Progress 09/01/15 to 08/31/19
Outputs
Target Audience:Our stakeholders are cucurbit growers, pest management advisors, consultants, extension educators, agricultural industry personnel, and beekeepers throughout the Northeast and mid-Atlantic regions and other locations with similar production systems. Within our research group, we all have partial extension appointments and regularly teach these stakeholder groups. Our project has been successfully initiated and as it progresses, it will improve in-season disease management decisions. It will enable growers to effectively manage pests while reducing pollinator exposure to key fungicides and our results will be incorporated into existing IPM programs that include the use of crop rotation, host resistance (when available), scouting, and disease and forecasting tools. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?One-on-one discussions were held with various student interns regarding the purpose of the established trial to evaluate the use of alternative fungicide programs that reduce the reliance on chlorothalonil for the management of powdery mildew on pumpkin. Research station visitors learned about the approved goals and research outcomes. General concepts of the project and the use of bioassays to monitor and document fungicide resistance was included in course lectures for the Plant Science capstone Integrated Pest Management course at Pennsylvania State University. One graduate student was supported through this grant. How have the results been disseminated to communities of interest?The research results have been disseminated at several regional vegetable grower meetings/ conferences including the Mid-Atlantic Fruit and Vegetable Convention in Hershey, PA, University of Delaware Ag Week, and the New Jersey Agricultural Convention and Trade Show, see below. Extension news articles across the region also presented information on the project. In New York, information about CDM occurrence in the eastern US and fungicide recommendations were provided to Long Island growers in the weekly Long Island Fruit & Vegetable Update during the 2019 growing season. In Maryland andDelaware, updates on CDM occurrence were published in the University of Delaware Weekly Crop Update, and the University of Maryland Extension Fruit and Vegetable News. A research update article (Jones, J.G., and Everts, K.L., 2018. Early Detection and Control of Downy Mildew on Cucurbits) summarized the project findings in University of Maryland Extension, Vegetable and Fruit Headline News, Special Research Edition. Locally, results were also disseminated throughout the season through one-on-one meetings and conversations with growers, at summer twilight meetings and through regular extensionn activities (see extension presentation list below). Information about fungicides and fungicide resistance is also frequently included in disease alerts and extension newsletter articles with a link to the updated cucurbit powdery and downy mildew fungicide resistance management guidelines (PHP 2018 19:34-36). Hardcopies of the recommendations table were distributed at educational kiosks at eight produce auctions across Pennsylvania to provide resources to the primarily Anabaptist community that does not access information electronically. Extension presentations were given across our multi-state area that included information about project results and recommendations based on these results. 1. Vegetable disease update: What have we been seeing in 2019? July 31, 2019. Kutztown Produce Auction Vegetable Meeting. Fleetwood, PA. 2. Vegetable disease update. March 7, 2019. Small Fruit and Vegetable Meeting - Montgomery County. Worcester, PA. 3. Vine crop disease management in wet year. January 31, 2019. Mid-Atlantic Fruit and Vegetable Convention. Hershey Lodge & Convention Center, Hershey, PA. 4. Vine crop disease management in wet years. January 25, 2019. Juniata County Plain-sect Auction Growers Meeting. Thompsontown, PA. 5. Vegetable disease management: Surviving a wet year. January 24, 2019. Northeast Vegetable Growers Meeting. Newton Ransom Fire Company, Clarks Summit, PA. 6. Vegetable pathology research projects. September 6, 2018. Plant Science Day. Riverhead, NY. 7. Thirty years of research helping farmers manage diseases of cucurbits. September 26, 2018. Watermelon and Melon Training. Zhengzhou, China. 8. What's new about downy mildews and their management in basil and other crops. January 1, 2019. 2019 Long Island Agricultural Forum. Sustainable Session. Speonk, NY. 9. Key facts to know about plant diseases occurring in the region and their management. January 10, 2019. 2019 Long Island Agricultural Forum. Beginning Farmer Session. Speonk, NY. 10. Successfully managing diseases in 2019 based on what was learned in 2018. January 10, 2019. 2019 Long Island Agricultural Forum. Vegetable Session. Speonk, NY. 11. Managing mildews and phytophthora blight successfully in 2019. January 15, 2019. 2019 Empire State Producers Expo. Vine Crops Session. Syracuse, NY. 12. Managing powdery mildew on cucurbits and tunnel tomatoes. January 21, 2019. Vermont Vegetable and Berry Growers Association Annual Meeting. Fairlee, VT. 13. Cucurbit diseases and fungicide controls. February 6, 2019. New Jersey Agricultural Convention and Trade Show. Atlantic City, NJ. 14. Managing cucurbit mildews. August 20, 2019. Biocontrol Trial and IPM Field Meeting. Fort Plain, NY. 15. WMREC Horticultural twilight meeting and tour, pumpkin disease update. August 15, 2019. Western Maryland Research and Education Center, Keedysville, MD. 16. Late summer horticultural crops twilight meeting, Queenstown, MD 21658. 17. Early detection and control of downy mildew on cucurbits. February, 2019. Southern Maryland Vegetable and Fruit Meeting. Leonardtown, MD. 18. Downy mildew on cucurbits. January, 2019. Central Maryland Vegetable Growers Meeting. Upperco, MD. 19. Proper selection of fungicides and resistant varieties are vital to managing cucurbit downy mildew in cucumbers. January, 2019. Delaware Agriculture Week. Harrington, DE. 20. Cucurbit downy mildew updates and an alternative fungicide spray programs. January, 2019. Delaware Agriculture Week. Harrington, DE. 21. Growing fall cucumbers; Efficacy and economics of downy mildew resistant varieties. January, 2019. New England Vegetable and Berry Growers' Association winter Meeting. 100 growers. Hadley, MA. 22. Managing cucurbit downy mildew using resistant varieties. August, 2019. UMass Crop and Animal Research Farm Research Tour and Twilight Meeting. 45 growers. South Deerfield, MA. 23. Downy mildew on cucurbits - Update. August, 2019. Rutgers Agriculture Research and Education Center Twilight Meeting. Vineland, NJ.s. Results from experiments conducted in 2018 were published in Plant Disease Management Reports: 1. McGrath, M. T. and Sexton, Z. F. 2019. Evaluation of fungicides to reduce chlorothalonil use for powdery mildew on squash, 2018. Plant Disease Management Reports 13:V122. 2. McGrath, M. T. and Sexton, Z. F. 2019. Fungicide sensitivity of cucurbit downy mildew pathogen population on Long Island, NY, determined using a seedling bioassay, 2018. Plant Disease Management Reports 13:V084. 3. McGrath, M. T., Sexton, Z. F., and Nadel, S. 2019. Fungicide sensitivity of cucurbit powdery mildew pathogen populations on Long Island, NY, determined using a seedling bioassay, 2018. Plant Disease Management Reports 13:V161. 4. Everts, K.L., Walter T.L., Jones, J.G., and Johnson G.C. 2019. Evaluation of Fungicide Programs for Management of Downy Mildew of Processing Cucumber- Trial 3, 2018. Plant Disease Management Reports. Online publication. 13:V129. 5. Everts, K.L., Walter T.L., Jones, J.G., and Johnson G.C. 2019. Evaluation of Fungicide Programs for Management of Downy Mildew of Processing Cucumber- Trial 2, 2018. Plant Disease Management Reports. Online publication. 13:V128 6. Everts, K.L., and Walter, T.L. 2019. Evaluation of Elumin Fungicide for Management of Downy Mildew of Processing Cucumber. 2018. Plant Disease Management Reports. 13:V127 What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
