Source: UNIVERSITY OF MAINE submitted to
GEOGRAPHIC VARIATION IN THE COLORADO POTATO BEETLE RESISTANCE TO IMIDACLOPRID
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
TERMINATED
Funding Source
NRI COMPETITIVE GRANT
Reporting Frequency
Annual
Accession No.
0219891
Grant No.
2009-35505-06004
Project No.
ME02008-02365
Proposal No.
2008-02365
Multistate No.
(N/A)
Program Code
51.2A
Project Start Date
Sep 1, 2009
Project End Date
Aug 31, 2012
Grant Year
2009
Project Director
Alyokhin, A. V.
Recipient Organization
UNIVERSITY OF MAINE
(N/A)
ORONO,ME 04469
Performing Department
School of Biology & Ecology
Non Technical Summary
Colorado potato beetle is the most important insect defoliator of potatoes and is notorious for its ability to develop resistance to a wide variety of chemicals. Successful potato production in large part depends on grower ability to control Colorado potato beetle. Imidacloprid and, to a smaller degree, other neonicotionids serve as a foundation of beetle control on commercial farms. These insecticides combine relatively low mammalian toxicity, high efficiency against target pests, and affordable price. Loss of their availability for controlling the Colorado potato beetle is likely to be a serious problem even when alternative chemistries still suppress resistant populations. First, development of new insecticides is increasingly expensive, which affects their market price paid by growers. Secondly, available alternatives may be less convenient and more environmentally damaging than the failed insecticides they have to replace. Third, a threat of insecticide failure due to resistance development increases the already high real and perceived risks of potato farming. Recommendations on resistance management are commonly developed based on studies of as little as one resistant strain, often selected under laboratory conditions. Although such an approach is often valid, resistance mechanisms may be diverse even within a relatively limited geographic area. Therefore, information obtained in one location will not necessarily apply to other locations where resistance becomes a problem. In other cases, recommendations are made based on mathematic models. Again, this could be a valuable approach given that an appropriate model is selected. However, model assumptions cannot be taken for granted and should be verified using experimental techniques. The long-term goal of this research is to develop a management plan for preventing imidacloprid resistance in the Colorado potato beetle populations that can be customized for effective use in a variety of geographic locations. Most Colorado potato beetle populations are still highly susceptible to imidacloprid and other neonicotinoids. Taking a proactive approach at this point in time will help preserving efficiency of this class of chemicals. Development of effective plans to manage imidacloprid resistance would greatly benefit a wide variety of stakeholders. However, it will not be possible without a thorough understanding of the system in question, including its physiological, ecological, genetic, and behavioral aspects. All scientists involved in the project have been investigating various aspects of imidacloprid resistance in the Colorado potato beetle for the past eight years. In the proposed study, we suggest combining our efforts to ?put different pieces of a big puzzle together? and obtain a comprehensive understanding of this phenomenon. This would allow developing a resistance management plan that will be based on a solid scientific foundation and apply to variety of potato-growing areas.
Animal Health Component
(N/A)
Research Effort Categories
Basic
25%
Applied
75%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2111310102040%
2111310107035%
2111310108025%
Knowledge Area
211 - Insects, Mites, and Other Arthropods Affecting Plants;

Subject Of Investigation
1310 - Potato;

Field Of Science
1070 - Ecology; 1080 - Genetics; 1020 - Physiology;
Goals / Objectives
The long-term goal of this research is to develop a management plan for preventing imidacloprid resistance in the Colorado potato beetle populations that can be customized for effective use in a variety of geographic locations. We hypothesize that mechanisms of imidacloprid resistance differ among the affected populations. As a result, any successful approach to resistance management should be based on a good understanding of the biology of individual targeted populations. To test our null hypothesis, we propose quantifying variation among beetle populations that are known to be resistant to imidacloprid. More specifically, for each population we will: (1) Quantify levels of resistance; (2) Determine fitness costs of resistant alleles; (3) Determine modes of inheritance of insecticide resistance and its fitness costs; and (4) Identify physiological mechanisms of resistance. Successful completion of this project will result in manuscript published in peer-reviewed journals, presentations at scientific conferences and grower meetings, and practical recommendations on insecticide resistance management developed for commercial growers and Cooperative Extension personnel.
Project Methods
Six populations that are known to be resistant to imidacloprid and another six populations that are known to be susceptible to imidacloprid will be used for this study. The populations will originate from Maine, Long Island (New York), and Michigan. Resistance levels for each population will be determined using laboratory bioassays. Fitness costs of resistant alleles will be determined by comparing fecundity, mortality, egg-to-adult survivorship, time of development, intrinsic rate of population increase, overwintering survivorship, and flight propensity of resistant and susceptible field-collected beetles in a series of laboratory experiments. Inheritance of resistance will be determined by measuring the resistance of progeny of crosses within and between a laboratory susceptible colony (see above) and the various resistant populations. Heritability and correlations between resistance and fecundity, fertility, and development time within populations will be analyzed using a half-sib design. Finally, dominance of fitness will be estimated in field cages. The rate of excretion and metabolism of 14C-imidacloprid (labeled at the imidazolidine ring) in resistant populations will be identified and compared with the susceptible populations. At least one cross between resistant and susceptible insects also will be tested. This will include measuring imidacloprid-induced mortality with and without metabolic synergists such as piperonyl butoxide, an inhibitor of oxidases, PBO and another inhibitor of esterases, DEF. 14C-imidacloprid will be applied via oral bioassays to adults and third early instar larvae. In addition, in vitro biochemical tests will determine the microsomal activity to transform 14C -imidacloprid and other substrates. We expect to find variation in resistance mechanisms, dominance, and costs, but the project has value whether or not variation is present. This study will provide the scientific framework for developing a resistance management plan that can be customized to different Colorado potato beetle populations.

