Detection of Emerald Ash Borer (Coleoptera: Buprestidae) in Ash (Fraxinus spp.) Crowns in the Southern United States: Comparing Panel Trap Color, Placement, and Lure

The emerald ash borer (EAB), Agrilus planipennis Fairmaire, is an invasive forest pest that is causing a rapid decline in ash (Fraxinus spp.). As EABs spread across North America to 35 U.S. states and 5 Canadian provinces, detection of the pest has proven difficult, especially at low population density sites. Panel traps have been commonly used in detection and monitoring of EAB populations. Over two sampling periods from 2016 through 2019, adult catches and detection rates were compared among four combinations of panel trap color, lure, and crown placement in southern Arkansas, northern Louisiana, and eastern Texas. The four combinations were as follows: (1) dark purple baited with (Z)-3-hexenol alone in the mid–upper crown; (2) light green with (Z)-3-hexenol plus (3Z)-lactone in the mid–upper crown; (3) dark purple with (Z)-3-hexenol in the lower crown; and (4) dark purple with (Z)-3-hexenol plus (3Z)-lactone in the lower crown. Mid–upper tree crown placement, ~13 m, of panel traps were more effective for EAB detection and adult capture, especially of males. The sex pheromone (3Z)-lactone deterred females but attracted males, while (Z)-3-hexenol attracted females. The green panel trap with both lures and mid–upper crown placement did not drastically increase male catches, contrary to previous studies at low EAB densities. The use of (3Z)-lactone on dark purple traps at low crown placements, such as those used in the National Survey Program, is not recommended for EAB detection due to its repellent effect on EAB females.