Publications

A Rapid Glove-Based Inoculum sampling Technique to Monitor Erysiphe necator in Commercial Vineyards

Abstract: Information on the presence and severity of grape powdery mildew (GPM), caused by Erysiphe necator, has long been used to guide management decisions. While recent advances in the available molecular diagnostic assays and particle samplers have made monitoring easier, there is still need for more efficient field collection of E. necator. The use of vineyard worker gloves worn during canopy manipulation as a sampler (glove swab) of E. necator was compared with samples identified by visual assessment with subsequent molecular confirmation (leaf swabs) and airborne spore samples collected by rotating-arm impaction traps (impaction traps). Samples from U.S. commercial vineyards in Oregon, Washington, and California were analyzed using two TaqMan qPCR assays targeting the internal transcribed spacer regions or cytochrome b gene of E. necator. Based on qPCR assays, visual disease assessments misidentified GPM up to 59% of the time with a higher frequency of misidentification occurring earlier in the growing season. Comparison of the aggregated leaf swab results for a row (n=915) to the row’s corresponding glove swab had 60% agreement. The latent class analysis (LCA) indicated that glove swabs were more sensitive than leaf swabs in detecting E. necator presence. The impaction trap results had 77% agreement to glove swabs (n=206) taken from the same blocks. The LCAs estimated that the glove swabs and impaction trap samplers varied each year in which was more sensitive for detection. This likely indicates that these methods have similar levels of uncertainty and provide equivalent information. Additionally, all samplers, once E. necator was detected, were similarly sensitive and specific for detection of the A-143 resistance allele. Together, these results suggest that glove swabs are a viable sampling method for monitoring the presence of E. necator and, subsequently, the G143A amino acid substitution associated with resistance to quinone outside inhibitor fungicides in vineyards. Glove swabs could significantly reduce sampling costs due to the lack of need for specialized equipment, and time required for swab collection and processing. . Lowder, S.R.^, T. M. Neill, A.B. Peetz, T.M. Miles, M.M. Moyer, C. Oliver⁺, I. Stergiopoulos, S. Ding, and W. Mahaffee. 2023. A Rapid Glove-Based Inoculum Sampling Technique to Monitor Erysiphe necator in Commercial Vineyards. Plant Dis. First Look. DOI: 10.1094/PDIS-02-23-0216-RE

Development of a PNA-LNA-LAMP Assay to Detect a SNP Associated with QoI Resistance in Erysiphe necator

Abstract: The repetitive use of quinone outside inhibitor fungicides (QoIs, strobilurins; Fungicide Resistance Action Committee (FRAC) 11) to manage grape powdery mildew has led to development of resistance in Erysiphe necator. While several point mutations in the mitochondrial cytochrome b gene are associated with resistance to QoI fungicides, the substitution of glycine to alanine at codon 143 (G143A) has been the only mutation observed in QoI–resistant field populations. Allele-specific detection methods such as digital droplet PCR and TaqMan probe-based assays can be used to detect the G143A mutation. In this study, a peptide nucleic acid-locked nucleic acid mediated loop-mediated isothermal amplification (PNA–LNA–LAMP) assay consisting of an A-143 reaction and a G-143 reaction, was designed for rapidly detecting QoI resistance in E. necator. The A-143 reaction amplifies the mutant A-143 allele faster than the wild-type G-143 allele, while the G-143 reaction amplifies the G-143 allele faster than the A-143 allele. Identification of resistant or sensitive E. necator samples was determined by which reaction had the shorter time to amplification. Sixteen single-spore QoI–resistant and sensitive E. necator isolates were tested using both assays. Assay specificity in distinguishing the single nucleotide polymorphism (SNP) approached 100% when tested using purified DNA of QoI-sensitive and –resistant E. necator isolates. This diagnostic tool was sensitive to one-conidium equivalent of extracted DNA with an R2 value of 0.82 and 0.87, for G-143 and A-143 reactions, respectively. This diagnostic approach was also evaluated against a TaqMan probe-based assay using 92 E. necator samples collected from vineyards. The PNA–LNA–LAMP assay detected QoI resistance in ≤30 minutes and showed 100% agreement with the TaqMan probe-based assay (≦1.5 hours) for the QoI-sensitive and –resistant isolates. There was 73.3% agreement with the TaqMan probe-based assay when samples had mixed populations with both G-143 and A-143 alleles present. Validation of the PNA–LNA–LAMP assay was conducted in three different laboratories with different equipment. The results showed 94.4% accuracy in one laboratory and 100% accuracy in two other laboratories. The PNA–LNA–LAMP diagnostic tool was faster and required less expensive equipment relative to the previously developed TaqMan probe-based assay, making it accessible to a broader range of diagnostic laboratories for detection of QoI resistance in E. necator. This research demonstrates the utility of the PNA-LANA-LAMP for discriminating SNPs from field samples and its utility for point-of-care monitoring of plant pathogen genotypes.  Sharma, M., T. Neill, H-C.Yang, C. Oliver, W. Mahaffee, R. Naegele, M.M. Moyer, and T.D. Miles. 2023. Development of a Competitive PNA-LNA-LAMP Assay to Detect a SNP Associated with QoI Resistance in Erysiphe necator. Plant Disease – First Look. DOI: 10.1094/PDIS-09-22-2027-RE