Progress 09/01/09 to 08/31/12

Outputs
OUTPUTS: Mechanisms of resistance to a commonly used insecticide imidacloprid were determined for several geographically isolated Colorado potato beetle populations. Life-history traits relevant for resistance management were quantified for resistant and susceptible beetles. Applicability of resistance management plans across potato-growing areas has been demonstrated. Information generated by this project was disseminated among the target audiences: Alyokhin, A. and L. Miller. 2012. Movement of adult Colorado potato beetles following exposure to imidacloprid. Entomological Society of America Annual Meeting, Knoxville, TN. Chen, J., Alyokhin, A., D. Mota-Sanchez, M. Baker, and M. Whalon. 2012. Interactions between thermal stress and insecticide resistance in geographically isolated Colorado potato beetle strains. Entomological Society of America Annual Meeting, Knoxville, TN. Alyokhin, A., D. Mota-Sanchez, M. Baker, J. Chen, and M. Whalon. 2012. Geographic variation among Colorado potato beetle populations and its implications for managing insecticide resistance. XXIV International Congress of Entomology, Daegu, South Korea. Chen, J., A. Alyokhin, D. Mota-Sanchez, M. Baker, and M.E. Whalon. 2012. Geographic variation in growth potential of Colorado potato beetle populations. Annual Meeting of the Potato Association of America, Denver, CO. Chen, J., A. Alyokhin, D. Mota-Sanchez, M. Baker, and M.E. Whalon. 2011. Variation in life history parameters in geographically isolated populations of the Colorado potato beetle. Entomological Society of America Annual Meeting, Reno, NV. Mota-Sanchez, D., M.E Whalon, A. Alyokhin, M. Baker, and R.M. Hollingworth. 2011. Geographic variation in the Colorado potato beetle resistance to imidacloprid. ESA Annual Meeting, Reno, NV. Alyokhin, A., M. Patterson, G. Dively, and D. Rogers. 2011. Managing Colorado potato beetle resistance to imidacloprid: From theory to practice. Northeast Potato Technology Forum, Fredericton, New Brunswick, Canada. Alyokhin, A., G. Dively, and D. Rogers. 2010. Performance of an insecticide resistance management plan on a commercial potato farm. Entomological Society of America Annual Meeting, San Diego, CA. Mota-Sanchez, D., M. Baker, A. Alyokhin, M.E. Whalon, and M. Otto. 2010. Mechanism of resistance of Colorado potato beetles to imidacloprid. WERA-060 Meeting, Nov. 11-12, 2010 Kellogg Center, MSU East Lansing, MI. Alyokhin, A. 2012. Environmental implications of insecticide resistance. Heart of Maine's 10th Annual Soils Quality Conference, Bangor, ME. Alyokhin, A. 2012. Insecticide resistance and sustainability of chemical control. In-Service Training for Agricultural Service Providers, Portsmouth, NH. Alyokhin, A. 2011. Life beyond neonicotinoids. 26th Annual Maine Potato Conference, Caribou, ME. Alyokhin, A. 2011. Why Colorado potato beetle is so hard to control: a lesson in resistance. 70th Maine Agricultural Trades Show, Augusta, Maine. Alyokhin, A. 2010. Is there life beyond neonicotinoids 2010 Potato Pest Management Conference, Presque Isle, ME. Alyokhin, A. and B. Caldwell. 2010. Getting the most out of organic pesticides. Farmer to Farmer Conference, Northport, ME. PARTICIPANTS: PIs: Alyokhin, Andrei (University of Maine), David Mota-Sanchez (Michigan State University), Mitchell Baker (City University of New York), Mark Whalon (Michigan State University). Graduate students: Jie Chen (University of Maine), Kit Schnaars-Uvino, Karyn Collie (City University of New York). Undergraduate students: Svenson Pulsifer, Cody Martel, Lindsey Miller, Paul Ohno, Evan Toth, Amanda Bailey (University of Maine), Eric Copeli, Kazi Hossain, Kristina Zabierek, Annick Fremont, Vanessa Accosta (City University of New York). TARGET AUDIENCES: Target audiences: commercial potato growers, crop consultants, extension personnel, scientists. Efforts: sharing collected information with other scientists, training graduate and undergraduate students through hands-on participation in research in our laboratories. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
The main impacts are improved understanding of the mechanisms of imidacloprid resistance in the Colorado potato beetle, and obtaining quantitative information on variation in relative fitness among geographically isolated populations of resistant and susceptible beetles. We discovered that P450s were involved in the mechanism of resistance to imidacloprid in both adults and larvae regardless of their geographic origin. However, the levels of PBO synergism were lower in larvae than in adults. This might mean existence of an additional non-P450 resistance mechanism in larvae. The most resistant population was 72-fold resistant compared to the most susceptible population based on the results of topical larval bioassays. Resistance in all tested populations was closer to recessive than to additive. There was variation in fitness parameters among the strains. Insecticide resistant strains had lower number of eggs per egg mass. However, we did not detect any other fitness costs of imidacloprid resistance. Fitness of the susceptible laboratory NJ strain was generally low, possibly because of inbreeding and selection for adaptation to laboratory conditions. Interestingly, the sex ratio was female-biased for the MI strain. To the best of our knowledge, this is the first such record for the Colorado potato beetle. Implementing an insecticide resistance management plan on two commercial farms in southern Maine resulted in significant reduction in resistance levels in beetle populations. Because imidacloprid resistance appears to have a similar mechanism in all tested populations, it might be possible to develop a unified resistance management approach applicable to a variety of areas.

