LIFE SYSTEMS AND MANAGEMENT OF ARTHROPOOD PESTS AFFECTING AGRICULTURAL CROPPING SYSTEMS

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 1020414
• Project Start Date: Oct 1, 2019
• Project End Date: Sep 30, 2024
• Program Code: [(N/A)]- (N/A)

Recipient Organization
NORTH CAROLINA STATE UNIV
(N/A)
RALEIGH,NC 27695

Performing Department
Entomology and Plant Pathology

Non Technical Summary
Vegetable and agronomic crops are attacked by a diverse complex of insect pests, which if not managed effectively, can greatly reduce yields and quality, and at times completely destroy the market value of the crop. Insect management in most of these crops relies heavily on the use of chemical insecticides to prevent reductions in yield and quality. Although advances in pesticide chemistry have resulted in the adoption of more selective insecticides that have fewer non-target effects but they still pose potential risk to farm workers and the environment. As a result there is growing demand for produce and agricultural products grown using clearly defined "best management practices" including reduced risk pest management systems that mitigate the environmental impacts and health risks of agriculture. In addition, pest adaptation to crop protection measures leading to resistance is becoming a major problem. In the diverse agroecosystems populations of many pest species attack multiple crops produced in the area, and move freely among different crops. Consequently, production and pest management practices implemented in one crop often have profound effects on the timing and size of the pest populations that develop in vegetable crops.The development of insect management systems that minimize use of chemical insecticides requires in-depth understanding of the ecology, behavior and population biology of the pest species and their natural enemies, not only in the crop to be managed but also in the other relevant components of the agroecosystem. Reduced-risk insect management systems of the future will be designed to maximize environmental resistance to the development of pest populations through the more extensive use of currently available cultural and biological measures and the adoption of new practices and technologies to avoid or suppress damaging pest populations applied on the basis of real-time information on the status of the crop and its pests, and reliable projections of the likelihood that economic damage to the crop will occur in the absence of pest management interventions. Research under this project will be directed towards the goal of developing knowledge, strategies and tactics to improve the efficiency and sustainability of arthropod management in vegetable and agronomic cropping systems during a period of rapid technological innovation. The particular crops and insect systems to be investigated during the life of this project will depend on will be their importance and the potential for making significant advances within a reasonable timeframe. Primary focus will be on the development of reduced risk practices for sustainable management of arthropod pests of vegetable crops and decision aids to assist growers in making informed decisions regarding selection and implementation of pest management measures and inform resistance management strategies.

Animal Health Component

50%

Research Effort Categories

Basic

30%

Applied

50%

Developmental

20%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
211	1499	1130	100%

Knowledge Area
211 - Insects, Mites, and Other Arthropods Affecting Plants;

Subject Of Investigation
1499 - Vegetables, general/other;

Field Of Science
1130 - Entomology and acarology;

Keywords

pest management

insecticide resistance

pest management decision aids

thrips

spidermites

Goals / Objectives
Goal: Develop knowledge, strategies and tactics to improve the efficiency and sustainability of arthropod management in vegetable and agronomic cropping systems during a period of rapid technological innovation.Objectives1. Development of reduced risk practices for management of arthropod pest of selected crops and cropping systems; based on improved understanding of the life systems of important pest species affecting selected crops and cropping systems.2. Development of decision aids to assist growers in making informed decisions regarding selection and implementation of pest management measures and inform resistance management strategies.