We completed our research objectives, analyzed data, and compiled research reports. In addition we conducted outreach and began our program evaluation. Progress at each of our locations is discussed here beginning with the development and evaluation of integrated disease management programs for individual cucurbit species that reduce reliance on chlorothalonil. During fall 2018, we analyzed the data collected from field trials in the summer. Pennsylvania: Similar to the 2016 and 2017 trials with pumpkin, the conventional rotational program replacing chlorothalonil with Microthiol Disperss and Tritek as the tank-mix partner for resistance management was as effective as chlorothalonil based on end of the season lower leaf surface area under the disease progress curve values for both the butternut and delicata squash crops. Also, in all cases, inclusion of these products as well as chlorothalonil as tank-mix partners in the program (Luna Experience, Vivando and Torino) was more effective than season-long applications of the products individually. Season-long applications of Bravo WeatherStik, Microthiol Disperss or Tritek were no more effective than the untreated control by the end of the season. New York: This trial complemented the identical trial conducted in PA.Disease development was slower in butternut (cv. Atlas) than Bush Delicata. Fungicide treatments performed similarly in both. Bravo Ultrex and the two chlorothalonil alternative fungicides, Microthiol Disperss and Tritek, when tested alone were more effective at controlling powdery mildew on upper than lower leaf surfaces as expected due to their contact activity. Microthiol Disperss was as effective as Bravo Ultrex at all assessments. At the last severity assessment, which was 10 days after the last treatment application, Tritek was less effective at managing powdery mildew on upper leaf surfaces than Microthiol Disperss and Bravo Ultrex on Atlas and less effective than Microthiol Disperss on Bush Delicata. Microthiol Disperss and Tritek were effective for powdery mildew on lower leaf surfaces of Bush Delicata while Bravo Ultrex was not based on AUDPC values. Effective control was obtained with the grower standard fungicide program, which was Bravo Ultrex applied with a rotation of Luna Experience, Vivando, and Quintec. Powdery mildew was often numerically, albeit never significantly, less severe when Bravo Ultrex in this program was replaced with less commonly used Tritek and Microthiol Disperss. New Jersey: Two zucchini cultivars, "Senator' and Reward F1 were grown, which were susceptible and resistant to powdery mildew, respectively. Powdery mildew severity was low in 2018. The non-fungicide treated resistant cultivar had significantly less powdery mildew than the non-fungicide treated susceptible cultivar. However, cultivar resistance did not result in lower powdery mildew under most fungicide programs. The best control was achieved when specific high-risk modes of action fungicides were applied before disease was observed and continued season-long. Maryland: Gummy stem blight severity in the reduced chlorothalonil treatment and commercial standard treatment were similar on all three cucurbits. The commercial standard controlled anthracnose in watermelon significantly better, with an average disease rating of 3.3%, compared to the higher disease severity of 17.1% in the reduced chlorothalonil treatment. Powdery mildew severity between the reduced chlorothalonil and commercial standards was statistically similar, with less than 1% disease severity between the two treatments in each of the three crops. Results suggest that overall, chlorothalonil can be replaced in the short term with biopesticides with little effect on cucurbit disease management, except when multiple diseases are present. Cucurbit downy mildew bioassays: Seedling bioassays were conducted to examine occurrence of reduced efficacy of fungicides likely due to fungicide resistance in cucurbit downy mildew populations. Pennsylvania: One cucumber bioassay (cv. Silver Slicer) was conducted in September 2018 on a commercial farm in Blair Co. (south central), PA following the protocol Keinath (2016). The bioassay was set out in sporulating cucumber field for 48 hr. A total of eight fungicides were evaluated at field rate. Revus was not included since no product was on hand and unfortunately, Previcur Flex was applied at the wrong rate and therefore excluded from the dataset. In summary, downy mildew developed on the untreated bioassay plants as well as those treated with Quadris (FRAC 11), Forum (40) and Curzate (27) although there was variability between the four replicates. In comparison, Orondis (U15), Ranman (21), Omega (29) and surprisingly Presidio (43) were effective with few to no symptoms developing on the bioassay plants. New York: Quadris, Revus, and Presidio were ineffective at both rates likely due to fungicide resistance, which has been previously reported. None of these fungicides had been applied in the field experiment this season therefore selection for resistance occurred elsewhere. The other eight fungicides tested were very effective at both full and half label rates. Five of these (Previcur Flex, Orondis, Ranman, Zampro, and Bravo) had been applied as components of fungicide programs tested in the field experiment where the seedling bioassay was conducted. Maryland: The bioassays were exposed to natural P. cubensis populations in infected fields at the UMD LESREC in Salisbury. The fungicides cyazofamid (Ranman), zoxamide + chlorothalonil (Zing!), chlorothalonil (Bravo), and oxathiapiprolin (Orondis), and fluopicolide (Presidio) all provided excellent control (96-100% disease reduction compared to the untreated control) at both full and half-label rates (Table 4). Penthiopyrad (Fontelis), triflumizole (Procure), and azoxystrobin (Quadris) were not statistically different from the untreated control at the full-label rate, suggesting limited utility of these chemicals in CDM management. Sentinel Plots: In 2019 sentinel plots were established formonitoring occurrence of downy mildew in different cucurbit crop types to contribute information on occurrence to the ipmPIPE cucurbit downy mildew forecasting program. Two cucurbit downy mildew sentinel plots were established at the Russell E. Larson Agricultural Research Center at Rock Springs in Centre Co. and the Southeast Agricultural Research and Extension Center in Lancaster Co. PA. Downy mildew was first detected in Lancaster Co. on processing pumpkin on 1 Aug, jack-o-lantern pumpkin on 6 Aug and cucumber on 29 Aug. In Centre Co. it was detected on cucumber on 18 Aug. A total of 14 reports of downy mildew were made across PA during the 2019 growing season. On Long Island, NY,There were 2 sentinel plot plantings (mid-June and mid-July).Symptoms were found on cucumber on 19 Aug in a research planting near sentinel plots, 27 Aug on cantaloupe in the sentinel plots, and 27 Aug on butternut squash in a research planting near sentinel plots. Sentinel plots were established in MD at the Central Maryland Research and Education Center, Upper Marlboro and LESREC, Salisbury. The first observed downy mildew in MD was on 24 June in a commercial processing cucumber field. In MA one sentinel plot was planted on 28 May and downy mildew was first observed in the plot on 20 August, 2019. However, it was detected earlier on 3, July in MA on Cape Cod (Barnstable Co.) by Extension agents. In NJ, one sentinel plot was planted in Pittstown.Downy mildew was first observed there on 30 July on watermelon and winter squash.However, downy mildew had been previously observed in a commercial cucumber field in southern New Jersey on 4 July.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Jones, J.G. and Everts, K.L. Using Cucurbit Downy Mildew Assays to Monitor Fungicide Resistance. 2018 Soilborne
Oomycete Conference. Islamorada, FL
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
McGrath, M. T., Gugino, B. K., Scheufele, S. B. 2019. Evaluation of fungicides and resistant cultivars to reduce use of
chlorothalonil for powdery mildew in pumpkin and winter squash. Phytophthology 109:S2.97.
https://doi.org/10.1094/PHYTO-109-10-S2.97.
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
McGrath, M. T., Scheufele, S. B., and Gugino, B. K., 2019. Evaluation of fungicides and resistant cultivars to reduce use
of chlorothalonil for powdery mildew in pumpkin and winter squash. Phytopathology 108: (accepted).
