Pheromone Formulations for Insect Control in Agriculture - American

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Pheromone Formulations for Insect Control in Agriculture 1

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Janice Gillespie , Scott Herbig , and Ron Beyerinck 1

Downloaded by UNIV OF PITTSBURGH on May 3, 2015 | http://pubs.acs.org Publication Date: May 5, 1995 | doi: 10.1021/bk-1995-0595.ch014

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Consep, Inc., 213 S.W. Columbia Street, Bend, OR 97702-1013 Bend Research, Inc., 64550 Research Road, Bend, OR 97701-8599

Pheromones are useful for insect control in Integrated Pest Management (IPM) programs. Most of the semiochemicals that have been commercialized are sex pheromones for pests of cotton, specialty row crops, and orchard crops. Two major classes of formulations have been registered: 1) hand-applied dispensers, and 2) sprayable formulations. The hand-applied dispensers typically provide long durations of efficacy but can be inconvenient to apply to large acreages. Sprayable formulations can be applied quickly and to large areas using conventional ground or aerial equipment, but these formulations typically have shorter durations of efficacy (weeks versus months). Efficacy is the primary goal in the design of all pheromone products. Optimizing formulations to minimize cost and making their use economically compelling, rather than just economically competitive with conventional insecticides, is the key to acceptance and use of pheromone-based products.

Many products containing insect pheromones have been introduced in recent years for control of insect pests in agricultural, household and, to a lesser extent, forestry applications. The active ingredients (AI) of most of these products are the sex pheromones of the Lepidoptera (moths, skippers, and butterflies). Sex pheromones are biological chemicals emitted by an individual insect to attract a receiving, conspecific individual of the opposite sex for mating. Products based on alarm pheromones of the Homoptera (aphids and their relatives) and aggregation pheromones of Coleoptera (beetles)—as well as naturally occurring chemicals that function as insect attractants—also have been developed and/or commercialized in these markets. 0097-6156/95/0595-0208$12.00/0 © 1995 American Chemical Society

In Biorational Pest Control Agents; Hall, F., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1995.

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Major uses of pheromone-based products developed since the early 1970s include insect survey, detection, and monitoring in Integrated Pest Management (IPM) programs, insect eradication, and insect control.


Pheromone Products for Survey, Detection, Eradication, and Monitoring State and federal agencies are using pheromone-baited traps for the survey, detection, and eradication of exotic pests. Applications include the detection of Japanese beetles (Popillia japonica Newman) in certain western states, and the identification of locations requiring insecticide treatment in areawide eradication programs. For example, an eradication program in the southeastern United States targets boll weevil (Anthonomus grandis Boheman) (1) and an eradication program in the southwestern United States targets pink bollworm (Pectinophora gossypiella Saunders). Products for monitoring the presence, growth, and development of damaging insect populations are available for major insect pests in row, vegetable, and tree fruit and nut crops. Often the monitoring products are used to establish the time of emergence of the overwintered pests (Biofix, the time that the first moth of the season is captured in pheromone-baited traps) and to initiate heat-unit-based population models useful for accurately targeting insecticide applications. Products in the household pest-control market assist homeowners in identifying home and garden pests, in removing nuisance pests such as yellowjackets, and in planning appropriate control procedures for garden pests. These products can also be used by the structural pest-control industry to locate infestations in the home environment. Products for Control of Pests Certain descriptive terms are useful to classify the principal mode of action of commercial pheromone products for control of insect and mite pests. These are 1) mating disruptants, 2) attracticides, 3) bioirritants, and 4) deterrents. Mating disrupants, which act by permeating the crop environment with sex pheromone to prevent reproduction and reduce infestations, have been and continue to be a primary target of commercial R & D efforts (2,3). Mating-disruptants are designed to flood the crop environment with a synthetic replica of the sex pheromone, thereby preventing the sexes from locating each other and mating. Reduced reproduction rates prevent or delay growth of the population to the economic threshold and eliminate or significantly reduce the need to use conventional insecticides. Some attracticides also control insect populations through disruption of mating (4). In these products, a small amount of a conventional insecticide is added to the pheromone product (as a tank mix) to kill moths seeking a mate (5). The addition of insecticide enhances the mating-disruption system by removing "sexually active" individuals from the population. Pheromones that attract pests to a substrate impregnated with insecticide (e.g., Plato Industries' Boll Weevil Attract And Control Tube) are an example of an attracticide product that does not involve mating