Publications

  • Alyokhin, A., M. Udalov, and G. Benkovskaya. 2013. The Colorado potato beetle. In: Giordanengo, P., C. Vincent, and A. Alyokhin [editors]. Insect Pests of Potato: Global Perspectives on Biology and Management. Academic Press, Oxford, UK. Pp. 11-29.
  • Alyokhin, A., Y. H. Chen, M. Udalov, G. Benkovskaya, and L. Lindstrom. 2013. Evolutionary considerations in potato pest management. In: Giordanengo, P., C. Vincent, and A. Alyokhin [editors]. Insect Pests of Potato: Global Perspectives on Biology and Management. Academic Press, Oxford, UK. Pp. 543-571.


Progress 09/01/10 to 08/31/11

Outputs
OUTPUTS: Following our previous year's discovery that imidacloprid resistance in Colorado potato beetle adults is due mainly to monooxygenases activity, we tested a hypothesis that a similar mechanism exists in larvae. We also completed a series of common-garden experiments comparing life-history traits among geographically isolated populations of resistant and susceptible beetles. Information generated by this project was disseminated among the target audience through extension presentations, an article in a widely circulated potato newsletter, and an interview with The Grower magazine. Printed factsheet on managing insecticide resistance in the Colorado potato beetle was distributed among potato and vegetable growers attending several extension conferences. The following professional presentations were delivered: Alyokhin, A., M. Patterson, G. Dively, and D. Rogers. 2011. Managing Colorado potato beetle resistance to imidacloprid: From theory to practice. Northeast Potato Technology Forum, Fredericton, New Brunswick, Canada. Alyokhin, A., G. Dively, and D. Rogers. 2010. Performance of an insecticide resistance management plan on a commercial potato farm. Entomological Society of America Annual Meeting, San Diego, CA. [Data from the current project were integrated with the data from an earlier study] The following extension presentations were delivered: Alyokhin, A. 2011. Life beyond neonicotinoids. 26th Annual Maine Potato Conference, Caribou, ME. Alyokhin, A. 2011. Why Colorado potato beetle is so hard to control: a lesson in resistance. 70th Maine Agricultural Trades Show, Augusta, Maine. Alyokhin, A. 2010. Is there life beyond neonicotinoids 2010 Potato Pest Management Conference, Presque Isle, ME. Alyokhin, A. and B. Caldwell. 2010. Getting the most out of organic pesticides. Farmer to Farmer Conference, Northport, ME. [Data from the current project were used to set a comparison between a conventional and an organic production system] PARTICIPANTS: PIs: Alyokhin, Andrei (University of Maine), David Mota-Sanchez (Michigan State University), Mitchell Baker (City University of New York), Mark Whalon (Michigan State University). Graduate students: Jie Chen (University of Maine), Kit Schnaars-Uvino, Karyn Collie (City University of New York). Undergraduate students: Lindsey Miller, Paul Ohno, Evan Toth (University of Maine) TARGET AUDIENCES: Commercial potato growers, crop consultants, extension personnel, scientists. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
At this stage, the main impacts are improved understanding of the mechanisms of imidacloprid resistance in the Colorado potato beetle, and obtaining quantitative information on variation in relative fitness among geographically isolated populations of resistant and susceptible beetles. So far, we discovered that P450s were involved in the mechanism of resistance to imidacloprid in both adults and larvae regardless of their geographic origin. However, the levels of PBO synergism were lower in larvae than in adults. This might mean existence of an additional non-P450 resistance mechanism in larvae. There was variation in fitness parameters among the strains. Fitness of the susceptible laboratory NJ strain was generally low, possibly because of inbreeding and selection for adaptation to laboratory conditions. Interestingly, the sex ratio was female-biased for the MI strain. To the best of our knowledge, this is the first such record for the Colorado potato beetle. The observed variation in fitness parameters among the strains should be taken into consideration when making comparisons under common conditions in the laboratory.