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Jones, J.G., Everts, K.L., Korir, R.C., and Walter, T.L., 2019. The Effects of Reducing Chlorothalonil Use in Fungicide
Spray Programs for Melon Diseases. American Phytopathological Society Annual Meeting, Cleveland, OH. Aug 3-7.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Jones, J.G., Everts, K.L., and Johnson, G. 2019 Evaluation of fungicide programs and resistant varieties for management
of downy mildew in processing cucumber. Potomac Division APS, Rehoboth Beach, DE (Abstr.) Phytopathology
109:S1.14. https://doi.org/10.1094/PHYTO-109-9- S1.14
- Type:
Journal Articles
Status:
Awaiting Publication
Year Published:
2020
Citation:
Jake G. Jones, Robert C. Korir, Taylor L. Walter, and Kathryne L. Everts. 2020. Reducing Chlorothalonil Use in Fungicide Spray Programs for Powdery Mildew, Anthracnose, and Gummy Stem Blight in Melons. Plant Dis. 104:XX
- Type:
Journal Articles
Status:
Submitted
Year Published:
2021
Citation:
Jake G. Jones, Kathryne L. Everts, Margaret T. McGrath, and Beth K. Gugino. 20XX. Efficacy of Preventative Fungicides on Pseudoperonospora cubensis in the MidAtlantic and Northeast over Multiple Years. Plant Health Progress
|
Progress 09/01/18 to 08/31/19
Outputs
Target Audience:Our stakeholders are cucurbit growers, pest management advisers, consultants, extension educators, agricultural industry personnel, and beekeepers throughout the Northeast and mid-Atlantic regions and other locations with similar production systems. Within our research group, we all have partial extension appointments and regularly teach these stakeholder groups. Our project has been successfully initiated and as it progresses, it will improve in-season disease management decisions. It will enable growers to effectively manage pests while reducing pollinator exposure to key fungicides and our results will be incorporated into existing IPM programs that include the use of crop rotation, host resistance (when available), scouting, and disease and forecasting tools. Changes/Problems:There were two changes to our original project during this reporting period. During the final year of the multi-state field trials (2018) to evaluate efficacy of integrated management alternatives to the use of chlorothalonil on cucurbit crop diseases, the seed supplied for the butternut squash trials conducted in PA, NY and MA was not what was originally requested but rather a powdery mildew susceptible delicata-type squash rather than a resistant butternut squash. The trial was evaluated as planted, and resulted in our inability to evaluate the contribution of host resistance to the overall integrated program in these trials. A second change to the project is that although we planned to finish in fall 2019, we are continuing to complete the evaluation of the impact of outputs, and learning outcomes. To complete this work we will obtain additional survey information. The evaluation efforts will be led by Dr. Archibald and a Graduate Research Assistant. What opportunities for training and professional development has the project provided?One-on-one discussions were held with various student interns regarding the purpose of the established trial to evaluate the use of alternative fungicide programs that reduce the reliance on chlorothalonil for the management of powdery mildew on pumpkin. Research station visitors learned about the approved goals and research outcomes. General concepts of the project and the use of bioassays to monitor and document fungicide resistance was included in course lectures for the Plant Science capstone Integrated Pest Management course at Pennsylvania State University. One graduate student was supported at UMD through this grant. How have the results been disseminated to communities of interest?The research results have been disseminated at several regional vegetable grower meetings/ conferences including the Mid-Atlantic Fruit and Vegetable Convention in Hershey, PA, University of Delaware Ag Week, and the New Jersey Agricultural Convention and Trade Show, see below. Extension news articles across the region also presented information on the project. In New York, information about CDM occurrence in the eastern US and fungicide recommendations were provided to Long Island growers in the weekly Long Island Fruit & Vegetable Update during the 2019 growing season. In Maryland and Delaware, updates on CDM occurrence were published in the University of Delaware Weekly Crop Update, and the University of Maryland Extension Fruit and Vegetable News. A research update article (Jones, J.G., and Everts, K.L., 2018. Early Detection and Control of Downy Mildew on Cucurbits) summarized the project findings in University of Maryland Extension, Vegetable and Fruit Headline News, Special Research Edition. Locally, results were also disseminated throughout the season through one-on-one meetings and conversations with growers, at summer twilight meetings and through regular extension activities (see extension presentation list below). Information about fungicides and fungicide resistance is also frequently included in disease alerts and extension newsletter articles with a link to the updated cucurbit powdery and downy mildew fungicide resistance management guidelines (PHP 2018 19:34-36). Hardcopies of the recommendations table were distributed at educational kiosks at eight produce auctions across Pennsylvania to provide resources to the primarily Anabaptist community that does not access information electronically. Extension presentations were given across our multi-state area that included information about project results and recommendations based on these results. Vegetable disease update: What have we been seeing in 2019? July 31, 2019. Kutztown Produce Auction Vegetable Meeting. Fleetwood, PA. Vegetable disease update. March 7, 2019. Small Fruit and Vegetable Meeting - Montgomery County. Worcester, PA. Vine crop disease management in wet year. January 31, 2019. Mid-Atlantic Fruit and Vegetable Convention. Hershey Lodge & Convention Center, Hershey, PA. Vine crop disease management in wet years. January 25, 2019. Juniata County Plain-sect Auction Growers Meeting. Thompsontown, PA. Vegetable disease management: Surviving a wet year. January 24, 2019. Northeast Vegetable Growers Meeting. Newton Ransom Fire Company, Clarks Summit, PA. Vegetable pathology research projects. September 6, 2018. Plant Science Day. Riverhead, NY. Thirty years of research helping farmers manage diseases of cucurbits. September 26, 2018. Watermelon and Melon Training. Zhengzhou, China. What's new about downy mildews and their management in basil and other crops. January 1, 2019. 2019 Long Island Agricultural Forum. Sustainable Session. Speonk, NY. Key facts to know about plant diseases occurring in the region and their management. January 10, 2019. 2019 Long Island Agricultural Forum. Beginning Farmer Session. Speonk, NY. Successfully managing diseases in 2019 based on what was learned in 2018. January 10, 2019. 2019 Long Island Agricultural Forum. Vegetable Session. Speonk, NY. Managing mildews and phytophthora blight successfully in 2019. January 15, 2019. 2019 Empire State Producers Expo. Vine Crops Session. Syracuse, NY. Managing powdery mildew on cucurbits and tunnel tomatoes. January 21, 2019. Vermont Vegetable and Berry Growers Association Annual Meeting. Fairlee, VT. Cucurbit diseases and fungicide controls. February 6, 2019. New Jersey Agricultural Convention and Trade Show. Atlantic City, NJ. Managing cucurbit mildews. August 20, 2019. Biocontrol Trial and IPM Field Meeting. Fort Plain, NY. WMREC Horticultural twilight meeting and tour, pumpkin disease update. August 15, 2019. Western Maryland Research and Education Center, Keedysville, MD. Late summer horticultural crops twilight meeting, Queenstown, MD 21658. Early detection and control of downy mildew on cucurbits. February, 2019. Southern Maryland Vegetable and Fruit Meeting. Leonardtown, MD. Downy mildew on cucurbits. January, 2019. Central Maryland Vegetable Growers Meeting. Upperco, MD. Proper selection of fungicides and resistant varieties are vital to managing cucurbit downy mildew in cucumbers. January, 2019. Delaware Agriculture Week. Harrington, DE. Cucurbit downy mildew updates and an alternative fungicide spray programs. January, 2019. Delaware Agriculture Week. Harrington, DE. Growing fall cucumbers; Efficacy and economics of downy mildew resistant varieties. January, 2019. New England Vegetable and Berry Growers' Association winter Meeting. 100 growers. Hadley, MA. Managing cucurbit downy mildew using resistant varieties. August, 2019. UMass Crop and Animal Research Farm Research Tour and Twilight Meeting. 45 growers. South Deerfield, MA. Downy mildew on cucurbits - Update. August, 2019. Rutgers Agriculture Research and Education Center Twilight Meeting. Vineland, NJ.s. Results from experiments conducted in 2018 were published in Plant Disease Management Reports: McGrath, M. T. and Sexton, Z. F. 2019. Evaluation of fungicides to reduce chlorothalonil use for powdery mildew on squash, 2018. Plant Disease Management Reports 13:V122. McGrath, M. T. and Sexton, Z. F. 2019. Fungicide sensitivity of cucurbit downy mildew pathogen population on Long Island, NY, determined using a seedling bioassay, 2018. Plant Disease Management Reports 13:V084. McGrath, M. T., Sexton, Z. F., and Nadel, S. 2019. Fungicide sensitivity of cucurbit powdery mildew pathogen populations on Long Island, NY, determined using a seedling bioassay, 2018. Plant Disease Management Reports 13:V161. Everts, K.L., Walter T.L., Jones, J.G., and Johnson G.C. 2019. Evaluation of Fungicide Programs for Management of Downy Mildew of Processing Cucumber- Trial 3, 2018. Plant Disease Management Reports. Online publication. 13:V129. Everts, K.L., Walter T.L., Jones, J.G., and Johnson G.C. 2019. Evaluation of Fungicide Programs for Management of Downy Mildew of Processing Cucumber- Trial 2, 2018. Plant Disease Management Reports. Online publication. 13:V128 Everts, K.L., and Walter, T.L. 2019. Evaluation of Elumin Fungicide for Management of Downy Mildew of Processing Cucumber. 2018. Plant Disease Management Reports. 13:V127 What do you plan to do during the next reporting period to accomplish the goals?This year was projected to be our final year of the project. However, our evaluation of the impact of outputsand learning outcomeswill continue to be conducted in 2020. We are waiting for confirmation of a no cost extension. To complete this work we will obtain information needed to complete the evaluation, for example, additional surveys. The evaluation efforts will be led by Dr. Archibald and a Graduate Research Assistant. In addition, we are completing the summary of the field research and fungicide bioassays including preparation of manuscripts, fact sheets and reports.
Impacts
What was accomplished under these goals?
