Synthetic Host Volatiles Increase Efficacy of Trap Cropping for Management of Colorado Potato Beetle, Leptinotarsa Decemlineata (Say)
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University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln U.S. Department of Agriculture: Agricultural Publications from USDA-ARS / UNL Faculty Research Service, Lincoln, Nebraska 2005 Synthetic host volatiles increase efficacy of aptr cropping for management of Colorado potato beetle, Leptinotarsa decemlineata (Say) J. W. Martel University of Maine A. R. Alford University of Maine, [email protected] J. C. Dickens USDA-ARS Follow this and additional works at: https://digitalcommons.unl.edu/usdaarsfacpub Martel, J. W.; Alford, A. R.; and Dickens, J. C., "Synthetic host volatiles increase efficacy of aptr cropping for management of Colorado potato beetle, Leptinotarsa decemlineata (Say)" (2005). Publications from USDA-ARS / UNL Faculty. 1437. https://digitalcommons.unl.edu/usdaarsfacpub/1437 This Article is brought to you for free and open access by the U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Publications from USDA-ARS / UNL Faculty by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Agricultural and Forest Entomology (2005) 7, 79–86 Synthetic host volatiles increase efficacy of trap cropping for management of Colorado potato beetle, Leptinotarsa decemlineata (Say) J. W. Martel, A. R. Alford and J. C. Dickens* Department of Biological Sciences, University of Maine, Orono, ME 04469, U.S.A. and *USDA-ARS, Henry A. Wallace Beltsville Agricultural Research Center, Plant Sciences Institute, Chemicals Affecting Insect Behaviour Laboratory, Beltsville, MD 20705, U.S.A. Abstract 1 The attractiveness of pitfall traps baited with a synthetic host volatile attractant to colonizing adult Colorado potato beetle, Leptinotarsa decemlineata (Say) was evaluated in a field setting. 2 Significantly more postdiapause, colonizing adult L. decemlineata were captured in baited than unbaited pitfall traps. 3The potential for this synthetic kairomone to enhance the efficacy of trap cropping as a management tool was evaluated by comparing conventionally managed plots with like-sized plots bordered by either attractant-treated trap crop or untreated trap crop. 4 More postdiapause, colonizing adults, egg masses and small larvae were present in attractant-treated trap crops than in untreated trap crops. 5 There were no significant differences in egg mass and small larvae densities between plots bordered by attractant-treated trap crops and conventionally managed plots, but there were significantly fewer large larvae and adult beetles in conventionally managed plots. 6 Plant canopy area of conventionally managed plots was significantly greater than in plots bordered by either type of trap crop. 7 Yields for conventionally managed plots and plots bordered by attractant- treated trap crops did not differ, and less insecticide (44%) was applied to plots bordered by attractant-treated trap crops. Keywords Attractant, kairomone, Colorado potato beetle, plant volatiles, semiochemicals. Introduction delta-endotoxin in the laboratory (Whalon et al., 1993; Rahardja & Whalon, 1995). Increased public concern The Colorado potato beetle, Leptinotarsa decemlineata regarding the long-term effects of conventional insecticide (Say), is considered one of the most destructive insect use on human and environmental health has made it neces- pests of cultivated potato, Solanum tuberosum L., in North sary to develop alternative management strategies that America and Europe. It is of particular concern because it reduce the environmental impact of agricultural pest man- has developed resistance to a wide variety of conventional agement and decrease this pest’s capacity for development insecticides (Forgash, 1985; Boiteau, 1988; Hare, 1990; of resistance to chemical controls (Casagrande, 1987; Hare, Ioannidis et al., 1991; French et al., 1992; Olkowski et al., 1990; Shani, 1991; Smart et al., 1994; Ioriatti & Bouvier, 1992; Kennedy & French, 1994; Stewart et al., 1997), as well 2000). as Bacillus thuringiensis subspecies tenebrionis CryIIIA Trap crops are plantings grown for the purpose of draw- ing insect pest populations away from economic regions of production systems where they may be effectively managed Correspondence: A. R. Alford. Tel: þ1 207 581 2964; fax: and reduced before causing economic damage. By manip- þ1 207 581 2969; e-mail: [email protected] ulating spatial and temporal aspects of a crop ecosystem, # 2005 The Royal Entomological Society 80 J. W. Martel et al. invading pest populations can be aggregated in trap Materials and methods crop regions and densities reduced with well-timed, highly selective insecticide application (Hokkanen, 1991). If effect- Pitfall