Progress 10/01/16 to 09/30/20
Outputs
Target Audience:Audiences targeted to receive information generated from this project included onion growers, University extension educators and faculty, professional crop consultants, agri-chemical company representatives, vegetable seed company representatives and the public. Efforts to transfer knowledge about our research have focused primarily on verbal presentations at stakeholder-based meetings, extension educator-based meetings, on-farm visits and extension newsletters and magazines. Changes/Problems:No onion thrips populations in New York State that we examined were resistant to spinetoram. Consequently, we were not able to address objectives 3 and 4 because they involved determining the mechanism and genetics of resistance to spinetoram in onion thrips populations. What opportunities for training and professional development has the project provided?The project involved mentoring one technician, one graduate student and an undergraduate student over the course of this project. How have the results been disseminated to communities of interest?Results have been disseminated to several communities of interest including the general public, onion growers and the scientific community. The following are examples of the communities and information shared. Results from our project have been discussed with the New York onion industry via multiple oral presentations at Cornell Cooperative Extension regional meetings as well as nationally at professional entomology meetings. Results have been reported via written articles in a Cornell Cooperative Extension newsletter and the popular trade magazine, Onion World. In all cases, our results showing that there is no resistance to spinetoram in onion fields suggests that our current insecticide resistance management program for onion thrips using selective insecticides and action thresholds is likely mitigating resistance development. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
The susceptibility of onion thrips to spinetoram was assessed from populations collected in commercial onion fields in New York. LC50s for adults were generated from feeding assays and ranged from 2.07-5.08 ppm, but grower reports indicated that onion thrips populations continue to be susceptible to spinetoram. Moreover, both regional and temporal variation in susceptibility were similar among these populations based on survival at individual concentrations tested, despite significant differences in LC50s. These results suggest some genetic heterogeneity among onion thrips populations and serve as a valuable reference for the continued monitoring of onion thrips susceptibility to spinetoram, contributing to ongoing efforts to manage insecticide resistance in this system. Additionally, the performance of three types of laboratory bioassays were compared to identify which was best for determining onion thrips sensitivity to spinetoram (Radiant SC), a commonly used insecticide in New York onion fields. Assays included TIBS (Thrips Insecticide Bioassay System - a contact assay), a feeding-only assay, and a leaf dip assay (contact + feeding). We wanted to understand how different types of exposure to spinetoram via these assays influenced thrips morality, the assay that generated an LC50 with relatively low 95% confidence intervals and which bioassay was easiest to use. A susceptible colony of onion thrips from Elba, NY was used for all assays. Assays were conducted by placing varying numbers of adult thrips in vials or petri dishes that contained 7-8 rates of spinetoram (range: 0.01 to 100 ppm) and an untreated control. Results indicated that all three assays had significantly different dose-mortality relationships and LC50s. The feeding-only assay had the highest LC50 (1.63 ppm), while those that included contact were much lower (0.014 ppm and 0.045 ppm for leaf dip and TIBS assays, respectively). The leaf dip assay had the smallest 95% confidence interval (0.009-0.022 ppm). These results suggested that contact with spinetoram had a greater impact on thrips mortality than their exposure to spinetoram only via feeding. Results from a field simulation experiment with spinetoram generated an LC50 of 1.58, which was very similar to the LC50 generated from the feeding-only assay. Finally, the feeding-only assay was the easiest to set up and took less time to collect data than the other assays. Our results will be communicated to extension educators and crop consultants so that they can use the feeding-only assay to monitor resistance to spinetoram in the future. Finally, results from this project were considered when revising guidelines for managing onion thrips with insecticides in commercial onion fields https://rvpadmin.cce.cornell.edu/uploads/doc_900.pdf.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Moretti, E. A., and B. A. Nault. 2019. Onion thrips control in onion, 2017. Arthropod Management Tests, 44(1): DOI 10.1093/amt/tsz003.