We completed our research objectives, analyzed data, and compiled research reports. In addition we conducted outreach and began our program evaluation. Progress at each of our locations is discussed here beginning with the development and evaluation of integrated disease management programs for individual cucurbit species that reduce reliance on chlorothalonil.During fall 2018, we analyzed the data collected from field trials in the summer. Pennsylvania: Similar to the 2016 and 2017 trials with pumpkin, the conventional rotational program replacing chlorothalonil with Microthiol Disperss and Tritek as the tank-mix partner for resistance management was as effective as chlorothalonil based on end of the season lower leaf surface area under the disease progress curve values for both the butternut and delicata squash crops. Also, in all cases, inclusion of these products as well as chlorothalonil as tank-mix partners in the program (Luna Experience, Vivando and Torino) was more effective than season-long applications of the products individually. Season-long applications of Bravo WeatherStik, Microthiol Disperss or Tritek were no more effective than the untreated control by the end of the season. New York: This trial complemented the identical trial conducted in PA.Disease development was slower in butternut (cv. Atlas) than Bush Delicata. Fungicide treatments performed similarly in both. Bravo Ultrex and the two chlorothalonil alternative fungicides, Microthiol Disperss and Tritek, when tested alone were more effective at controlling powdery mildew on upper than lower leaf surfaces as expected due to their contact activity. Microthiol Disperss was as effective as Bravo Ultrex at all assessments. At the last severity assessment, which was 10 days after the last treatment application, Tritek was less effective at managing powdery mildew on upper leaf surfaces than Microthiol Disperss and Bravo Ultrex on Atlas and less effective than Microthiol Disperss on Bush Delicata. Microthiol Disperss and Tritek were effective for powdery mildew on lower leaf surfaces of Bush Delicata while Bravo Ultrex was not based on AUDPC values. Effective control was obtained with the grower standard fungicide program, which was Bravo Ultrex applied with a rotation of Luna Experience, Vivando, and Quintec. Powdery mildew was often numerically, albeit never significantly, less severe when Bravo Ultrex in this program was replaced with less commonly used Tritek and Microthiol Disperss. New Jersey: Two zucchini cultivars, "Senator' and Reward F1 were grown, which were susceptible and resistant to powdery mildew, respectively. Powdery mildew severity was low in 2018. The non-fungicide treated resistant cultivar had significantly less powdery mildew than the non-fungicide treated susceptible cultivar. However, cultivar resistance did not result in lower powdery mildew under most fungicide programs. The best control was achieved when specific high-risk modes of action fungicides were applied before disease was observed and continued season-long. Maryland: Gummy stem blight severity in the reduced chlorothalonil treatment and commercial standard treatment were similar on all three cucurbits. The commercial standard controlled anthracnose in watermelon significantly better, with an average disease rating of 3.3%, compared to the higher disease severity of 17.1% in the reduced chlorothalonil treatment. Powdery mildew severity between the reduced chlorothalonil and commercial standards was statistically similar, with less than 1% disease severity between the two treatments in each of the three crops. Results suggest that overall, chlorothalonil can be replaced in the short term with biopesticides with little effect on cucurbit disease management, except when multiple diseases are present. Cucurbit downy mildew bioassays: Seedling bioassays were conducted to examine occurrence of reduced efficacy of fungicides likely due to fungicide resistance in cucurbit downy mildew populations. Pennsylvania: One cucumber bioassay (cv. Silver Slicer) was conducted in September 2018 on a commercial farm in Blair Co. (south central), PA following the protocol Keinath (2016). The bioassay was set out in sporulating cucumber field for 48 hr. A total of eight fungicides were evaluated at field rate. Revus was not included since no product was on hand and unfortunately, Previcur Flex was applied at the wrong rate and therefore excluded from the dataset. In summary, downy mildew developed on the untreated bioassay plants as well as those treated with Quadris (FRAC 11), Forum (40) and Curzate (27) although there was variability between the four replicates. In comparison, Orondis (U15), Ranman (21), Omega (29) and surprisingly Presidio (43) were effective with few to no symptoms developing on the bioassay plants. New York: Quadris, Revus, and Presidio were ineffective at both rates likely due to fungicide resistance, which has been previously reported. None of these fungicides had been applied in the field experiment this season therefore selection for resistance occurred elsewhere. The other eight fungicides tested were very effective at both full and half label rates. Five of these (Previcur Flex, Orondis, Ranman, Zampro, and Bravo) had been applied as components of fungicide programs tested in the field experiment where the seedling bioassay was conducted. Maryland: The bioassays were exposed to natural P. cubensis populations in infected fields at the UMD LESREC in Salisbury. The fungicides cyazofamid (Ranman), zoxamide + chlorothalonil (Zing!), chlorothalonil (Bravo), and oxathiapiprolin (Orondis), and fluopicolide (Presidio) all provided excellent control (96-100% disease reduction compared to the untreated control) at both full and half-label rates (Table 4). Penthiopyrad (Fontelis), triflumizole (Procure), and azoxystrobin (Quadris) were not statistically different from the untreated control at the full-label rate, suggesting limited utility of these chemicals in CDM management. Sentinel Plots: In 2019 sentinel plots were established formonitoring occurrence of downy mildew in different cucurbit crop types to contribute information on occurrence to the ipmPIPE cucurbit downy mildew forecasting program. Two cucurbit downy mildew sentinel plots were established at the Russell E. Larson Agricultural Research Center at Rock Springs in Centre Co. and the Southeast Agricultural Research and Extension Center in Lancaster Co. PA. Downy mildew was first detected in Lancaster Co. on processing pumpkin on 1 Aug, jack-o-lantern pumpkin on 6 Aug and cucumber on 29 Aug. In Centre Co. it was detected on cucumber on 18 Aug. A total of 14 reports of downy mildew were made across PA during the 2019 growing season. On Long Island, NY,There were 2 sentinel plot plantings (mid-June and mid-July).Symptoms were found on cucumber on 19 Aug in a research planting near sentinel plots, 27 Aug on cantaloupe in the sentinel plots, and 27 Aug on butternut squash in a research planting near sentinel plots. Sentinel plots were established in MD at the Central Maryland Research and Education Center, Upper Marlboro and LESREC, Salisbury. The first observed downy mildew in MD was on 24 June in a commercial processing cucumber field. In MA one sentinel plot was planted on 28 May and downy mildew was first observed in the plot on 20 August, 2019. However, it was detected earlier on 3, July in MA on Cape Cod (Barnstable Co.) by Extension agents. In NJ, one sentinel plot was planted in Pittstown.Downy mildew was first observed there on 30 July on watermelon and winter squash.However, downy mildew had been previously observed in a commercial cucumber field in southern New Jersey on 4 July.
Publications
- Type:
Journal Articles
Status:
Accepted
Year Published:
2019
Citation:
McGrath, M. T., Scheufele, S. B., and Gugino, B. K., 2019. Evaluation of fungicides and resistant cultivars to reduce use of chlorothalonil for powdery mildew in pumpkin and winter squash. Phytopathology 108: (accepted).
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Jones, J.G., Everts, K.L., Korir, R.C., and Walter, T.L., 2019. The Effects of Reducing Chlorothalonil Use in Fungicide Spray Programs for Melon Diseases. American Phytopathological Society Annual Meeting, Cleveland, OH. Aug 3-7.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Jones, J.G., Everts, K.L., and Johnson, G. 2019 Evaluation of fungicide programs and resistant varieties for management of downy mildew in processing cucumber. Potomac Division APS, Rehoboth Beach, DE (Abstr.) Phytopathology 109:S1.14. https://doi.org/10.1094/PHYTO-109-9- S1.14
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Jones, J.G. and Everts, K.L. Using Cucurbit Downy Mildew Assays to Monitor Fungicide Resistance. 2018 Soilborne Oomycete Conference. Islamorada, FL
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
McGrath, M. T., Gugino, B. K., Scheufele, S. B. 2019. Evaluation of fungicides and resistant cultivars to reduce use of chlorothalonil for powdery mildew in pumpkin and winter squash. Phytophthology 109:S2.97. https://doi.org/10.1094/PHYTO-109-10-S2.97.