Facing Fungicide Resistance in Grape Production: A Game Theoretic Approach

Abstract: Fungicide resistance is a serious problem for agriculture today. This analysis provides additional insight into the strategic behavior of farmers when their fungicide use generates a negative intertemporal production externality in the form of fungicide resistance. We find that when farmers encounter this type of externality, they choose fungicide levels that exacerbate fungicide resistance. We examine a compensation mechanism in which a farmer reduces fungicide use in exchange for a transfer. This mechanism reduces fungicide use; however, misinformation about the severity of fungicide resistance generates distortions. We find that one-sided misinformation could lead a farmer to choose socially optimal fungicide levels, which makes the compensation mechanism less necessary. In addition, we show that when both farmers are misinformed, the mechanism could lead farmers to choose fungicide levels below the socially optimal level depending on their pessimistic beliefs about the severity of fungicide resistance. Pardini, C.A., and A. Espínola-Arredondo. 2023. Facing Fungicide Resistance in Grape Production:  A Game Theoretic Approach. Canadian Journal of Agricultural Economics.  DOI: 10.1111/cjag.12334

Identification of Putative SDHI Target Site Mutations in the SDHB, SDHC, and SDHD Subunits of the Grape Powdery Mildew Pathogen Erysiphe necator

Abstract: Succinate dehydrogenase inhibitors (SDHIs) are fungicides used in control of numerous fungal plant pathogens, including Erysiphe necator, the causal agent of grapevine powdery mildew (GPM). Here, the sdhb, sdhc, and sdhd genes of E. necator were screened for mutations that may be associated with SDHI resistance. GPM samples were collected from 2017 to 2020 from the U.S. states of California, Oregon, Washington, and Michigan, and the Canadian province of British Columbia. Forty-five polymorphisms were identified in the three sdh genes, 17 of which caused missense mutations. Of these, the SDHC-p.I244V substitution was shown in this study to reduce sensitivity of E. necator to boscalid and fluopyram, whereas the SDHC-p.G25R substitution did not affect SDHI sensitivity. Of the other 15 missense mutations, the SDHC-p.H242R substitution was shown in previous studies to reduce sensitivity of E. necator toward boscalid, whereas the equivalents of the SDHB-p.H242L, SDHC-p.A83V, and SDHD-p.I71F substitutions were shown to reduce sensitivity to SDHIs in other fungi. Generally, only a single amino acid substitution was present in the SDHB, SDHC, or SDHD subunit of E. necator isolates, but missense mutations putatively associated with SDHI resistance were widely distributed in the sampled areas and increased in frequency over time. Finally, isolates that had decreased sensitivity to boscalid or fluopyram were identified but with no or only the SDHC-p.G25R amino acid substitution present in SDHB, SDHC, and SDHD subunits. This suggests that target site mutations probably are not the only mechanism conferring resistance to SDHIs in E. necator. Citation:  Stergiopoulos, I., N. Aoun, Q. van Huynh, T. Neill, S. Lowder, C. Newbold, M.L. Cooper, S. Ding, M.M. Moyer, T.D. Miles, C.L. Oliver, J.R. Urbez-Torres, and W. Mahaffee. 2022. Identification of Putative SDHI Target-Site Mutations in the SDHB, SDHC, and SDHD Subunits of the Grape Powdery Mildew Pathogen Erysiphe necator. Plant Disease 106: 2310-2320. DOI: 10.1094/PDIS-09-21-1993-RE