Publications

  • Alyokhin, A. 2011. Imidacloprid resistance in the Colorado potato beetle: Another turn of the pesticide treadmill. Spudlines 49(2): 7-8.


Progress 09/01/09 to 08/31/10

Outputs
OUTPUTS: Data on levels of resistance, its inheritance, and in vivo metabolism and excretion of imidacloprid have been compiled for several geographically isolated populations and subjected to preliminary statistical analyses. Results were presented to the scientific audience: Mota-Sanchez, D., M. Baker, A. Alyokhin, M.E. Whalon, and M. Otto. 2010. Mechanism of resistance of Colorado potato beetles to imidacloprid. WERA-060 Meeting, Nov. 11-12, 2010 Kellogg Center, MSU East Lansing, MI. PARTICIPANTS: PIs: Alyokhin, Andrei (University of Maine), David Mota-Sanchez (Michigan State University), Mitchell Baker (City University of New York), Mark Whalon (Michigan State University). Graduate students: Jie Chen (University of Maine), Kit Schnaars-Uvino, Karyn Collie (City University of New York). Undergraduate students: Svenson Pulsifer, Cody Martel, Lindsey Miller (University of Maine), Eric Copeli, Kazi Hossain, Kristina Zabierek, Annick Fremont, Vanessa Accosta (City University of New York). TARGET AUDIENCES: Target audiences: commercial potato growers, crop consultants, extension personnel, scientists. Efforts: sharing collected information with other scientists, training graduate and undergraduate students through hands-on participation in research in our laboratories. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Resistance levels for each population were determined using laboratory bioassays. Inheritance of resistance was determined by measuring the resistance of progeny of crosses within and between a laboratory susceptible colony and the various resistant populations. Fitness costs of resistant alleles are currently being determined by comparing fecundity, mortality, egg-to-adult survivorship, time of development, intrinsic rate of population increase, overwintering survivorship, and flight propensity of resistant and susceptible field-collected beetles in a series of laboratory experiments. The rate of excretion and metabolism of 14C-imidacloprid (labeled at the imidazolidine ring) in resistant populations was identified and compared with the susceptible populations. The most resistant population was 72-fold resistant compared to the most susceptible population based on the results of topical larval bioassays. Resistance in all tested populations was closer to recessive than to additive. For the Maine population, this is different from the results of the 2001 assay, when resistance was closer to fully additive and slightly dominant. It is possible that the dominance decreased because of decreased selection pressure following growers in the affected area switching to using different chemicals. Resistant beetles from all populations treated with 14C-imidacloprid metabolized more compound than susceptible beetles, with rates of metabolism correlated with the levels of resistance. Monooxigenase inhibitor (PBO) suppressed imidacloprid metabolism, with the effect being stronger in the susceptible populations. This suggests esterase-dependent resistance mechanism. At this point in our investigations, imidacloprid resistance appears to have a similar mechanism in all tested populations, despite geographic variation in its strength. As a result, it might be possible to develop a unified resistance management approach applicable to a variety of areas.

Publications

  • No publications reported this period