|
Progress 09/01/17 to 08/31/18
Outputs
Target Audience:Our stakeholders are cucurbit growers, pest management advisors, consultants, extension educators, agricultural industry personnel, and beekeepers throughout the Northeast and mid-Atlantic regions and other locations with similar production systems. Within our research group, we all have partial extension appointments and regularly teach these stakeholder groups. Our project has been successfully initiated and as it progresses, it will improve in-season disease management decisions. It will enable growers to effectively manage pests while reducing pollinator exposure to key fungicides and our results will be incorporated into existing IPM programs that include the use of crop rotation, host resistance (when available), scouting, and disease and forecasting tools. Changes/Problems:We made some improvements to our project over the past year. For example, se have changed our measure of sub-lethal fungicide effects test disease from Nosema to deformed wing virus (DWV) infection due to consistency issues related to Nosema infection rates. We have also added several other tests to look for sublethal effects in hopes of developing field standardized testing techniques. Additionally some problems were encountered, such as that the measurement of fungicide concentration within the doped pollen substitute was not what was expected, but the difference was attributed to half-life degradation from the time of mixing to the time of testing. Field trials of fungicide alternatives and bioassays also encountered weather challenges with excess rain in both the fall of 2017 in MD and VA. Some bioassays were not successful in NY due to too short an exposure period, inadequate inoculum, environmental conditions in the green hose being unfavorable (too hot) or plants being in poor condition (too old). Modifications to procedures, such as using a canopy to minimize sunscald and pinching the growing point to minimize stem elongation are being employed to improve results. The seed supplied for the butternut squash trials conducted in PA, NY and MA was not what was originally requested but rather a powdery mildew susceptible delicate-type squash rather than a resistant butternut squash. However, the trial is continuing to be evaluated as planted. What opportunities for training and professional development has the project provided?Opportunities for training and professional development occurred across locations. Our PI and co-PI personnel have benefited by working with our large collaborator group in many states. For example, UMass personnel found the group helpful in learning how to setup larger field experiments and will learn how to prepare results for publication in an academic journal this winter. Additional opportunities occurred for four undergraduate students and one graduate student, who received training on method development at the USDA Beltsville bee lab. At PSU, one-on-one discussions were held with various student interns regarding the purpose of the established trial to evaluate the use of alternative fungicide programs that reduce the reliance on chlorothalonil for the management of powdery mildew on pumpkin. General concepts of the project and the use of bioassays to monitor and document fungicide resistance was included in course lectures for the PSU Plant Science capstone Integrated Pest Management course. How have the results been disseminated to communities of interest?Reports of downy mildew occurrence were submitted by our research group from Long Island, PA, MA, MD, DE, VA and NJ to the ipmPIPE cucurbit downy mildew forecasting program website. Information about occurrence in the eastern US and fungicide recommendations were provided to growers throughout New England and the mid-Atlantic in news articles. For example, Dr. McGrath wrote several news articles for the weekly Long Island Fruit & Vegetable Update during the 2018 growing season. New England growers received updates in news articles and pest alerts written for the weekly Extension newsletter, Vegetable Notes, with a readership >2,500. In PA, information about fungicides and fungicide resistance is also frequently included in disease alerts and extension newsletter articles with a link to the updated cucurbit powdery and downy mildew fungicide resistance management guidelines (PHP 2018 19:34-36). Hardcopies of the recommendations table were distributed at educational kiosks at eight produce auctions across PA to provide resources to the primarily Anabaptist community that does not access information electronically. In MD and DE outbreaks of downy mildew along with recommendations were reported in the UD Weekly Crop Update Newsletter. Throughout the states that participated in this research, NY, PA, MA, MD, DE, VA, and NJ, results were disseminated throughout the season through one-on-one meetings and conversations with growers, at summer twilight meetings and through regular extension activities (see extension presentation list below). Collectively we disseminated our research outcomes in 31 extension meetings. Update on Fungicides for Managing Disease in Pumpkins. December, 12, 2017. New England Vegetable and Fruit Conference. Manchester, NH. (McGrath) Effectively Managing Significant Diseases on Long Island. January 11, 2018. Vegetable Session. 2018 Long Island Agricultural Forum. Speonk, NY. (McGrath) Managing Mildews with Resistant Varieties and Fungicides. January 18. 2018 Empire State Producers Expo. Vine Crops Session. Syracuse, NY. (McGrath) What's New with Major Diseases of Vegetable Crops. February 3, 2018. NH Vegetable & Berry Growers' Association Annual Meeting. Manchester, NH. (McGrath) New Developments in Managing Powdery and Downy Mildews in Cucurbits. February 6, 2018. Vine Crops Session. New Jersey Agricultural Convention and Trade Show. Atlantic City, NJ. (McGrath) Resistance to Fungicides in Vegetable Pathogens: Current Situation and Strategies for Managing. August 16, 2018. 3rd International Congress on Plant Protection in Vegetables. Guadalajara, Mexico. (McGrath) Options for Organic Management of Diseases in Vegetable Crops. August 17, 2018. 3rd International Congress on Plant Protection in Vegetables. Guadalajara, Mexico. (McGrath) Vegetable disease update and field walk. July 17, 2018. Central Susquehanna Vegetable Twilight Meeting. Amos Martin Farm, Middleburg, PA. (Gugino) Pest and disease walk. July 16, 2018. Sugar Valley Vegetable Grower Twilight Meeting. Amos Glick Farm, Loganton, PA. (Gugino) Mildew management in cucurbits. February 1, 2018. Mid-Atlantic Fruit and Vegetable Convention, Hershey Lodge & Convention Center, Hershey, PA. (Gugino) Top vegetable disease problems of 2017. January 25, 2018. Northeast Vegetable Growers Meeting, Newton Ransom Fire Company, Clarks Summit, PA. (Gugino) Vegetable disease update. January 15, 2018. New Holland Vegetable Day, Yoder's Restaurant and Buffet, New Holland, PA. (Gugino) Vegetable disease management. December 20, 2017. Ephrata Agway Vegetable Grower Meeting, Shady Maple Banquet Center, East Earl, PA. (Gugino) Disease management 101: Problems from 2017 and management recommendations. December 14, 2017. Quarryville Produce Growers Meeting. Hoffman Building at Solanco Fairgrounds, Quarryville, PA. (Gugino) Vegetable disease diagnostics and scouting for improved profitability. December 13, 2017. Growing Pennsylvania Organic Conference. Sheraton Harrisburg-Hershey, Harrisburg, PA. (Gugino) Cucurbit downy mildew sentinel plot system and fungicide options. August 16, 2018. (35 attendees), Univ. Massachusetts Twilight Meeting. (Scheufele) Update on Diseases of Vegetable Crops. Feb. 13, 2018. Eastern Shore Vegetable and Fruit Meeting, Cambridge, MD. (Everts) Vegetable Diseases and Fungicide Update. Feb. 8, 2018. Southern Maryland Vegetable and Fruit Meeting, Gambrills, MD. (Everts) Downy Mildew Control and Fungicide Resistance Jan. 9, 2018. Delaware Agriculture Week - Fresh Market Session. Harrington, DE. (Jones). Organic Melon production - Cucurbit and Hop Downy Mildew: Sister Species. July 25, 2018. Horticultural Crops Twilight Meeting. Wye Mills, DE. (Jones) Downy Mildew Resistant Cucumber Trials. Jan. 10, 2018. Processing Vegetables Session. Harrington, DE. (Everts) Early Detection and Control of Downy Mildew and Control of Downy Mildew on Cucurbits. August 8, 2018. Crops Twilight Tour CMREC Upper Marlboro Farm, MD (Jones) Cucurbit downy mildew. June 27, 2018. Farmers' Field Day at UMD Lower Eastern Shore Research and Education Center, Salisbury, MD. (Jones) Vegetable Production and IPM Walking Tour in St. Mary's County, MD. August 10. 2018. (Everts) Northern Neck Vegetable Growers Meeting, Warsaw, VA, Dec. 2017, 44 participants. (Rideout) Vegetable Session, Eastern Shore Ag Conference and Trade Show, Melfa, VA, Jan. 2018, 65 participants. (Rideout) SE Virginia Vegetable Growers Meeting, Chesapeake, VA, Feb. 2018, 49 participants. (Rideout) Tidewater Area Vegetable Growers, Suffolk, VA, Feb. 2018, 33 particpants. (Rideout) Richmond Area Vegetable Growers Meeting, Richmond, VA, Feb. 2018, 51 participants. (Rideout) Shenandoah Valley Vegetable Growers Meeting, Harrisonburg, VA, Mar. 2018, 62 participants. (Rideout) New Jersey Agricultural Convention and Trade Show in Atlantic City on Feb. 6-8, 2018. (Wyenandt) Results from experiments conducted in 2017 were published: McGrath, M. T. and Sexton, Z. F. 2018. Evaluation of management programs without chlorothalonil for powdery mildew in pumpkin, 2017. Plant Disease Management Reports 12:V073. McGrath, M. T. and Sexton, Z. F. 2018. Fungicide sensitivity of cucurbit downy mildew pathogen population on Long Island, NY, determined with seedling bioassay, 2017. Plant Disease Management Reports 12:V152. McGrath, M. T. and Sexton, Z. F. 2018. Fungicide sensitivity of cucurbit powdery mildew pathogen population on Long Island, NY, determined with seedling bioassay, 2017. Plant Disease Management Reports 12:V153. What do you plan to do during the next reporting period to accomplish the goals?Several additional experiments are either underway or in the planning stages. Currently we are running trials to determine any levels of increased mortality on caged populations of honey bees fed field relevant fungicide doped pollen substitute. Additionally, we are using a technique called Proboscis Extension Reflex (PER) to assess any detrimental effects the stated fungicides may have on honey bee learning ability. Also in the planning stages are experiments to verify the results of the exploratory RNA sequencing, determine the extent of mitochondrial stress by comparison of metabolic rates across treatment groups, and measure any potential sublethal effects of these fungicides in the presence of DWV, a common honey bee virus. We will also complete ongoing field research activities on fungicide alternatives during the 2018 growing season, analyze data and write reports, and present findings at grower meetings. Our fourth year will focus on the development of additional outreach tools from our research such as fact sheets. We will present final results at grower meetings and develop our findings into peer-reviewed journal articles to reach a wider audience. Final year surveys will be conducted to evaluate the learning outcomes of growers across the region.