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disruption (6). This type of product is designed to kill all pests attracted when they feed or otherwise contact the substrate impregnated with conventional insecticide. The term "bioirritant" describes certain tank-mix applications that contain low levels of sex pheromones (below effective disruption levels) and conventional insecticides. The mode of action of bioirritants is to increase contact between moths excited in the presence of the pheromone and foliar residues of the insecticide. A deterrent mode of action may best describe certain pheromones—e.g., trans-P-farnesene, an alarm pheromone of aphids—wherein conspecific individuals respond to the pheromone by evacuating the substrate. Products based on these pheromones may prevent colonization of a host crop and subsequent disease transmission and crop loss (7). Problems in Early Commercialization Efforts (1970s and 1980s) Many problems became apparent in early efforts to commercialize pheromone-based products during the 1970s and 1980s, some of which are listed below: • special application equipment required, • short field life of products, • limited knowledge of IPM, • introduction of synthetic pyrethroids, • poor efficacy related to low application rates, and • limited R & D for new uses. The first commercial pheromone products were registered to control the pink bollworm in cotton. Brooks et al. in 1979 (8) and Kydonieus et al. in 1981 (P) described two controlled-release pheromone products for pink bollworm and the specialized equipment required to apply them. These early formulations were efficacious for 1 to 3 weeks, depending on temperatures and development of crop canopy to hold the hollow-fiber and laminated-flake products, respectively. Products with longer durations were needed for pests of tree fruit and nut crops, where the overwintered generation may emerge for up to 90 days after the first moth emerges. Licensed Pest Control Advisors (PCAs) responsible for crop protection often had a sketchy understanding of integrated pest control and limited knowledge of practical strategies for implementation of integrated programs in the field. Although they were expensive, synthetic pyrethroids competed with nontoxic control programs in the mid-1970s since pyrethroids promised insecticidal solutions that offered lower mammalian toxicity for hard-to-control pests. The efficacy of pyrethroid products initially delayed the impetus for biorational alternatives to all conventional insecticides. Economic considerations also affected development of pheromone-based products. Because only small quantities of pheromones were needed, their cost was high—as is true with other low-volume specialty chemicals. Due to the high cost of pheromones, their application rates were kept low to keep the costs of pheromonebased pest-control products competitive with those of conventional toxic insecticides. In some cases, these low application rates resulted in insufficient efficacy. Finally, exploratory R & D was severely limited by regulatory constraints on



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test-plot size (limited to 10 acres before an Experimental Use Permit is required) and crop-purchase requirements (when regulatory approval is not obtained). In the mid-1980s, Flint et al. and Rice et al. reported on field trials of manually applied polyethylene tube dispensers designed to last several insect generations (10,11). These dispensers were applied at high rates of active ingredient (e.g., 75 g Al/ha). Sprayable bead and granule products that can be applied using conventional ground and aerial dispensing equipment also became available in the mid-1980s. These products are repeatedly applied at high rates (20 to 25 g Al/ha) at appropriate intervals to provide control through mating disruption. Many product forms are available today, and other efficacious forms will become available in coming years. The manually applied dispensers typically provide long durations of efficacy but can be inconvenient to apply to large acreages. Sprayable formulations can be applied quickly and to large areas using conventional ground and aerial equipment but typically show shorter durations of efficacy (weeks versus months) and are affected more by weather conditions (e.g., rain, U V radiation). Regulatory Authority The pheromone-based products described above for detection and/or monitoring are exempt from registration requirements mandated by the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA), but not from regulation by the Environmental Protection Agency (EPA). Pheromone-based products used for control of insect pests are now classified as biorational pesticides and are registered as such by the EPA. Registration testing requirements are significantly reduced for biorational pesticides, as compared with conventional insecticides, and the review process required before registration is significantly shorter (typically 12 months). Rules enacted between December 1993 and July 1994 control evaluation of these products and have provided significant regulatory relief to the biorational pesticide industry. These rules include 1) generic exemptions from the requirement of a tolerance for inert ingredients in manually applied dispensers and for pheromones formulated in manually applied dispensers, and 2) a provision allowing evaluation of these products on up to 250 acres without an Experimental Use Permit. Current Directions in Product Development Formulation optimization to maximize field efficacy and minimize cost are imperative to increase product use in IPM programs, especially because implementation of these programs often necessitates more-thorough field monitoring by the PCA. Also key to increased on-farm use (to meet President Clinton's policy goal that 70% of U.S. farm acreage will be under I P M by 2000) is improved pestscouting techniques to facilitate the shift from calendar-based spray programs to IPM programs. A legitimate goal of the biorational pesticide industry is to make the use of pheromone-based products economically compelling rather than just economically competitive with conventional insecticides.


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Literature Cited 1. 2. 3. 4. 5.


6.

RECEIVED

7.

8.

9.

10. 11.

Ridgway, R.L., in Proc. Beltwide Cotton Prod. Res. Conf., National Cotton Council, Raleigh, NC, 1978, 108-109. Beroza, M., Agric. Chem., 1960, 15, 37. Babson, A.L., Sci., 1963, 142, 447. Conlee, J., and Staten, R.T., U.S. Patent No. 4,671,010. Butler, G.W., Henneberry, T.J., and Barker, R.J., USDA ARS ARM W-35, 1983, 1-13. McKibben, G.H., Smith, J.W., and McGovern, W.L., J. Entomol. Sci., 1990, 25, 581-586. Briggs, G.G., Dawson, G.W., Gibson, R.W., and Pickett, J.A., in Proceedings 5th International Congress of Pesticide Chemistry, Miyamoto, J. and Kearney, P.C. Eds.; Pergamon, Oxford, 1983, pp. 117-122. Brooks, T.W., Doane, C.C., and Staten, R.T., in Chemical Ecology: Odour Communication in Animals, Ritter, F.J., Ed.; Elsevier, New York, NY, 1979, pp. 375-388. Kydonieus, A.F., Gillespie, J.M., Barry, M.W., Welch, J., Henneberry, T.J., and Leonhardt, B.A., in American Chemical Society Symposium Series 190. Insect Pheromone Technology: Chemistry and Applications, Leonhardt, B.A., and Beroza, M., Eds.; 1981. Flint, H.M., Merkle, J.R., and Yamamoto, A., J. Econ. Entomol., 1985, 78, 1431-1436. Rice, R.E., and Kirsch, P., in Behavior-Modifying Chemicals for Insect Management—Applications of Pheromones and Other Attractants, Ridgway, R.L., Silverstein, R.M., and Inscoe, M.N., Eds.; Marcel-Dekker, New York, NY, 1990, pp. 193-211. January 12, 1995


Pheromone Formulations for Insect Control in Agriculture - American

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