- Type:
Other
Status:
Published
Year Published:
2019
Citation:
Moretti, E., and B. Nault. 2019. Monitoring onion thrips susceptibility to Radiant SC. Cornell Cooperative Extension, Cornell Vegetable Program. VegEdge 15(24): 6-7.
- Type:
Other
Status:
Published
Year Published:
2019
Citation:
Moretti, E., and B.A. Nault. 2019. Are onion thrips developing resistance to Radiant SC? Onion World. 35(8): 6-8.
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Moretti, E. A., R. S. Harding, J. G. Scott and B. A. Nault. 2019. Monitoring onion thrips (Thysanoptera: Thripidae) susceptibility to spinetoram in New York onion fields. J. Econ. Entomol. 112(3): 14931497.
- Type:
Other
Status:
Published
Year Published:
2020
Citation:
Nault, B., and C. Hoepting. 2020. Insecticide programs to consider for onion thrips control in onion in 2020. VegEdge 16(14): 8-9.
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2020
Citation:
Yannuzzi, I. 2020. Comparison of bioassays used to monitor onion thrips (Thrips tabaci) susceptibility to spinetoram. Honors thesis. April 2020. Cornell University, Ithaca, NY.
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Progress 10/01/18 to 09/30/19
Outputs
Target Audience:Audiences targeted to receive information generated from this project included onion growers, University extension educators and faculty, professional crop consultants, agri-chemical company representatives, vegetable seed company representatives and the public. Efforts to transfer knowledge about our research have focused primarily on verbal presentations at stakeholder-based meetings, extension educator-based workshops, on-farm visits and extension newsletters and magazines. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?The project involved mentoring one technician, one graduate student and an undergraduate student in 2019. How have the results been disseminated to communities of interest?Results from our project were discussed with the New York onion industry. Oral presentations were given at Cornell Cooperative Extension regional meetings. Written information was presented at a professional conference as well as a Cornell Cooperative Extension newsletter and a popular trade magazine. In all cases, our results showing that there is no resistance to spinetoram in onion fields suggests that our current insecticide resistance management program for onion thrips using selective insecticides and action thresholds is mitigating resistance development. What do you plan to do during the next reporting period to accomplish the goals?Plans for the next reporting period include repeating the field simulation experiment to related bioassay results with mortality levels of onion thrips on spinetoram-treated onion plants. Additionally, we intend to publish the this study. If time permits, a diagnostic dose, estimated to kill 90% of thrips, will be used to predict control failures in fields across the region.
Impacts
What was accomplished under these goals?
In 2019, the performance of three types of insecticide sensitivity bioassays were compared for use with onion thrips: TIBS (Thrips Insecticide Bioassay System - a contact assay), s feeding-only assay, and s leaf dip assay (contact + feeding). We wanted to understand how different types of exposure to insecticides via these assays influenced thrips morality, the assay that generated an LC50 with relatively low 95% confidence intervals and which bioassay was easiest to use. A susceptible colony of onion thrips from Elba, NY and spinetoram (Radiant SC), a commonly used insecticide in New York onion fields, were used for all assays. Assays were conducted by placing varying numbers of adult thrips in vials or petri dishes that contained 7-8 rates of spinetoram (range: 0.01 to 100 ppm) and an untreated control. Results indicated that all three assays had significantly different dose-mortality relationships and LC50s. The feeding-only assay had the highest LC50 (1.63 ppm), while those that included contact were much lower (0.014 ppm and 0.045 ppm for leaf dip and TIBS assays, respectively). The leaf dip assay had the smallest 95% confidence interval (0.009-0.022 ppm). These results suggested that contact with spinetoram had a greater impact on thrips mortality than their exposure to spinetoram only via feeding. Results from the field simulation experiment generated an LC50 of 1.58, which was very similar to the LC50 generated from the feeding-only assay. Finally, the feeding-only assay was the easiest to set up and took less time to collect data than the other assays. Our results will be communicated to extension educators and crop consultants so that they can use the feeding-only assay to monitor resistance to spinetoram in the future.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Moretti, E. A., R. S. Harding, J. G. Scott and B. A. Nault. 2019. Monitoring onion thrips (Thysanoptera: Thripidae) susceptibility to spinetoram in New York onion fields. J. Econ. Entomol. 112(3): 14931497.
