaf surfaces in greenhouse, high-tunnel and open-field plantings. UV-C at the foregoing doses reduced sporulation and germination of conidia P. xanthii without damaging plants. On cantaloupe seedlings in the greenhouse, disease severity was equivalently suppressed at all doses and frequencies of applications of the light. In high-tunnel and open-field experiments, the most effective control of powdery mildew was provided by UV-C applied at 200 J/m2 twice every week, where suppression provided by UV-C was generally equal to and sometimes better than the fungicide treatment. The foregoing UV-C dose and frequency of application also provided the highest yield under field conditions, indication that UV-C treatment is a promising technology for commercially-relevant suppression of powdery mildew on cantaloupe in a variety of growing systems.

Occurrence of resistance in field populations of Erysiphe necator to QoI, azanaphthalene and aryl-phenyl-ketone fungicides in Serbia

The objective of this study was to investigate whether the sensitivity of E. necator populations to several important fungicide groups has changed in Serbia. Field trials, bioassays, and molecular tests were conducted from 2019 to 2022. Samples were collected from commercial, experimental and extensive vineyards. Low efficacy of QoIs, azanaphthalenes and aryl-phenyl-ketones was observed in the field trials. A total of 110 isolates were analyzed by qPCR for the presence of the G143A mutation. The mutation was positively detected in 61.8% of the isolates, therefore isolates containing >95% of the G143A allele were QoI-resistant in bioassays. Contrary, QoI-sensitive isolates contained <5% of the G143A allele. Of the 54 isolates tested in bioassays, 46 grew significantly at the recommended concentration, whereas 36 were able to grow at a fourfold higher concentration of quinoxyfen. Proquinazid showed more significant inhibition than quinoxyfen, suggesting that there is no cross-resistance between these two members of the azanaphthalene group. Unsatisfactory effect of metrafenone and pyriofenone at recommended concentrations was observed in 29 of 41 isolates. These isolates grew readily at four times higher concentrations of metrafenone and pyriofenone, indicating the cross-resistance between them. Overall, the results of this study suggest that resistance to QoIs has developed and is widespread in commercial vineyards, requiring growers to exclude them completely from powdery mildew management. The performance of proquinazid in the field was not affected, making it suitable for powdery mildew control. Special attention and extensive monitoring should be directed to metrafenone and pyriofenone, as cross-resistance has been found at certain sites where they have been used intensively over the past decade.

Management of Powdery Mildew Caused by Erysiphe betae in Sugar Beet using Algal Products

Management of Powdery Mildew Caused by Erysiphe betae in Sugar Beet using Algal Products

Strategic Management of Powdery Mildew of Grapes Using Fungicides and Bio-Control Agents

The study was carried out at ICAR-NRCG, Pune, Maharashtra, India during November–February of 2019–2020 and 2020–2021 to evaluate the bio-efficacy of fungicides and biocontrol agents and level of tolerance against powdery mildew of grapes. Total 18 treatments categorised into three groups were taken into account. Three groups viz. fungicides, biocontrol agents (Bacillus licheniformis, Trichoderma afroharzianum, Ampelomyces quisqualis) along with metrafenone and commercial formulations of biocontrol agents were analysed for disease control. A total of five applications of each treatment were made during the growing season. Results showed that, in case of Group I (registered fungicides), Hexaconazole 5 EC @ 1 ml l-1/ Difenoconazole 25 EC @ 0.5 ml l-1/Myclobutanil 10 WP @ 0.4 g l-1/Two sprays of sulphur @ 2 g l-1 was most effective in controlling the disease. In case of pure culture, Trichoderma afroharzanium had proved to be most effective in the control of powdery mildew when sprayed in alteration with Metrafenone. In Group III, alternate applications of commercial formulations of Bacillus subtilis (2 ml l-1), Trichoderma viridae (2 g l-1), Ampelomyces quisqualis (5 ml l-1) and sulphur (2 g l-1) was most effective in controlling the disease. It was concluded that the application of bio-control agents in alternation with chemical fungicides controlled the disease effectively.

Evaluation of the sensitivity of Podosphaera xanthii to several fungicides for management of powdery mildew on squash in Florida

Cucurbit powdery mildew caused by Podosphaera xanthii is a major challenge to cucurbit production worldwide. In the United States, the fungus has become resistant to fungicides in FRAC Groups 1, 3, U6, 7, 11, and 13, however the extent of this resistance is not known in the Florida population. Commercially labeled fungicides, thiophanate-methyl (Topsin 70WDG), cyflufenamid (Torino), flutriafol (Rhyme), quinoxyfen (Quintec), and myclobutanil (Rally 40 WSP), were selected to screen for sensitivity against locally obtained isolates under laboratory, greenhouse, and field conditions. Laboratory and greenhouse assessments of disease severity and control were made after a single application of each fungicide, while field trial assessments were made after weekly applications. Quinoxyfen, myclobutanil, cyflufenamid, and flutriafol gave adequate control of powdery mildew, while thiophanate-methyl failed to control P. xanthii. No formulation was successful in preventing the establishment and sporulation of P. xanthii at the maximum or near-maximum labeled field rate under laboratory, greenhouse, and field conditions. Further research is required to monitor the Florida population for early detection of fungicide resistance, to establish new effective fungicidal concentrations, and to optimize fungicide application regimes.

RNAi Technology: A New Path for the Research and Management of Obligate Biotrophic Phytopathogenic Fungi.

Powdery mildew and rust fungi are major agricultural problems affecting many economically important crops and causing significant yield losses. These fungi are obligate biotrophic parasites that are completely dependent on their hosts for growth and reproduction. Biotrophy in these fungi is determined by the presence of haustoria, specialized fungal cells that are responsible for nutrient uptake and molecular dialogue with the host, a fact that undoubtedly complicates their study under laboratory conditions, especially in terms of genetic manipulation. RNA interference (RNAi) is the biological process of suppressing the expression of a target gene through double-stranded RNA that induces mRNA degradation. RNAi technology has revolutionized the study of these obligate biotrophic fungi by enabling the analysis of gene function in these fungal. More importantly, RNAi technology has opened new perspectives for the management of powdery mildew and rust diseases, first through the stable expression of RNAi constructs in transgenic plants and, more recently, through the non-transgenic approach called spray-induced gene silencing (SIGS). In this review, the impact of RNAi technology on the research and management of powdery mildew and rust fungi will be addressed.

Refining Management of Apple Powdery Mildew in New York State with Weather-Based Fungicide Application Timing Programs.

In the absence of durable host resistance among commercial cultivars, chemical management continues to be an essential component of disease control in apple production. Apple powdery mildew, caused by the ascomycete Podosphaera leucotricha, is largely managed with regular fungicide applications from the host phenological stages of tight cluster to terminal bud growth set, with applications typically being made in a prophylactic manner irrespective of existing disease pressure. Here we evaluated two management programs that aligned fungicide applications to specific weather thresholds conducive to powdery mildew development using a rotation of single-site fungicides and sulfur. In three separate orchards among four cultivars, we compared powdery mildew disease progression over the growing season for each of the weather factor-based programs and a typical calendar-based application program. In each year of the trial, we found that management programs with weather-based fungicide applications provided levels of disease control similar to the calendar program but required 50 to 83.3% fewer mildew-specific fungicide applications throughout the growing season. Our results provide a framework with which to evaluate future weather-based management programs for apple powdery mildew management. This knowledge could be implemented in the creation of a powdery mildew disease management decision support system to better inform and aid fungicide application programs for continued sustainable apple production in the northeast United States.