Impacts
What was accomplished under these goals?
During the third year of this research project we made progress on all of our goals. For objective 1, our team broadened the scope to look at sub lethal effects of fungicide exposure on honey bees in a more robust way, as measured in different assays. We decided not to use Nosema, which is highly variable, as a surrogate for sub lethal exposures. We replaced that test with more robust tests of sub lethal effects, which are ongoing, include evaluating the effect of exposure to fungicides on bee learning, longevity, and gross anatomical characteristics. We are developing a model system (with USDA) on the use of clonal deformed wing virus (DWV) as a pathogenic challenge. This will replace the use of the highly variable Nosema sp. as the model pathogen. We have successfully quantified the fungicidal exposure from pollen that bees collect from freshly sprayed flowers. Using this information, we fed dosed bee feed (protein) to bees to produce exploratory data on possible differentially expressed genes that result from fungicide consumption. Using the field detected levels of chlorothalonil and Pristine active ingredients, we fed a formula-doped pollen substitute to newly emerged bees and compared their respective RNA levels to a control group free of fungicides. Initial analysis indicates that field relevant levels may negatively influence ATP production and mitochondrial health. Because this analysis was too expensive to do with proper repetition, we are now evaluating target genes in upcoming and ongoing cage trials. Our research team also made progress in addressing key barriers to reducing chlorothalonil in fungicide programs. The research conducted during the 2017 growing season was completed and analyzed following our last annual report, and research activities for the 2018 season were started.Highlights of our research results are described here. On Long Island, and in PA, and MA, an experiment is being conducted to evaluate fungicide programs on disease development and yield in winter squash. Host resistance to powdery mildew (resistant cv. Honeynut and susceptible cv. Atlas) and alternative multi-site mode of action fungicides are being evaluated. The mineral oil-based fungicide, Tritek, and the sulfur-based fungicide, Microthiol Disperss, were selected to compare to the chlorothalonil-based fungicide, Bravo Ultrex. Experiments are ongoing, however briefly powdery mildew was first observed in PA at the end of July. The results of the parallel trial completed on pumpkin in 2017 are that on Long Island powdery mildew severity on the resistant cv. Bayhorse Gold did not differ significantly at any assessment time from the horticulturally-comparable susceptible cv., Gold Challenger. Microthiol Disperss was as effective as Bravo Ultrex across all measurements of severity as well as defoliation and fruit handle quality, which are measures of the impact of powdery mildew. Tritek effectively managed powdery mildew, but not quite as well on upper leaf surfaces as Bravo Ultrex or Microthiol Disperss; however, it was the most effective for powdery mildew on lower leaf surfaces while Bravo Ultrex was ineffective. Surprisingly, Tritek was least effective of the three while Microthiol Disperss was best for preserving handle quality. The fungicide programs tested consisted of rotation of Luna Experience, Vivando, and Torino. These single-site mode of action fungicides were tank mixed with a contact fungicide. In conclusion, the two Bravo alternatives tested were found to be more effective fungicides for managing powdery mildew than Bravo. The field experiment in MD in 2018 is ongoing, and is comparing fungicide alternatives to chlorothalonil in a melon cropping system on multiple diseases. Oso (polyoxin D zinc salt) and Regalia (extract ofReynoutria sachalinensis) are being examined as stand-alone treatments and as replacements of Bravo Weatherstik in a tank-mix with a rotation of targeted fungicides. There are three melon cultivars, cv. Crunchy Red watermelon, cv. Snow Leopard honeydew melon, and powdery resistant muskmelon cv. Athena. Natural inoculum was relied upon and the primary diseases were gummy stem blight and powdery mildew. Weekly fungicide sprays were started when the vines touched within the rows and weekly disease rating started on July 20th. Briefly, results from 2017 showed the tank-mixes of targeted fungicides with chlorothalonil and the alternatives to chlorothalonil to be statistically similar. This suggests that alternatives to chlorothalonil are available. The targeted fungicides used were: Inspire Super (difenconazole and cyprodonil), Folicur (tebucanazole), Fontelis (penthiopyrad), and Torino (cyflufenamid). At Virginia Tech's Eastern Shore Agricultural Research and Extension Center, field research examining fungicide programs to manage cucumber diseases was conducted in the fall of 2017 and analyzed. The experiment is currently being repeated in 2018. The primary disease in these trials was downy mildew,Pseudoperonospora cubensis. The field research trials examined four different fungicide spray programs on both fresh market and processing cucumber cultivars that varied in their level of host resistance (Dasher II, SV4719CS, SMR58, and Supremo). The fungicide programs (four applications in 2017) were sprayed on a 10-day intervals. In 2017, cultivars that have downy mildew tolerance offered very minimal disease protection, and the program without chlorothalonil was as effective at managing downy mildew as the other programs examined. Yields were not taken on these trials due to an unexpected early frost. Seedling bioassays are being conducted in NY, PA, MD, and VA to examine occurrence of reduced efficacy of fungicides. There are no results yet from the 2018 bioassays.Brief highlights of the 2017 bioassays include that on Long Island, the most effective fungicides (both doses) for downy mildew management were Bravo Ultrex (best), Zing!, Ranman, Zampro, and Previcur Flex. Forum and Curzate were effective at the first rating. Presidio, Revus, and Quadris were ineffective including when applied at the full label rate. In MD, Presidio (fluopicolide), Ranman (cyazofamid), Zing (zoxamide and chlorothalonil), and Curzate (cymoxanil) were consistent in both 2016 and 2017, greatly reducing cucurbit downy mildew symptoms. While Bravo Ultrex (chlorothalonil) and Plenaris (oxathiapiprolin), also performed well 2017, which was their first year in the bioassay. Revus (mandipropamid), Forum (dimethomorph), and Quadris (azoxystrobin) were ineffective at controlling cucurbit downy mildew. Interestingly, Previcur Flex at the half label rate in both 2016 and 2017 provided almost no reduction in downy mildew compared to the water control. However at the full label rate it resulted in close to complete reduction, suggesting that theP. cubensis populationhas some tolerance to the fungicide. Bioassays for powdery mildew resistance were also conducted in 2017 on Long Island. Highlights of our results are that Topsin M, Flint, and Endura were ineffective. Rally was effective at both rates tested (highest and lowest label rates), Torino, and Luna Privilege were effective at all rates. Quintec at all rates tested was phytotoxic causing leaves to turn yellow and then die. Sentinel plotswere also established formonitoring occurrence of downy mildew in different cucurbit crop types throughout the region to contribute information to theipmPIPEcucurbit downy mildew forecasting program. Currently we have one site on Long Island, NY and MA, two sites in PA and VA, and three sites in MD.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2018
Citation:
Wyenandt, C.A., McGrath, M.T., Everts, K.L., Rideout, S.L., Gugino, B.K., and Kleczewski, N. Fungicide resistance management guidelines for cucurbit downy and powdery mildew control in the mid-Atlantic and Northeast regions of the United States in 2018. Plant Health Progress. 19:34-36. (Information collected in this project, along with other information was used to help develop this publication https://doi.org/10.1094/PHP-12-17-0077-BR). The publication was made available for free to all stakeholders at Plant Health Progress.