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Moretti, E. A., and B. A. Nault. 2019. Onion thrips control in onion, 2017. Arthropod Management Tests, 44(1), 12 doi: 10.1093/amt/tsz003.
- Type:
Other
Status:
Published
Year Published:
2019
Citation:
Moretti, E., and B. Nault. 2019. Monitoring onion thrips susceptibility to Radiant SC. Cornell Cooperative Extension, Cornell Vegetable Program. VegEdge 15(24): 6-7.
- Type:
Other
Status:
Published
Year Published:
2019
Citation:
Moretti, E., and B.A. Nault. 2019. Are onion thrips developing resistance to Radiant SC? Onion World. 35(8): 6-8.
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Progress 10/01/17 to 09/30/18
Outputs
Target Audience:Audiences targeted to receive information generated from this project included onion growers, University extension educators and faculty, professional crop consultants, agri-chemical company representatives, vegetable seed company representatives and the public. Efforts to transfer knowledge about our research have focused primarily on verbal presentations at stakeholder-based meetings, extension educator-based workshops and on-farm visits. Changes/Problems:To date, no onion thrips populations examined in our project have been identified as resistant to spinetoram. If results are similar in 2019, we will not be able to address Objectives 3 and 4 because they involve determining the mechanism and genetics of the resistance. What opportunities for training and professional development has the project provided?The project involved mentoring one technician and one graduate student in 2018. How have the results been disseminated to communities of interest?Results from our project were discussed briefly with the New York onion industry. Oral presentations were given at three formal Cornell Cooperative Extension regional meetings and one twilight meeting during the summer in 2018. Management of onion thrips using selective insecticides and action thresholds was also communicated to the New York onion industry via Cornell Cooperative newsletters and to subsets of growers in various Upstate New York regions. What do you plan to do during the next reporting period to accomplish the goals?Plans for the next reporting period include relating bioassay results with mortality levels of onion thrips on spinetoram-treated onion plants. Additionally, a new project will compare results of three different bioassay methods to determine which bioassay is most appropriate for monitoring onion thrips susceptibility to spinetoram. Suitability will be determined based on several factors, including resources, time, convenience, and relationship of bioassay generated mortality levels with mortality levels observed on treated onion plants. If time permits, a diagnostic dose, estimated to kill 90% of thrips, will be used to predict control failures in fields across the region.
Impacts
What was accomplished under these goals?
Onion thrips populations were collected from commercial onion fields in two geographic regions in 2018 and examined for their susceptibility to spinetoram. Each field was separated from other onion fields to ensure that they were not managed by the same onion grower. We hypothesized that onion thrips populations would be less sensitive to spinetoram in the Elba muck region compared with all other regions because populations likely have been exposed more frequently to spinetoram. Thus, we anticipated that LC50s would be higher in the Elba populations than the others. LC50s for adults were generated from adult feeding assays and ranged from 2.07-5.08 ppm, but grower reports indicated that onion thrips populations continued to be susceptible to spinetoram. Moreover, both regional and temporal variation in susceptibility were similar among these populations based on survival at individual concentrations tested, despite significant differences in LC50s. These results suggested some genetic heterogeneity among onion thrips populations, but populations from Elba were not less susceptible than those from other regions. These data will serve as a valuable reference for the continued monitoring of onion thrips susceptibility to spinetoram, contributing to ongoing efforts to manage insecticide resistance in this system. While these results are excellent news for New York onion growers, we will continue to stress the importance of not relying exclusively on spinetoram to manage onion thrips infestations. We will encourage growers to use spinetoram in a prescribed sequence with insecticides belonging to different classes during the season. Moreover, we will continue to encourage growers to adopt action thresholds to determine if and when insecticide applications are needed, rather than rely on a weekly spray schedule.