trap study ive larval control is achieved in the first generation, damage This study was initiated before plant emergence and from subsequent L. decemlineata generations could be conducted from 5 June to 20 June 2000 in two potato fields minimal (Wyman, 1995). (0.30 and 0.10 ha, respectively) at the University of Maine Early planted potato trap cropping, used to aggregate Agricultural and Forest Experiment Station Rogers Farm, L. decemlineata for chemical management, has been Stillwater, Maine. practiced in the former Soviet republic of Belarus from Twenty-two pitfall traps were evenly spaced at 10-m 1957 onward (Dorozhkin et al., 1975). Trap crops intervals around the perimeter of the 0.30 ha field, and planted 5–10 days before main crops (sized 5% of main 20 traps were evenly spaced at 10-m intervals around the crop area) were recommended for L. decemlineata man- perimeter of the 0.10 ha field to test whether the synthetic agement in Bulgaria (Bozhkov, 1985). Chausov (1976) volatile attractant blend attracted postdiapause, coloniz- reported that 2–5 ha of trap crop provided sufficient ing adult L. decemlineata. In both fields, odd numbered protection for 200–500 ha of main economic crop in traps were baited and even numbered traps served as Russia, such that the number of insecticide applications controls. Insects were collected from pitfall traps daily in the main crop was reduced from two to one per between 12.00 and 14.00 h (EST) for the duration of the growing season. experiment. The attractiveness of trap crop plantings to insect pests Traps consisted of 20.3-cm diameter plastic flower pots might be further enhanced by application of attractive semio- dug into the soil. Pot rims lay flush with ground level. One chemicals, such as insect pheromones or plant kairomones 0.61-m iron rod was driven 15.2 cm through the bottom of (Hardee, 1982; Metcalf, 1985). Because L. decemlineata is each pot to secure it in place, and green plastic foliage attracted to volatiles emanating from host plants in labora- painted with John Deere YellowTM spray paint (Sherwin- tory bioassays (McIndoo, 1926; Schanz, 1953; DeWilde, Williams Company, Cleveland, Ohio) was attached to the 1976; Visser & Ave´ , 1978; Bolter et al., 1997; Landolt upper portion of the rod to provide an attractive plant et al., 1999), it is possible that synthetic blends of model. Zehnder & Speese (1987), Van der Ent & Visser host volatiles (Dickens, 1999, 2000, 2002) could be used to (1991) and Boiteau (2000) reported that yellow is attractive augment the attractiveness of trap crops to colonizing to L. decemlineata. Four 1.27-cm holes located on the pot adults in the field. Subsequent insecticide application to a floor allowed rainwater to drain freely. trap crop after colonization may decrease the frequency of The three-component plant attractant (Dickens, application, spray area, total volume and associated 2000, 2002) comprised (Z)-3-hexenyl acetate 98% (Sigma management costs for a crop system at the same time as Chemical Co., St Louis, Missouri) ( /–)-linalool 97% maintaining adequate pest control. þ (Sigma Chemical Co.) and methyl salicylate 99% (Aldrich Whole-field insecticide applications can create strong Chemical Co., St Louis, Missouri). Cigarette filters (7.1 mm selection pressure for resistance development (Olson et al., diameter 2.54 cm length) made of cellulose acetate and 2000; Zhao et al., 2000). Because insecticide application in  wrapped in SaranTM (Filtrona Richmond Inc., Richmond, main economic crop areas was reduced by 50% in Virginia) served as release substrates for the attractant. Chausov’s (1976) system when grown in the presence of an Three microlitres of each attractant component were diluted early planted trap crop, L. decemlineata were exposed to in 0.5 mL of a slow release formulation comprising one less major selection event than those in areas not pro- polyethylene glycol (20%), methanol (42.5%), glycerol tected by a trap crop. A reduction in the number of insecti- (25 ) and distilled water (12.5 ) (Dickens, 1989) and cide applications may better maintain a balance of % % then injected into the cigarette filters. Control filters susceptible and resistant genotypes within a pest popula- contained only 0.5 mL of the slow release formulation. tion. It may also serve the dual purpose of decreasing the A cigarette filter containing either the volatile-baited or likelihood of resistance development at the same time as control solution was secured by wire in the open side of a reducing the impact of conventional pest management on 5.1-cm diameter Petri dish. This one-sided plastic lure nontarget organisms and the production environment, such assembly enabled release of volatiles at the same time as as in 1979 when the carbamate aldicarb was