Source: RESEARCH FOUNDATION OF THE CITY UNIVERSITY OF NEW YORK submitted to NRP
ROTATION DISTANCE AND RESISTANCE MANAGEMENT IN COLORADO POTATO BEETLE: IS MOVEMENT A COST OF RESISTANCE?
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
NRI COMPETITIVE GRANT
Reporting Frequency
Annual
Accession No.
0214726
Grant No.
2008-35302-04496
Cumulative Award Amt.
$158,780.00
Proposal No.
2008-02395
Multistate No.
(N/A)
Project Start Date
Sep 1, 2008
Project End Date
Jul 31, 2011
Grant Year
2008
Program Code
[51.2A]- Arthropod and Nematode Biology and Management (A): Organismal and Population Biology
Recipient Organization
RESEARCH FOUNDATION OF THE CITY UNIVERSITY OF NEW YORK
230 W 41ST STREET FL 7
NEW YORK,NY 10036-7207
Performing Department
(N/A)
Non Technical Summary
Increasing pesticide use places an economic burden on growers and a health and environmental burden on growers and non-growers alike. Colorado potato beetles are notorious for evolving resistance to insecticides. When populations become resistant to insecticides growers use more frequent and more highly concentrated sprays, with higher economic and environmental costs, so managing the evolution of resistance is highly desirable. Resistance to insecticides often incurs costs to the insects themselves, which may be weaker in other ways. Colorado potato beetles resistant to imidacloprid lay fewer eggs, can't walk as fast, take longer to hatch, and have lower overwinter survival. If resistant beetles are less able to fly long distances and locate newly planted fields, that trade-off can be used to manage resistance evolution. This project measures whether resistance to two commonly used insecticides entails a cost to the insects in terms of movement, and at what spatial scale those costs are present. We will measure movement costs in the field, looking at resistance in spring-colonizing beetles at emergence and at increasing distances from the emergence site. We will carry out laboratory studies using a flight mill, a device where tethered beetles fly in circles, to see if resistant and susceptible beetles differ in their flight range, and we will measure whether beetles colonizing continuously planted fields are more resistant than those colonizing newly planted fields that were rotated away from potato the previous year. Rotated fields must attract beetles from longer distances and if there are movement costs they will attract less resistant beetles. The results of this study will be resistance management plants that identify the optimum distances for planting new potato fields from last year's potato fields that will reduce the resistance of colonists and reduce the amount of insecticide needed to control beetle populations. The results will also help manage resistance in other species for which resistance costs can be identified.
Animal Health Component
50%
Research Effort Categories
Basic
50%
Applied
50%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2113110108025%
2113110113025%
2113110115025%
2113110107025%
Knowledge Area
211 - Insects, Mites, and Other Arthropods Affecting Plants;

Subject Of Investigation
3110 - Insects;

Field Of Science
1130 - Entomology and acarology; 1070 - Ecology; 1080 - Genetics; 1150 - Toxicology;
Goals / Objectives
The goal is to use movement behavior to manage both insect damage and the evolution of resistance to insecticides in Colorado potato beetles. This project will determine whether it is possible to slow resistance evolution by increasing the distance between rotated fields and the previous year's crop, and if so, what that distance should be. This strategy will be effective if more resistant beetles are not able to walk or fly as far to colonize new fields. Movement costs will also aid the function of refuge crops, the primary means for slowing the evolution of resistance in transgenic insecticidal crops. We will measure the movement costs of resistance to both imidacloprid and spinosad, two of the most commonly used treatments against potato beetles, and use those costs to generate a resistance management plan describing optimal rotations of potato and insecticides, and optimal distances between rotated fields, to both manage beetle populations and maintain susceptibility to insecticide.
Project Methods
We will collect and assay emerging, flying and colonizing beetles at different distances from 50-400 meters from a central overwintering site for resistance to imidacloprid and spinosad. Adults are collected prior to exposure on any target field by trapping walkers directly at the overwintering site using drift fences, flyers at the overwintering site using harp traps and nets, and colonists at within fields using both drift fences and raised, isolated trap plants. We will test colonizing adults, and the subsequent summer generation, for resistance in continuously planted potato fields and in rotated fields with and without in-furrow treatment with imidacloprid. If reduced movement is a cost of resistance we will find that rotated fields are colonized by less resistant beetles. We will conduct a flight mill study of the flight capacity of CPB resistant and susceptible to imidacloprid and spinosad. We will compare the flight capability of lab reared offspring of field collected adults, and also carry out crosses and backcrosses to create genetically diverse families, which will be tested quantitatively for flight on the flight mill, and then for resistance using a knockdown time assay. Finally, we will extend an evolutionary simulation model of resistance and migration in refuge-based landscapes (landscapes consisting of treated and untreated potato, and non-potato matrix) to optimize treatment and spacing of refuges and rotated crops