Publications
- Type:
Journal Articles
Status:
Accepted
Year Published:
2019
Citation:
Moretti, E.A., Harding, R.S., Scott, J.G., and B.A. Nault. 2019. Monitoring onion thrips (Thysanoptera: Thripidae) susceptibility to spinetoram in New York onion fields. J. Econ. Entomol. (in press)
- Type:
Journal Articles
Status:
Awaiting Publication
Year Published:
2019
Citation:
Moretti, E.A., and Nault, B.A. (2019). Onion thrips control in onion, 2017. Arthropod Management Tests. (In press)
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Progress 10/01/16 to 09/30/17
Outputs
Target Audience:Audiences targeted to receive information generated from this project included onion growers, University extension educators and faculty, professional crop consultants, agri-chemical company representatives, vegetable seed company representatives and the public. Efforts to transfer knowledge about our research have focused primarily on verbal presentations at stakeholder-based meetings, extension educator-based workshops and on-farm visits. Changes/Problems:To date, no onion thrips populations examined in our project have been identified as resistant to spinetoram. If results are similar in 2018, we will not be able to address objectives 3 and 4 because they involve determining the mechanism and genetics of the resistance. What opportunities for training and professional development has the project provided?The project involved mentoring one technician and one graduate student in 2017. How have the results been disseminated to communities of interest?Results from our project were discussed briefly with the New York onion industry. Oral presentations were given at three formal Cornell Cooperative Extension regional meetings and one twilight meeting during the summer in 2017. Management of onion thrips using selective insecticides and action thresholds was also communicated to the New York onion industry via Cornell Cooperative newsletters and to subsets of growers in various Upstate New York regions. What do you plan to do during the next reporting period to accomplish the goals?Plans for the next reporting period include repeating the research that was conducted in 2017 as well as continuing to disseminate results from these studies to the US onion industry, especially the onion growers in New York.?
Impacts
What was accomplished under these goals?
Onion thrips populations were collected from 8 commercial onion fields in 2017 and examined for their susceptibility to spinetoram. In 2017, 3 fields were located in the Elba muck, which is the second largest contiguous muck area in New York and home to the second largest onion production area in the state. Each field was in proximity to other onion fields that may or may not have been managed by the same onion grower. The remaining 5 onion fields were located throughout central and western New York and were on much small mucks than the Elba muck and all fields were separated from other onion grower's fields. We hypothesized that onion thrips populations would be less sensitive to spinetoram in the Elba muck compared with the other locations because populations likely have been exposed more frequently to spinetoram. Thus, we anticipated that LC50s would be higher in the Elba populations than the others. Using an ingestion-based feeding bioassay for 48 hours, LC50s and 95% confidence intervals were determined for each thrips population. Overall, the mean LC50 for all 8 populations was 2.9 µg/ml (range: 1.8 to 3.5 µg/ml) and mean 95% confidence intervals were 2.2 to 21.4 µg/ml. The LC50s from populations in the Elba muck and those from the other areas were 2.9 µg/ml and 2.8 µg/ml, respectively. The estimated field dose of spinetoram applied to onion is approximately 18 µg/ml (this would be a 6 fl oz per acre rate applied in a spray volume of 30 gallons per acre). Therefore, our results indicate that all onion thrips populations examined were susceptible to spinetoram and that no differences in susceptibility existed among Elba populations and those in smaller mucks throughout Upstate New York. While these results are excellent news for New York onion growers, we will continue to stress the importance of not relying exclusively on spinetoram to manage onion thrips infestations. We will encourage growers to use spinetoram in a prescribed sequence with insecticides belonging to different classes during the season. Moreover, we will continue to encourage growers to adopt action thresholds to determine if and when insecticide applications are needed, rather than rely on a weekly spray schedule.
Publications
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