Momentum and turbulent transport in sparse, organized vegetative canopies

Abstract

A large-eddy simulation study was performed to characterize turbulence in sparse, row-oriented canopies. This was accomplished by simulating a set of heterogeneous row-oriented canopies with varying row vegetation density and spacing. To determine the effects of heterogeneity, results were compared to horizontally homogeneous canopies with an equivalent ‘effective’ leaf area index. By using a proper effective leaf area index, plane-averaged mean velocities and bulk scaling parameters contained only small errors when heterogeneity was ignored. However, many cases had significantly larger second- and third-order velocity moments in the presence of heterogeneity. Some heterogeneous canopies also contained dispersive fluxes in the lower canopy that were over 20 % as large as the turbulent flux. Impacts of heterogeneity were most pronounced in the cases of large row leaf area density and widely spaced rows. Despite the substantial amount of open space in the sparse canopies, vertical velocity skewness and quadrant-hole analysis indicated that the flow behaved predominantly as a canopy layer even though integral length scales at the canopy top no longer followed mixing-layer scaling. This was supported by the fact that similar composite-averaged coherent structures could be readily identified in both the heterogeneous and homogeneous canopies. Heterogeneity had an effect on coherent structures, in that structure detection events were most likely to occur just upwind of the vegetation rows. In simulations with large row spacing, these structures also penetrated deeper into the canopy when compared to the equivalent homogeneous canopy.

Citation: Torkelson, G., T. Price, and R. Stoll. 2022. Momentum and Turbulent Transport in Sparse, Organized Vegetative Canopies. Boundary-Layer Meteorology. DOI: 10.1007/s10546-012-9796-4

Cooperation and compensation to mitigate fungicide resistance

Abstract

We evaluated grape growers’ awareness of fungicide resistance and willingness to adjust fungicide use practices to mitigate this problem in vineyards. We conducted a pilot study surveying a small group of United States grape growers to assess their knowledge about fungicide resistance and willingness to adjust fungicide use based in the impact that use had on their own farm, and their neighboring farms’ profits. We found that though growers are generally willing to adjust their fungicide use practices if it assisted with the mitigation of resistance, they were less willingness to do so when that adjustment would negatively impact their profits. We also evaluated their willingness to adjust their fungicide use when lost profits were remediated with compensation. To understand the relationship between their willingness to change their practices with compensation and their baseline willingness to do so (without compensation), we conducted a logistic regression. Given the small sample inference, we used bootstrapped estimates and observed an increase on growers’ willingness to adjust their fungicide use when compensation is available. Our analysis underscores the importance of monetary compensations as an incentive tool to fight against fungicide resistance.

Citation:

Pardini, C., A. Espínola-Arredondo, and M. Moyer. 2022. Cooperation and Compensation to Mitigate Fungicide Resistance. Am. J. Enol. Vitic. 73: in press. DOI: 10.5344/ajev.2022.21052

Identification of SDHI target-site mutations in the SDHB, SDHC, and SDHD subunits of the grape powdery mildew pathogen Erysiphe necator

Abstract

Succinate dehydrogenase inhibitors (SDHIs) are fungicides used in control of numerous fungal plant pathogens, including of Erysiphe necator, the causal agent of grapevine powdery mildew (GPM). Here, the sdhb, sdhc, and sdhd genes of E. necator were screened for mutations that may associate with SDHI resistance. GPM samples were collected from 2017 to 2020 from the U.S. states of California, Oregon, Washington and Michigan, and the Canadian province of British Columbia. Forty-five polymorphisms were identified in the three sdh genes, 17 of which caused missense mutations. Of these, the SDHC-p.I244V substitution was shown in this study to reduce sensitivity of E. necator to boscalid and fluopyram, whereas the SDHC-p.G25R substitution did not affect SDHI sensitivity. Of the other 15 missense mutations, the SDHC-p.H242R substitution was shown in previous studies to reduce sensitivity of E. necator towards boscalid, whereas the equivalents of the SDHB-p.H242L, SDHC-p.A83V, and SDHD-p.I71F substitutions were shown to reduce sensitivity to SDHIs in other fungi. Generally, only a single amino acid substitution was present in the SDHB, SDHC, or SDHD subunit of E. necator isolates but missense mutations putatively associated with SDHI resistance were widely distributed in the sampled areas and increased in frequency over time. Finally, isolates that had decreased sensitivity to boscalid or fluopyram were identified but with no or only the SDHC-p.G25R amino acid substitution present in SDHB, SDHC, and SDHD subunits. This suggests that target-site mutations is likely not the only mechanism conferring resistance to SDHIs in E. necator.