Project Methods
Research to develop durable, reduced risk, insect management systems for vegetable crops will be conducted throughout the duration of this project, primarily on commercial farms and university agricultural research stations. These systems will be designed to maintain insect pest populations at sub-economic levels while minimizing adverse environmental impacts due to off-target effects and human health risks associated with exposure to pesticides by farm workers and to pesticide residues by consumers. Because the populations of many important arthropod pests attacking specific crops often develop in other crops and/or in natural vegetation during a portion of the year, knowledge of how the effects of production and pest management practices one crop affect population dynamics and dispersal of such pests into other crops is critically important to the development and implementation of durable and effective management systems for these pests. Research will emphasize understanding pest life systems and the pest-crop interactions that transcend a single crop and result in crop loss. One important area of focus will be on characterizing the genetic structure of populations of key pest species, in which insecticide resistance is a frequent problem (e.g. thrips, whitefly, mites), in relation to geographic distance, habitat and host crop, and over time. To accomplish this, a variety of molecular genetic markers will be used (e.g. CO1, microsatellite, SNP). The resulting information will inform decisions regarding the appropriate scale over which resistance management programs should be implemented. Other areas of research will include optimizing naturally occurring biological control alone and in combination with selective insecticides, resistance management and the development and evaluation of procedures for determining the need to apply remedial control measures (e.g. pest and crop monitoring, sampling and thresholds). In addition, research will include the evaluation of new reduced risk technologies including conventionally developed and transgenic insect resistant crop genotypes and the use of selective, systemic insecticides applied through drip irrigation systems and as seed treatments. A combination of field and laboratory, observational and experimental approaches will be used to identify potentially important relationships and interactions, and to formulate and subsequently test hypotheses regarding critical relationships and management approaches. The specific crops, cropping systems, pests, and pest complexes will be selected for investigation based on consultation with extension agents, growers and crop consultants, and by significant changes in the pest situation that may occur in vegetable crops.Modern, reduced risk approaches to insect management that are replacing older, broad spectrum insecticides are management-intensive, requiring the integration of multiple tactics implemented at the proper time and in combinations or sequences appropriate to the pest complex that is present. Research under this objective will focus on identification of crop production factors (e.g. field site characteristics, planting patterns, planting and harvest date, variety selection, irrigation, crop rotations, tillage, weed and disease management practices) and weather conditions that influence the timing and intensity of insect problems. These will be identified through analysis of publically available crop, land-use and pesticide-use, geo- referenced datasets. Extensive surveys of commercial production fields will be conducted as needed to obtain data on additional relevant production practices and crop/pest management inputs and on pest status and/or damage. These efforts will focus initially on thrips and spidermites, although other arthropod pests may be investigated. The resulting datasets will be summarized and analyzed using a combination of GIS and multivariate analyses to identify potential associations between weather, crop production and pest management practices, and agroecosystem structure with the timing and intensity of pest infestations and damage. A combination of field, greenhouse and laboratory experiments, as appropriate, will be conducted to further evaluate and validate potentially important associations. Models to predict risk of experiencing damaging populations of the targeted pest or pest complex, or risk of developing resistance to crop protection measures will be developed using these results. Published information on the impact of available arthropod pest management practices will be reviewed. In addition field experiments will be conducted to identify the impact of practices on crop loss for which robust information is lacking. A matrix that illustrates the expected benefit (yield loss prevented) of implementing insect management inputs applied alone and in combination will be developed. An interactive, risk-prediction model and pest management decision aid will be produced and made available on the internet for use by growers, crop consultants, and extension agents in assessing projected risk of crop loss and the reduction in risk associated with implementation of differing combinations of management practices.

Progress 10/01/19 to 09/30/20

Outputs
Target Audience:North Carolina vegetable and field crop growers, county extension agents with responsibilities for crop protection, and crop consultants reached through individual contacts, presentations at field programs and at the North Carolina Association of Crop Advisors annual meeting. Research and extension scientists, graduate students working on insect management in agricultural crops through presentations at the Annual Meeting of the Entomological Society of America, the Beltwide Cotton Conferences, the International Symposium of Thysanoptera and Tospoviruses. Direct interactions with farmer collaborators on whose farms we conducted research. Research and extension scientists and students throughout the world through publication of research papers. Scientists in the crop protection industry through meetings with scientists at Bayer Crop Science, Syngenta Crop Protection, Agbiome, and BASF. Changes/Problems:Research was halted completely for approximately 5months and attendance at scientific and other stakeholder meetings was greatly curtailed in 2020 due to Covid-19 restrictions. Although activities have increased,as of Feb 2021 many research activities have not yet resumed due to the needto maintain social isolation.It is hoped that this will improve in the coming months. What opportunities for training and professional development has the project provided?Five PhD students, two MS student, one post-doctoral research scientists were involved in various aspects of this project. Research findings relating to the MON 88702 cotton effects on thrips and thrips damage to cottonwerepresented to extension specialists and agents, crop advisors and the crop protection industry representatives at the national Beltwide Cotton Conferences, the NC Association of Crop Advisors. How have the results been disseminated to communities of interest?Presentations to scientists at the International Symposium of Thysanoptera and Tospoviruses, the Annual Meeting of the Entomological Society of America and the NC Association of Crop Advisors. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Objective 1. Tobacco thrips is the major pest of seedling cotton in the eastern U.S. cotton production regionsis the. As such it is the target of insecticide treatments applied to with almost 100% of the cotton acreage. Regulatory approval is pending for transgenic cotton expressing the novel modified Bt protein Cry51Aa834-16, which protects cotton seedlings from damage due to feeding by tobacco thrips. Effortshave focused on characterizing direct impacts of this Bt cotton (MON 88703) on the target thrips pest species(tobacco thrips and western flower thrips) in 2019-20; future efforts will include impacts on beneficial insects. A series of experiments revealed that MON 88702 cotton suppresses damage by reducing infestatons of both species but does so in a very differentway. Although egg laying by both species is greatly suppressed on MON 88702 plants,the effect is greater on western flower thrips than tobacco thrips. In addition, western flower thrips larvae dieafter feeding MON88702, whereastobacco thrips larvae are complete development to adult.This differences is important. Although western flower thrips is a pest of cotton in portions of the cotton belt, iin western US cotton production regionsis not a significant pest but isan important predator contributing to biological control of spidermiteand whitefly pests of cotton These novel modes of action also have the potential to create new challenges in developing effective resistance management plans for thrips andMON 88702 cotton. Genetically engineered cotton and corn expressing Bt coxins are widely grown in the USA but resistance by one targeted pest, Helicoverpa zea (cotton bollworm), has become an increasingly important problem that is resulting in increased insecticide use on cotton. This resistne is also undermining the area-wide suppression ofH. zea populations resulting from widespread planting of Bt crops that has reduced pest damage and insecticide use in many non-Bt vegetable crops grown in the eastern USA. Defined areas of non-Bt corn are mandated by EPA to offset selection for Bt toxin resistance that occurs in Bt corn, but no such refuge is required for Bt cotton, rather it is assumed that the array of non-Bt crop and non-crop hosts of H. zea that are abundant throughout US cotton production regions are sufficient to offset selection for resistance in Bt cotton. Astudycompleted in 2020 documented resistance levels of H. zea from 59 locations across North and South Carolina. These findings also revealedthat the effectiveness of this natural refuge in suppressing resistance evolution is highly variable across the study region. Further analyses are underway to relate this variation to the abundance of Bt crops as well as the total area of natural refuge and the abundance of non-Bt crops that contribute to the natural landscape. Objective 2. Research was initiated to improve an on-line pest management decision aid that we developed and implemented several years ago - the TSWV and Thrips Forecasting Tool for Tobacco. This tool is widely used by tobacco growers and crop consultants to inform decisions regarding thrips and tomato spotted wilt(TSW) management. Because the models underlying this tooldo not account for the effects of prolonged periods of high plant susceptibillity to TSWthat are associated with delayed plant growth, the effectiveness of this tool is compromise when temperatures areunusuallylowfollowing transplanting. To address this problem, we collected data on tobacco plant growth following transplanting over multiple plant dates at each of 4 locations in North Carolina.Plant growth and daily weather data were obtained for each site between transplanting and flowering, when mature plant resistance to TSWis fully developed. These data will be used to develop a plant growth and TSWV susceptibility model thatwill be integrated into the on-line TSWV andThrips Forecasting Tool for Tobacco, to improve predictions In othercollaborative efforts with plant pathologists at University of Georgia, we applied experimantal and survey data to model the relationship between weather, thrips populations and TSW risk in peanut. The resultingmodels were then applied to the established TSW management decision aid for Georgia (Peanut Rx)to demonstratethat addition of predictions of thetemporal occurrence of major thrips flights based on weather enhanced the reliability of the TSW risk management tool.

