Evaluation of different trap types and lures for capturing emerald ash borer adults in low density populations
22nd USDA Interagency Research Forum on Invasive Species
Effective methods for early detection of newly established, low density emerald ash borer (EAB), Agrilus planipennis Fairmaire, infestations remain a critical need (Poland and McCullough 2006). Following the discovery of EAB in 2002, most field studies to evaluate traps and lures were conducted in areas where A. planipennis populations were at moderate to high densities (Francese et al. 2005, 2008; Crook et al. 2008, 2009; Lelito et al. 2008). In such sites, however, many ash trees exhibit canopy decline and dieback and emit stress related volatiles, all of which may affect either the visual response of beetles to traps or the olfactory response of beetles to the lures under evaluation. Once promising traps and lures have been identified, ideally, they should be assessed in sites where EAB density is at low levels and few, if any, trees are symptomatic or stressed by larval feeding (Marshall et al. 2009, 2010). A number of studies have been conducted to compare the most promising trap types and lures for EAB at sites with low levels of EAB infestation. In one study, light green and purple double-decker traps were compared to purple prism traps hung about 3 m above ground in the canopy, or girdled trees in a 16.2 ha forested site in central Michigan with no symptoms of EAB infestation. Each double-decker trap consisted of 3 m tall 10 cm diameter PVC pipe with a prism panel mounted at the top and a second prism panel 60 cm below it. Double-decker traps were set on T-posts in the open, approximately 3 m from the edge of ash stands. The site was divided into 16 blocks each with four 50 by 50 m cells. One trap type was randomly assigned to each cell within a block. A total of 87 EAB were captured during the experiment. Purple double-decker traps baited with a blend of ash leaf volatiles (cis-3-hexenol, trans-2-hexenol, hexanal, and trans-2-hexenal), Manuka oil, and ethanol captured more EAB (65 percent of all EAB captured) than similarly baited, green doubledecker traps (18 percent) and sticky bands on girdled trees (11 percent). Purple traps baited with Manuka oil and placed in the canopies of live ash trees captured the fewest beetles (5 percent). At least one EAB was captured on 81 percent of the purple double-decker traps, 56 percent of the green double-decker traps 42 percent of sticky bands, and 25 percent of the purple canopy traps. In another study, light green or purple double-decker traps were compared to light green or purple prism traps hung about 4.5 m above ground in the canopy of ash trees. All traps were baited with cis-3-hexenol and an 80:20 blend of Manuka and Phoebe oils. There were 21 replicates at six different field sites that ranged in EAB infestation level from extremely low with no symptoms to moderate or high populations. Traps were spaced at least 15m apart with 25 m between replicates. Light green canopy traps caught significantly fewer EAB than the other trap types. Overall, double-decker traps captured more EAB than canopy traps, and purple traps were more attractive than light green traps. Differences were pronounced at the low density sites while at sites with higher EAB populations, differences among trap designs were not significant. All of the double-decker traps (both colors) and purple canopy traps captured at least one EAB each, while only 64 percent of the light green canopy traps did.