Citation:  Stergiopoulos, I., N. Aoun, Q. van Huynh, T. Neill, S. Lowder, C. Newbold, M. Cooper, S. Ding, M. Moyer, T. Miles, C. Oliver, J. Úrbez-Torres, and W. Mahaffee. 2022. Identification of SDHI target-site mutations in the SDHB, SDHC, and SDHD subunits of the grape powdery mildew pathogen Erysiphe necator. Plant Disease First Look. DOI: 10.1094/PDIS-09-21-1993-RE

Development and evaluation of an isolated-tree flow model for neutral-stability conditions

Abstract

Citation: Margairaz, F., H. Eshagh, A. Hayati, E. Pardyjak and R. Stoll. 2022. Development and evaluation of an isolated-tree flow model for neutral-stability conditions. Urban Climate. 42:101083. DOI: 10.1016/j.uclim.2022.101083

Allele-specific detection methods for QoI fungicide resistant Erysiphe necator in vineyards

Abstract

Grapevine powdery mildew (GPM), caused by the fungus Erysiphe necator, is a constant threat to worldwide production of grapes, requiring repeated use of fungicides for management. The frequent fungicide applications have resulted in resistance to commonly used quinone outside inhibitor (QoIs) fungicides and the resistance is associated with single nucleotide polymorphisms (SNPs) in the mitochondrial cytochrome b gene (cytb). In this study, we attempted to detect the most common SNP causing a glycine to alanine substitution at amino acid position 143 (i.e., G143A) in the cytb protein, to track this resistance using allele-specific TaqMan probe- and digital droplet PCR-based assays. Specificity and sensitivity of these assays showed that these two assays could discriminate SNPs and were effective on mixed samples. These diagnostic assays were implemented to survey E. necator samples collected from leaf and air samples from California and Oregon grape growing regions. Sequencing of PCR amplicons and phenotyping of isolates also revealed that these assays accurately detected each allele (100% agreement) and there was an absolute agreement between the presence/absence of the G143A mutation and resistance to QoIs in the E. necator sampled. These results indicate that the developed diagnostic tools will help growers make informed decisions on fungicide selections and applications, which in turn, will facilitate GPM disease management and improve grape production systems.

Citation: Miles, T.D., Neill, T.M., Colle, M., Warneke, B, Robinson, G., Sterigiopoulus, I. and Mahaffee, W.F. 2021. Allele-specific detection methods for QoI fungicide resistant Erysiphe necator in vineyards. Plant Disease 105: 175-182.

Utilizing dynamic parallelism in CUDA to accelerate a 3D red-black successive over relaxation wind-field solver

Abstract

QES-Winds is a fast-response wind modeling platform for simulating high-resolution mean wind fields for optimization and prediction. The code uses a variational analysis technique to solve the Poisson equation for Lagrange multipliers to obtain a mean wind field and GPU parallelization to accelerate the numerical solution of the Poisson equation. QES-Winds benefits from CUDA dynamic parallelism (launching the kernel from the GPU) to speed up calculations by a factor of 128 compared to the serial solver for a domain with 145 million cells. The dynamic parallelism enables QES-Winds to calculate mean velocity fields for domains with sizes of 10 km² and horizontal resolutions of 1-3 m in under 1 min. As a result, QES-Winds is a numerical code suitable for computing high-resolution wind fields on large domains in real time, which can be used to model a wide range of real-world problems including wildfires and urban air quality.

Citation: Bozorgmehr, B., Willemsen, P., Gibbs, J., Stoll, R., Kim, J., & Pardyjak, E. 2021. Utilizing dynamic parallelism in CUDA to accelerate a 3D red-black successive over relaxation wind-field solver. Environmental Modelling & Software: with Environment Data News., 137.

Assessing the United States grape industry’s understanding of fungicide resistance mitigation practices