Publications

• Type: Journal Articles Status: Published Year Published: 2020 Citation: Chappell, T. M., Ward, R. V., DePolt, K. T., Roberts, P. M., Greene, J. K., & Kennedy, G.G. (2020). Cotton thrips infestation predictor: a practical tool for predicting tobacco thrips(Frankliniella fusca) infestation of cotton seedlings in the south-eastern United States. PEST MANAGEMENT SCIENCE. https://doi.org/10.1002/ps.5954
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Ruark-Seward, C. L., Bonville, B., Kennedy, G., & Rasmussen, D. A. (2020). Evolutionary dynamics of Tomato spotted wilt virus within and between alternate plant hosts and thrips. SCIENTIFIC REPORTS, 10(1). https://doi.org/10.1038/s41598-020-72691-3
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Damon A. D'Ambrosio, Kennedy, G. G., & Huseth, A. S. (2020). Feeding behavior of Frankliniella fusca on seedling cotton expressing Cry51Aa2.834_16 Bt toxin. PEST MANAGEMENT SCIENCE. https://doi.org/10.1002/ps.5825
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Damon A. D'Ambrosio, Kennedy, G. G., & Huseth, A. S. (2020). Frankliniella fusca and Frankliniella occidentalis response to thrips-active Cry51Aa2.834_16 Bt cotton with and without neonicotinoid seed treatment. CROP PROTECTION, 129. https://doi.org/10.1016/j.cropro.2019.105042 5). Linak, J. A., Jacobson, A. L., Sit, T. L., &
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Linak, J. A., Jacobson, A. L., Sit, T. L., & Kennedy, G. G. (2020). Relationships of virus titers and transmission rates among sympatric and allopatric virus isolates and thrips vectors support local adaptation. SCIENTIFIC REPORTS, 10(1). https://doi.org/10.1038/s41598-020-64507-1
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Kennedy, GG Huseth AS (2020). Pest pressure relates to similarity of crops and native plants. PNAS, 117 (47), 29260-29262
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Huseth, AS, D'Ambrosio, DA, Kennedy,GG (2020). Understanding the potential impact of continued seed treatment use for resistance management in Cry51Aa2.834_16 Bt cotton against Frankliniella fusca. PLoS one, 15(10), PMID:e0239910
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Huseth, AS, D'Ambrosio, DA, Yorke, BT, Head, GP, Kennedy,GG (2020). Novel mechanism of thrips suppression by Cry51Aa2.834_16 Bt toxin expression in cotton. Pest Management Science, 76(4), 1492-1499.