|
Progress 09/01/16 to 08/31/17
Outputs
Target Audience:Our stakeholders are cucurbit growers, pest management advisors, consultants, extension educators, agricultural industry personnel, and beekeepers throughout the Northeast and mid-Atlantic regions and other locations with similar production systems. Within our research group, we all have partial extension appointments and regularly teach these stakeholder groups. Our project has been successfully initiated and as it progresses, it will improve in-season disease management decisions. It will enable growers to effectively manage pests while reducing pollinator exposure to key fungicides and our results will be incorporated into existing IPM programs that include the use of crop rotation, host resistance (when available), scouting, and disease and forecasting tools. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Professional development was provided in MA at a twilight meeting in September 2017 which was attended by over 50 growers and Agriculture service providers. We discussed the sentinel plots and research on using downy mildew-resistant cucumbers to reduce need for fungicides including chlorothalonil. Attendees increased their knowledge and understanding of cucurbit downy mildew biology and management and most reported they were likely to incorporate resistant varieties and/or alternative fungicide programs on their farms. One-on-one discussions were held with various student interns in PA, MD, and other states regarding the purpose of the established trial to evaluate the use of alternative fungicide programs that reduce the reliance on chlorothalonil for the management of powdery mildew on pumpkin. General concepts of the project and the use of bioassays to monitor and document fungicide resistance was included in course lectures for the Plant Science capstone Integrated Pest Management course (PA). There is one graduate student that is working on this project. He participated in developing and conducting surveys, extension presentations and research trials. How have the results been disseminated to communities of interest?The research results have been disseminated at several regional vegetable grower meetings and conferences. These meetings include the 2017 Mid-Atlantic Fruit and Vegetable Convention in Hershey, PA.; the 2016 Northeast Region Certified Crop Advisor training, Syracuse, NY; New Hampshire Giant Pumpkin Growers Association meeting, Goffstown, NH; New England Vegetable and Fruit Conference, Manchester, NH; Southeastern MA Ag & Food Conference, UMass Twilight Meeting; 39th Annual Fruit and Vegetable Growers Association of Delaware, Harrington, DE; Late Summer Vegetables Twilight Meeting, Queenstown, MD; WMREC Horticultural Crops Twilight Meeting/Tour, Keedysville, MD; and the Mt. Top Fruit and Vegetable Meeting, Accident, MD. Results were also disseminated throughout the season through one-on-one meetings and conversations with growers, and through regular extension activities. Information about fungicides and fungicide resistance is also frequently included in disease alerts and extension newsletter articles. Reports of downy mildew occurrence were submitted to the ipmPIPE cucurbit downy mildew forecasting program website. Information generated in this project, for example first reports of disease outbreaks, were disseminated to growers across the Northeast through the UMass Extension newsletter, Vegetable Notes, which has over 2,000 subscribers, and in DE and MD through the UD Weekly Crop update and UM Extension Vegetable and Fruit News, which collectively have more than 800 subscribers and are available on line, and to Long Island growers in several news articles in the weekly Long Island Fruit & Vegetable Update during the 2017 growing season. NY results from experiment conducted in 2016 were also published as: McGrath, M. T. and Sexton, Z. F. 2017. Evaluation of management programs without chlorothalonil for powdery mildew in pumpkin, 2016. Plant Disease Management Reports 11:V026. What do you plan to do during the next reporting period to accomplish the goals?We have collected data on efficacy of alternative fungicide programs (2 years), presence of resistance in P. cubensis and P. xanthii, and realistic levels of chlorothalonil to which honey bees would be exposed in cucurbit fields. In the third year of our project, we will obtain the gene expression data that will inform our crop specific recommendations on fungicide programs. In addition we will continue to obtain crop specific data on the efficacy of chlorothalonil alternatives and the presence of fungicide resistance through our field trials and bioassays. Our surveys have identified cucurbit grower's baseline knowledge on risk of fungicides to honey bees, and their knowledge of fungicide resistance. Building on our existing survey data, we will begin to develop factsheets, initial crop-specific guidelines for chlorothalonil alternatives, and other educational resources that will improve grower knowledge on reducing the need of unwarranted fungicide applications based on risk to honey bees, crop host susceptibility, fungicide efficacy, and reducing the potential for fungicide resistance development.
Impacts
What was accomplished under these goals?
The second year of this research project spanned Sept 1, 2016 to Aug 31, 2017. During this year we made progress on all of the stated goals. We continued the identification of non-target effects of chlorothalonil spray programs and combination spray programs on fungicide levels in pollen, and the effect of these field-realistic levels on honey bee susceptibility to Nosema ceranae. A series of cage studies were performed to determine the genetic response of bees fed field-relevant doses of fungicides, as compared to a control group. Five cups with 40 bees each, 4 experimental groups and one control group, were replicated twice in order to pool enough genetic material. Experimental groups were fed a diet of fungicide-doped pollen substitute and sugar syrup while the control was fed clean pollen substitute and sugar syrup. Pesticide doses were determined using real world contamination levels that we obtained from pollen hand collected from watermelon flowers treated with various fungicidal treatment regimes in 2016. Fresh diets were supplied daily throughout the course of the 7 day study. Serving bees were sacrificed, and are currently stored at -80C. These bees will be sequenced to explore differences in gene expression, specifically immune gene expression, between the experimental groups. Currently, we are awaiting results on the levels of fungicides in the doped pollen substitute. Should the results show the same field relevant levels, we will move forward with the genetic analyses. This work should be completed by March 2018. In addressing our second goal, we evaluated integrated disease management programs that reduce reliance on chlorothalonil for individual cucurbit species. The experiments were conducted in VA, MD, NJ, PA and NY. In PA and NY, the focus was on powdery mildew on pumpkin. These two states conducted a split plot randomized complete block trial with five replications, established at the Russell E. Larson Research and Education Center in PA Furnace, PA and at the Long Island Horticultural Research and Extension Center in Riverhead, NY. A cultivar with resistance to powdery mildew was compared to a susceptible cultivar. The whole plot treatment for these trials was cultivar (powdery mildew resistant cv. Bayhorse Gold and susceptible cv. Gold Challenger) and sub-plot was six fungicide treatments consisting of the following: untreated control, or powdery mildew specific fungicide program (Luna Experience, Vivando, Torino) tank mixed weekly with chlorothalonil (commercial standard), powdery mildew specific fungicide program with chlorothalonil alternative Tritek, Bravo Weather Stik alone, Microthiol Disperss alone, TriTek alone. Powdery mildew was first observed in PA in the trial on 17 Jul. Powdery mildew severity was rated on a continuous scale of 0 to 100% based on the percentage of upper and lower leaf surface (rated separately) showing symptoms on six leaves per plot on 29 Jul, 10, 16, and 23 Aug and the area under the disease progress curve (AUDPC) was calculated at the end of the season. The substitution of Tritek (@ 2 gal/100 gal) for Bravo Weather Stik (2.0 pt/A) as the protectant for resistance management in the powdery mildew specific fungicide program did not negatively affect powdery mildew management on either the upper or lower leaf surface. At the NY location, the cv. Bayhorse Gold, was not effective in reducing powdery mildew severity at any assessment time when compared to the horticulturally-similar susceptible cv. Gold Challenger. In the examination of the alternative multi-site mode of action fungicides, Microthiol Disperss was as effective as Bravo Ultrex across all measurements of severity as well as defoliation and fruit handle quality. Tritek effectively managed powdery mildew, but not quite as well on upper leaf surfaces as Bravo Ultrex or Microthiol Disperss; however, it was the most effective for powdery mildew on lower leaf surfaces while Bravo Ultrex was ineffective. Surprisingly, Tritek was least effective of the three while Microthiol Disperss was best for preserving handle quality. The fungicide programs tested consisted of rotation of Luna Experience, Vivando, and Torino. These single-site mode of action fungicides were tank mixed with a contact fungicide. Powdery mildew was more effectively controlled on lower leaf surfaces when Microthiol Disperss or Tritek was used rather than Bravo for all but the last application. In conclusion, the two Bravo alternatives tested were found to be more effective fungicides for managing powdery mildew than Bravo. Bravo has activity for a broader spectrum of fungal pathogens and thus is a better choice when other diseases are occurring. In MD, we assessed three melons, which varied in their susceptibility to powdery mildew (PM), anthracnose and gummy stem blight (GSB): Crunchy Red, Citrullus lanatus which is susceptible (S) to anthracnose and GSB; Snow Leopard, Cucumis melo var. inodorus, S to PM; and Athena, Cucumis melo var. reticulatus, moderately resistant (MR) to PM. In addition, the efficacy of chlorothalonil in comparison to Regalia (plant extract of Reynoutria sachalinensis), Oso (polyoxin D zinc salt) and conventional fungicides was also evaluated. Anthracnose, GSB, and PM were the most severe diseases observed in 2017. Oso, Bravo, commercial standard without Bravo, and the commercial standard programs resulted in similar levels of GSB in muskmelon and watermelon, Oso and Bravo programs reduced GSB similarly in honeydew melon, while the commercial standard and commercial standard without Bravo had the lowest level of GSB severity in honeydew. PM severity was similar in the commercial standard and commercial standard without Bravo programs in managing disease. The similar performance of the commercial standard and commercial standard without Bravo treatments suggest that alternatives to chlorothalonil can be effective, when tank mixed with targeted fungicides. We continued trials to determine the current breadth of fungicide resistance in both Pseudoperonospora cubensis populations across the mid-Atlantic and Northeast region. Similar bioassays were conducted in five states. Briefly cucumber seedlings (cv. Silver Slicer) at about the 2-leaf stage were sprayed with various fungicides at full and half label rates with a backpack sprayer or hand held spray bottles. The next day, four groups of seedlings (replications) were put in different areas of either a field experiment or commercial field to evaluate fungicide resistance. Seedlings in experiments were placed in plots where no fungicides had been applied. In PA, NY, and MD two cucumber bioassays were conducted in 2017. In PA the most effective products were Orondis, Ranman, and Zing! at both rates and locations. In NY the most effective fungicides (both rates) were Bravo Ultrex (best), Zing!, Ranman, Zampro, and Previcur Flex. In MD the most effective products were Orondis, Ranman, Presidio and Zing. Previcur Flex at the half rate, resulted in over 100% disease severity compared to the water control. To evaluate the occurrence of resistance and reduced sensitivity of cucurbit powdery mildew (Podosphaera xanthii) population to fungicide, pumpkin bioassays (cv. Gold Challenger) were conducted is a similar manner as the cucumber downy mildew bioassays. In PA, a total of nine fungicides were evaluated at one to three rates. Six of the nine fungicides including Torino, Bravo Weather Stik, Vivando, Quintec and Rally were very effective at managing powdery mildew. Topsin M and Flint were not effective. Endura was moderately effective. In NY, Topsin M, Flint, and Endura were ineffective. Rally was effective at both rates tested (highest and lowest label rates). Vivando, Torino, and Luna Privilege were effective at all rates tested (label, half, and quarter rates; hi, low and quarter of hi rates for Luna Privilege).