Abstract

In 2019, a national survey of 252 members of the USA grape industry from 20 USA states assessed knowledge perception of fungicide resistance management, application of that knowledge to vineyard practices, and knowledge acquisition sources. Overall, respondents demonstrated clear understanding of resistance management practices. The specific distribution of responses was influenced by the respondent’s job role, duration of industry experience, and their farming operation size. Nationally, respondents were moderately familiar with the acronym FRAC (Fungicide Resistance Action Committee), with nearly 75% indicating they could identify the FRAC code of a fungicide. They felt moderately competent they could design a fungicide program that adhered to resistance management principles. Respondents identified fungicide resistance as a serious problem nationally, and as a moderate problem in their own vineyards. They ranked practices that include rotating fungicides of different FRAC codes, avoiding multiple sequential applications of the same trade name or FRAC code, tank mixing with different FRAC codes, using multisite products in a spray program, routine sprayer maintenance and calibration, and good canopy management as very to extremely important in managing fungicide resistance; whereas practices such as rotating between trade names and tank mixing different trade names ranked slightly important. Respondents identified university-based Extension programs as the primary information resource for fungicide efficacy and fungicide stewardship (resistance management). In order to maximize potential impact, these results suggest that future educational efforts should be aimed at improving practices for fungicide resistance stewardship and should align with the knowledge base and demographic factors of the target audience particularly their job role, experience and size of operation.

Citation: Oliver, C., M. Cooper, M. Lewis-Ivey, P. Brannen, T. Miles, W. Mahaffee, and M. Moyer. 2021. Assessing the United States grape industry’s understanding of fungicide resistance mitigation practices. Am. J. Enol. Vitic.72 (2) 181-193.

The mitochondrial genome of the grape powdery mildew pathogen Erysiphe necator is intron rich and exhibits a distinct gene organization

Abstract

Powdery mildews are notorious fungal plant pathogens but only limited information exists on their genomes. Here we present the mitochondrial genome of the grape powdery mildew fungus Erysiphe necator and a high-quality mitochondrial gene annotation generated through cloning and Sanger sequencing of full-length cDNA clones. The E. necator mitochondrial genome consists of a circular DNA sequence of 188,577 bp that harbors a core set of 14 protein-coding genes that are typically present in fungal mitochondrial genomes, along with genes encoding the small and large ribosomal subunits, a ribosomal protein S3, and 25 mitochondrial-encoded transfer RNAs (mt-tRNAs). Interestingly, it also exhibits a distinct gene organization with atypical bicistronic-like expression of the nad4L/nad5 and atp6/nad3 gene pairs, and contains a large number of 70 introns, making it one of the richest in introns mitochondrial genomes among fungi. Sixty-four intronic ORFs were also found, most of which encoded homing endonucleases of the LAGLIDADG or GIY-YIG families. Further comparative analysis of five E. necator isolates revealed 203 polymorphic sites, but only five were located within exons of the core mitochondrial genes. These results provide insights into the organization of mitochondrial genomes of powdery mildews and represent valuable resources for population genetic and evolutionary studies.

Citation: Zaccaron, A., De Souza, J., and Stergiopoulos, I. 2021. The mitochondrial genome of the grape powdery mildew pathogen Erysiphe necator is intron rich and exhibits a distinct gene organization. Scientific Reports. 11:13924.

Characterization of the mitochondrial genomes of three powdery mildew pathogens reveals remarkable variation in size and nucleotide composition

Abstract

Powdery mildews comprise a large group of economically important phytopathogenic fungi. However, limited information exists on their mitochondrial genomes. Here, we assembled and compared the mitochondrial genomes of the powdery mildew pathogens Blumeria graminis f. sp. tritici, Erysiphe pisi, and Golovinomyces cichoracearum. Included in the comparative analysis was also the mitochondrial genome of Erysiphe necator that was previously analyzed. The mitochondrial genomes of the four Erysiphales exhibit a similar gene content and organization but a large variation in size, with sizes ranging from 109800 bp in B. graminis f. sp. tritici to 332165 bp in G. cichoracearum, which is the largest mitochondrial genome of a fungal pathogen reported to date. Further comparative analysis revealed an unusual bimodal GC distribution in the mitochondrial genomes of B. graminis f. sp. tritici and G. cichoracearum that was not previously observed in fungi. The cytochrome b (cob) genes of E. necator, E. pisi, and G. cichoracearum were also exceptionally rich in introns, which in turn harboured rare open reading frames encoding reverse transcriptases that were likely acquired horizontally. Golovinomyces cichoracearum had also the longest cob gene (45 kb) among 703 fungal cob genes analysed. Collectively, these results provide novel insights into the organization of mitochondrial genomes of powdery mildew pathogens and represent valuable resources for population genetics and evolutionary studies.

Citation: Zaccaron, A., and Stergiopoulos, I. 2021. Characterization of the mitochondrial genomes of three powdery mildew pathogens reveals remarkable variation in size and nucleotide composition. Microbial Genomics. 7:000720.