Different lures were also compared for light green or purple prism traps hung at least 10 m above ground in the canopy of ash trees. Traps were baited with cis-3- hexenol, an 80:20 blend of Manuka and Phoebe oils, or both. There were 17 replicates at three sites with EAB populations that ranged from low/moderate to high. For all sites and both trap colors combined, traps baited with cis-3-hexenol or both lures captured more EAB than unbaited traps, while traps baited with the 80:20 blend were intermediate. Males were significantly more attracted to traps with lures that contained cis-3-hexenol than to the 80:20 blend alone or unbaited traps. The number of females captured did not diff er significantly between treatments. For both sexes combined, more EAB were captured on purple than on light green traps. Females were significantly more attracted to purple traps but there was no difference in number of males captured between light green and purple traps. The differences in male and female responses to the different treatments and colors were most pronounced at the site with low EAB populations. In a similar study, light green prism traps baited with cis-3-hexenol or the 80:20 blend of Manuka and Phoebe oils were compared to purple prism traps baited with the 80:20 blend. All traps were hung at least 6 m above ground in the canopies of ash trees. There were 160 replicates at sites with low EAB densities in Indiana, Kentucky, Maryland, Michigan, Minnesota, Missouri, New York, Ohio, Pennsylvania, West Virginia, and Wisconsin. More males were captured in light green traps baited with cis-3-hexenol than in purple traps baited with the 80:20 blend, while light green traps baited with the 80:20 blend were intermediate. There were no differences in female trap catches between treatments, but they tended to prefer purple traps baited with the 80:20 blend. Detection rates were similar for all three treatments; 52 percent of light green traps baited with cis-3-hexenol, 59 percent of light green traps baited with the 80:20 blend, and 57 percent of purple traps baited with the 80:20 blend captured at least one EAB. Overall, at sites with low EAB densities, double-decker traps appear to be more attractive than prism traps hung 3-5 m above ground in the canopy. Studies using only prism traps hung at least 6 m above ground in the canopy showed males tended to prefer light green traps baited with cis-3-hexenol, while females tended to prefer purple traps baited with an 80:20 blend of Manuka and Phoebe oils. A combination of trap designs and lures may improve the likelihood of attracting both sexes, which could increase the potential for capturing at least one beetle.
Crook, D.; Khrimian, A.; Francese, J.A.; Fraser, I.; Poland, T.M.; Sawyer, A.J.; Mastro, V.C. 2008. Development of a host-based semiochemical lure for trapping emerald ash borer, Agrilus planipennis (Coleoptera: Buprestidae). Environmental Entomology. 37: 356-365.
Crook, D.J.; Francese, J.A.; Zylstra, K.E.; Fraser, I.; Sawyer, A.J.; Bartels, D.W.; Lance, D.R.; Mastro, V. 2009. Laboratory and field response of the emerald ash borer (Coleoptera: Buprestidae) to selected regions of the electromagnetic spectrum. Journal of Economic Entomology. 102: 2160-2169.
Francese, J.A.; Mastro, V.C.; Oliver, J.B.; Lance, D.R.; Youssef, N.; Lavallee, S.G. 2005. Evaluation of colors for trapping Agrilus planipennis (Coleoptera: Buprestidae). Journal of Entomological Science. 40: 93-95.
Francese, J.A.; Oliver, J.B.; Fraser, I.; Lance, D.R.; Youssef, N.; Sawyer, A.J.; Mastro, V.C. 2008. Infl uence of trap placement and design on capture of the emerald ash borer (Coleoptera: Buprestidae). Journal of Economic Entomology. 101: 1831-1837.
Lelito, J.P.; Fraser, I.; Mastro,V.C.; Tumlinson, J.H.; Baker, T.C. 2008. Novel visual-cue-based sticky traps for monitoring of emerald ash borers, AGrilus planipennis (Col., Buprestidae). Journal of Applied Entomology. 132: 668-674.
Marshall, J.M.; Storer, A.J.; Fraser, I.; Beachy, J.A.; Mastro, V.C. 2009. Eff ectiveness of differing trap types for the detection of emerald ash borer (Coleoptera: Buprestidae). Environmental Entomology. 38: 1226-1234.
Marshall, J.M.; Storer, A.J.; Fraser, I.; Mastro, V.C. 2010. Effi cacy of trap and lure types for detection of Agrilus planipennis (Col., Buprestidae) at low density. Journal of Applied Entomology. 134: 296- 302.
Poland, T.M.; McCullough, D.G. 2006. Emerald ash borer: invasion of the urban forest and the threat to North America’s ash resource. Journal of Forestry. 104: 118-124.
Therese M. Poland, Deborah G. McCullough, Andrew J. Storer, Jordan M. Marshall, and Ivich Fraser (2011).
Evaluation of different trap types and lures for capturing emerald ash borer adults in low density populations. Presented at 22nd USDA Interagency Research Forum on Invasive Species, Annapolis, MD.