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Progress 09/01/15 to 08/31/16
Outputs
Target Audience:Our stakeholders are cucurbit growers, pest management advisors, consultants, extension educators, agricultural industry personnel, and beekeepers throughout the Northeast and mid-Atlantic regions and other locations with similar production systems. Within our research group, we all have partial extension appointments and regularly teach these stakeholder groups. Our project has been successfully initiated and as it progresses, it will improve in-season disease management decisions. It will enable growers to effectively manage pests while reducing pollinator exposure to key fungicides and our results will be incorporated into existing IPM programs that include the use of crop rotation, host resistance (when available), scouting, and disease and forecasting tools. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Although only in the first year of the project, some informal training has been conducted. As part of a field trip for a group of underrepresented minority students participating in a NIFA-funded Undergraduate Research and Extension Experiential Learning Fellowship, the field trial established to evaluate the use of alternative fungicide programs that reduce the reliance on chlorothalonil for the management of powdery mildew on pumpkin, served as the backdrop for a discussion about the importance of pollinators in pumpkin production, concerns about pollinator health and the objective of the trial to reduce pollinator exposure to chlorothalonil. Similar one-on-one discussions regarding the purpose of the field trial were also conducted with two interns participating in the Gugino vegetable research program this summer. One intern from the University of Puerto Rico, Mayaguez campus participating in the Summer Research Opportunities Program at Penn State and the other conducting an independent internship from the Pennsylvania College of Technology. How have the results been disseminated to communities of interest?Introductory presentations of the goals, and discussion of the background, of the project were made at a conference and two twilight meetings in the fall 2015-fall 2016 reporting season. Scheufele presented 'Integrated Pest Management in Cucurbits' at the Northeast Organic Farming Association Summer Conference, August 12, 2016. Amherst, MA. It was attended by 30 people. She also has one upcoming presentation at the Applied Research at UMass Twilight Meeting, 'Cucurbit IPM Trials,' on September 14, 2016, S. Deerfield, MA. Everts also presented 'Cucurbit IPM trials and reducing pollinator exposure to key fungicides' at a Twilight Tour at the University of Maryland's Lower Eastern Shore Research and Education Center on Aug 10, 2016, which was attended by 25 people. What do you plan to do during the next reporting period to accomplish the goals?In the second year of the project, we will use the information on fungicide contamination from pollen collected from the chlorothalonil level trial, which is now being analyzed. The levels produced under five different fungicide programs will be used to spike pollen to contain comparable levels, and to test in replicated feeding trials on Apis mellifera. We will continue the replicated field trials on alternatives to currently prescribed fungicide programs. In our second year we will also continue to conduct cucurbit downy mildew and additionally add powdery mildew bioassays to assess occurrence of resistance and reduced sensitivity to fungicides in P. cubensis and P. xanthii populations. A survey will be sent to cucurbit growers across all seven participating states, in order to collect data on the regional impacts of cucurbit production on honey bees, and to document grower needs on a wide range of cucurbit crops, production systems, and scales. This data will be used to identify gaps in grower knowledge, barriers to implementing IPM in cucurbit production, estimate impacts of pesticide use on bees and other non-target organisms, and to develop educational/extension programming (e.g. workshops, presentations, factsheets, webinars) which address identified needs. Our results in of replicated field trials from years 1 and 2 will assist in the preliminary development of crop specific guidelines. In addition, we will begin the development of outreach tools that inform growers of management programs that reduce chlorothalonil use and risk to honey bees, reduce the need of unwarranted fungicide applications based on host susceptibility, and reduce the potential for fungicide resistance development.
Impacts
What was accomplished under these goals?
The first year of this research project spanned Sept 1 2015 to Sept 1 2016. During this first year conference calls were held approx. every two months to coordinate activities. Briefly the following experiments were initiated. We have completed significant groundwork to evaluate the impact of fungicides on honey bee susceptibility to Nosema ceranae. An experiment to evaluate three fungicides was conducted as a randomized complete block at the University of Maryland's Research and Education Center in Georgetown. These three fungicides represent groups that have been associated, in previous research, with varied mortality at the colony level. We treated watermelon with either chlorothalonil, pyraclostrobin + boscalid (Pristine), or triflumazole (Procure) at label rates and levels representative of a high, but realistic production level. The fungicides tested are in groups C2 (complex II: succinate dehydrogenase), C3 (complex III: cytochrome bc1 at Qo site); G1 (C14-demethylase in sterol biosynthesis) and M multisite contact activity. Using undergraduate students we looked at various ways to remove pollen from watermelon anthers. Several different techniques were attempted, which tried to balance the needs for pollen uncontaminated with other plant materials and practical considerations needed to ensure we get 3 grams of pollen. We successfully collected pollen from all treatments and are now sending those in for analysis. This sample analysis results will enable us to design cage trails next year that will expose honey bees to corresponding representative fungicide contaminated pollen samples. We conducted field trials across five states for individual cucurbit species to evaluate integrated disease management programs that reduce reliance on chlorothalonil. These trials were conducted in Virginia, Maryland, New Jersey, Pennsylvania, and New York and evaluated the use of alternative fungicide programs on melon, watermelon, squash, cucumber and pumpkin. In Pennsylvania and New York, the focus disease was powdery mildew on pumpkin; In Maryland it was powdery mildew on melon, and gummy stem blight on watermelon, in New Jersey it was powdery mildew on summer squash; and in Virginia it was downy mildew on cucumber. These trials were conducted as split plot randomized complete block trial or randomized complete block design with four replications. In Pennsylvania and New York the whole plot was cultivar (powdery mildew resistant cv. Bayhorse Gold and susceptible cv. Gold Challenger) and sub-plot was six fungicide treatments consisting of either chlorothalonil or alternative products that were applied alone or in combination. The alternatives are Microthiol Disperss (sulfur) and TriTek (mineral oil), which are being tested alone compared to Bravo (chlorothalonil) and in a combination program with other fungicides that have targeted activity for powdery mildew. These experiments are ongoing. Additional alternatives products Regalia (plant extract of Reynoutria sachalinensis), Oso (polyoxin D Sinc salt), and conventional fungicides were tested in Maryland. Cucurbit downy mildew bioassays to assess occurrence of resistance and reduced sensitivity to fungicides were also conducted (or are ongoing) across the region. Three cucumber bioassays are in the process of being conducted across Pennsylvania in northwestern, central and southeastern regions of the state; one bioassay has been completed in Maryland and a second is ongoing. Additional bioassays are planned in New York, New Jersey and Virginia. Briefly, the occurrence of resistance and reduced sensitivity of the Pseuodoperonspora cubensis population to fungicides, is being assessed as follows. A total of ten different fungicides are being evaluated at two different rates (high label rate equivalent and half the label rate) along with an untreated control. Each set of bioassay plants cv. Silver Queen or Straight Eight includes four replicates for a total of 84 plants per bioassay. Plants are placed in the field for 48 hours, the plants are moved back into the greenhouse and two additional non-treated plants are placed along with the bioassay plants to monitor for plant-to-plant spread. After 5 to 7 days, each plant is rated on a 0 to 100% scale in 5% increments for disease severity plus 1% for trace disease severity. Early results have demonstrated high levels of resistance or insensitivity to currently used fungicides. Sentinel plots for the spread of downy mildew have been planted and maintained in five states for cucurbit downy mildew onset on different cucurbit crops.
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