Multi-state comparison of emerald ash borer detection tools: A 5 year synthesis
22nd USDA Interagency Research Forum on Invasive Species
The need for effective detection of emerald ash borer (EAB), Agrilus planipennis Fairmaire, early in the infestation timeline has been evident since this pest was first discovered in 2002. Since 2006, we have compared potential trap and lure combinations at low emerald ash borer population densities in order to identify which traps may have the highest detection efficiency. The objectives of this study over the years 2006-2010 were to: (1) compare the effectiveness of different detection tools across various states; (2) identify the most effective of the available tools for EAB detection at low density; and (3) develop monitoring and trapping recommendations for managers in states with and without EAB infestations. States where traps were established and the trap types tested varied across years. Indiana, Michigan, and Ohio, had sites throughout the experiment (2006-2010), while Kentucky (2010), Minnesota (2010), Missouri (2009- 2010), New York (2009), Pennsylvania (2008-2010), Virginia (2009), Wisconsin (2009-2010), and West Virginia (2010) had trapping sites during 1-3 years. The only trap consistently used across all years was a current year girdled tree with a plastic, sticky trap wrapped around the bole of the tree. While the mean number of EAB captured per trap type in 2006 was not significantly different, girdled trees wrapped with purple glue had the greatest capture rates, as well as the highest rates of detection. However, due to the high variability of capture rates, identification of a single successful trap was not possible in 2006. Five of the eight trap types resulted in a third or less of the traps detecting EAB, suggesting that they may not be effective detection tools. Girdled, mature ash trees (>30 cm DBH), wrapped with a plastic, sticky trap captured the greatest number of EAB adults in 2007. In addition, the mature trees also had the highest detection rates. While these trees appear effective, it can be difficult to find ash trees of suitable size, and to acquire permission from property owners or managers to girdle such large trees. The large mature trees also become hazards when girdled and are difficult to remove. As with the traps in 2006, there was no significant difference in the number of EAB captured per trap in 2008. However, the purple prism traps hung at 6 m with manuka oil lure and at 1.5 m with phoebe oil lure had detection rates above 0.50, suggesting that after a single flight season, those traps may be effective. Natural fluctuations in population size and EAB behavior may play important roles in the effectiveness of detection traps. Th is is evident in the variability of detection rates in current and previous year girdles in 2006, 2007, and 2008. For 2009, only the current year girdle had significantly fewer EAB captured than the green prism trap hung at 13 m. The green traps at 13 m had the greatest number of EAB captured, but had lower detection rates than the purple prism trap at 6 m, orthe double-decker tower trap. Both the purple prism trap at 6 m and the double-decker tower trap detected EAB in more than 50 percent of cases. The variability in effectiveness of the current year girdle continued from previous years, with less than a quarter of the traps detecting EAB in 2009, with previous years ranging from 1/3 to 1/2 of the traps. Similar to 2006 and 2008, there was no significant difference between trap types in 2010. The different green and purple prism traps had detections with over half of the traps. However, for each prism trap type individually, only approximately one-third of the sites had detections on all three replicates of the same trap type. Th is is an indication that landing behavior of EAB influences the success of a trap. It may be necessary for numerous traps to be placed within a stand to effectively and operationally identify a stand as being negative for EAB. The current year girdled tree was the only trap used in all 5 years of the study, but it was not consistent in capture or detection rates. Since the mean diameter was not significantly different between years for the current year girdle, EAB population density most likely varied enough between years and sites to cause variation in the effectiveness of the current year girdle. The degree at which EAB population density and behavior influences the effectiveness of an individual trap type is unknown. Because of this uncertainty, the longterm, multiyear use of a single trap type will likely result in unclear detection efforts. Increasing trap diversity, numbers of traps, and total trapping surface area may be the most effective strategy for EAB detection. Analysis of detections and the number of traps used each year showed that the odds of detecting EAB increased by 27 percent with each addition of a trap. Continued refinements of traps, lures, and combinations will also improve EAB detection efforts.
Marshall, J.M.; Storer, A.J.; Fraser, I.; Beachy, J.A.; Mastro, V.C. 2009. Eff ectiveness of diff ering 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.
Marshall, J.M.; Storer, A.J.; Fraser, I.; and Mastro, V.C. [In Press]. A predictive model for detection of Agrilus planipennis larvae in girdled ash (Fraxinus spp.). Journal of Applied Entomology. doi: 10.1111/j.1439-0418.2010.01525.x
Jordan M. Marshall, Jessica A. Beachy, Ivich Fraser, Andrew J. Storer, and Victor C. Mastro (2011).
Multi-state comparison of emerald ash borer detection tools: A 5 year synthesis. Presented at 22nd USDA Interagency Research Forum on Invasive Species, Annapolis, MD.