Facing fungicide resistance in grape production: A game theoretic approach

Abstract: Fungicide resistance developed by pathogens that grapes are susceptible to is problematic for the industry today. We provide further insight into the strategic behavior of grape growers when their choices of fungicide levels generate a negative intertemporal production externality in the form of fungicide resistance. We find that when growers encounter this type of externality, the noncooperative fungicide level is higher than the socially optimal level. We examine a compensation mechanism designed to ameliorate fungicide resistance and find that it induces the socially optimal level; however, misinformation about the severity of the fungicide resistance generates distortions. The results suggest that the information available to growers about fungicide resistance is essential for its mitigation with the proposed compensation mechanism. In particular, we find that if the misinformed grower considers fungicide resistance to be relatively
mild, then it is preferable that the misinformed grower has the compensating role .

Citation: Pardini, C., A. Espinola-Arredondo. 2020. Facing Fungicide Resistance in Grape Production: A Game Theoretic Approach. AgEcon .DOI: 10.22004/ag.econ.304309

• Good to Know: Dialing in disease control. Best practices for fungicide stewardship. – Good Fruit Grower
• Early Season Scouting for Grape Powdery Mildew – Good Fruit Grower
• Managing Fungicide Resistance in the Vineyard – American Vineyard
• Good to Know: Why some seasons are worse for powdery mildew – Good Fruit Grower

• Warres, B., K. Johnson, K. Busher, C. Cameron, P.M. Brannen, D. Rogers, R. Covington, W. Mahaffee, and T. Neil. 2021. Fungicide comparisons for powdery mildew management in a fungicide-resistant Erysiphe necator population, 2020. Plant Dis. Mgmt. Rep.15:PF012
• Warres, B., K. Johnson, K. Busher, C. Cameron, P.M. Brannen, D. Rogers, R. Covington, W. Mahaffee, and T. Neil. 2021. Assessment of interactions between sulfur and DMI fungicides to control powdery mildew in the presence of a DMI-resistant Erysiphe necator population in Georgia, 2020. Plant Dis. Mgmt. Rep.15:PF013
• Warres, B., K. Johnson, K. Busher, C. Cameron, P.M. Brannen, D. Rogers, R. Covington, W. Mahaffee, and T. Neil. 2021. Efficacy of DMI (FRAC 3) fungicides for control of powdery mildew in a DMI-tolerant Erysiphe necator population, 2020. Plant Dis. Mgmt. Rep.15:PF014
• Warres, B., S. Breeden, J. Winkles, P. Severns, P. Brannen, D. Rogers, R. Covington, W. Mahaffee, and T. Neill. 2020. Fungicide comparisons for powdery mildew management in a fungicide-resistant Erysiphe necator population, 2019. Plant Dis. Mgmt. Rep.14:PF014.
• Warres, B., S. Breeden, J. Winkles, P. Severns, P.M. Brannen, D. Rogers, R. Covington, W. Mahaffee, and T. Neill. 2020. Efficacy of sulfur and myclobutanil combinations for control of grapevine powdery mildew in Georgia, 2019. Plant Dis. Mgmt. Rep.14:PF015.

Published Conference Proceedings

9^th International Workshop on Grapevine Downy and Powdery Mildews (GDPM 2022)

Conference Proceedings: https://www.bio-conferences.org/articles/bioconf/abs/2022/09/contents/contents.html

• Assessment of QoI and CAA fungicide resistance of Plasmopara viticola populations in vineyards of the Great Lakes region in the United States of America. Authors: N. Sharma, L. Heger, D. Combs, K. Gold and T. D. Miles
• Bridging the gap between powdery mildew genomics and valuable culturing methods of Erysiphe necator and Podosphaera aphanis. Authors: S. Thompson, T. Neill, W. Mahaffee and T. Miles
• Advances in molecular and optical detection strategies for grape downy mildew. Authors: L. Heger, F. Martin, N. Sharma and T. D. Miles
• Influence of sustainability programs on fungicide stewardship practices in Pacific Northwest United States vineyards. Authors: C.L. Oliver and M.M. Moyer
• Improving Confidence and Understanding of Fungicide Program Design in USA Grape Growers Through Peer-Interactive Extension Programming. Author: M.M. Moyer
• Rapid sampling technique to monitor Erysiphe necator more effective than visual scouting. Authors: Sarah R. Lowder, Tara M. Neill, Timothy M. Miles, Michelle M. Moyer, Charlotte Oliver, Shunping Ding and Walter F. Mahaffee