Progress 09/01/08 to 08/31/09

Outputs
OUTPUTS: The objectives of this study were to compare imidacloprid resistance of flying and walking beetles emerging from overwintering sites, compare resistance of beetles colonizing potato fields rotated from other crops or replanted in potato, compare the resistance of untreated resistant and susceptible and hybrid beetles on a flight mill, and develop a model of resistance evolution with or without a movement cost of resistance. Activities: 426 Walking and 153 flying beetles were collected from a single overwintering site in eastern Long Island, assayed as adults using a range of concentrations of imidacloprid in acetone in 2008. In 2009 634 walking emergers and 190 flying emergers were collected from two overwintering sites in eastern long island and assayed for resistance. In 2008 852 adults were collected from three non-rotated fields, and 518 adults were collected from 3 rotated fields and assayed for imidacloprid resistance. In 2009 2181 colonists in 8 rotated fields, and 1785 colonizing adults to non-rotated fields were collected and assayed for resistance to imidacloprid. On PhD student, two MS students, and four undergraduate students participated in the data collection for this project. In addition, several hundred adults were collected at 50-400 meters from a central overwintering site on eastern Long Island and assayed for resistance. Events: Results were presented at the 2008 Entomological Society of America meeting in Reno, NV, the 2008 International Society for Behavioral Ecology Meeting in Ithaca NY, and the Eastern Branch of the Entomological Society of America meeting in 2009. PARTICIPANTS: Kathleen Schnaars, PhD student, Queens College and Graduate Center of CUNY, managed all the field collection and supervised undergraduate and post-graduate students and assistants in bioassay. Kit advanced to candidacy in the program, and presented posters at National and Eastern Branch Entomological Society of America meetings in 2008 and 2009. Karyn Collie, PhD student, Queens College and Graduate Center of CUNY, managed the lab and coordinated planting and support for bioassay and colony maintence during this project. This grant supported several MS and UG students who contributed to greenhouse maintenance, collection, and bioassay, and were also mentored (for course credit and not for pay) in independent projects supporting the objectives of this project or other studies of resistance costs or trade-offs: Katherine Paccione, Undergraduate and Masters student. Katherine worked in the lab on this project, also carrying out an independent study on fitness and incomplete resistance on treated and untreated plants. Fiorella Tapia-Ortiz, MS student, contributed to collection and bioassay John Cohen, UG student, contributed to collection and bioassay and conducted an independent study of olfactory sensitivity in resistant and susceptible beetles Simon Greenbaum, UG student, contributed to beetle culture and bioassay, and conducted independent study on differences between resistant and susceptible beetles on immune function of resistant and susceptible beetles Daniel Greenberg, Post-grad assistant, contributed to bioassays Mary Polsunas, non-student assistant, helped with collection and bioassay TARGET AUDIENCES: The target audiences for this project are potato growers, both conventional and organic, extension and university researchers who can pass along the results to growers they are working with. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
This project is ongoing, but our results were somewhat unexpected and pending the remaining objectives will lead to a change in knowledge of the role of crop rotation on resistance management. This project is testing the hypothesis that medium to long distance movement (movement between fields or movement within large fields) is reduced in highly resistant beetles. We have probably disproved that hypothesis in field populations. Flying beetles were consistently (though not always significantly) more resistant than walking beetles in each of the three collections of walking and flying emergers. In 2008, colonists to rotated fields were significantly more resistant than colonists to non-rotated fields, and in 2009, there was no difference in resistance between rotated and non-rotated fields. The results thus far show that, at least in moderately to highly resistant populations of beetles, all or most of whom are exposed to imidacloprid, the most resistant beetles move just as far or farther than less resistant beetles. It is possible that exposure to insecticide causes this result, which will make this year's flight mill assays on untreated beetles that much more important, and we will also expand sampling to two organic farms on Long Island as well. The consequence of this result is that in areas with uniform treatment with neonicotinoid insecticides growers should not expect rotated fields to be less resistant to insecticides, and the need to manage resistance, preferably by rotating insecticide treatment away from neonicotinoids in rotated fields, is more important than previously thought. For the second year of the project, simulation models of resistance evolution with movement benefits as well as costs of resistance will be further developed, resistance of flying walkers and emergers to imidacloprid and spinosad will be replicated, and organic (untreated with neonicotinoid) fields will be targeted for sampling.

Publications

  • No publications reported this period