Control Of Hemlock Woolly Adelgid Using Imidacloprid in A 5% Ready-To-Use Trunk Treatment, 1995

An experiment was conducted at Longwood Gardens, located near Kennett Square, PA, to determine the effectiveness of trunk treatments of a 5% imidacloprid ready-to-use (RTU) product. All trees used for this study were moderately infested. On 27 May from 2-4 pm, the trunk of each tree below 4.5 St high was thoroughly treated using a backpack sprayer operating at 20 psi with a cone nozzle. Seven trees ranging in diameter at breast height (DBH) from 2-7 inches and 3 trees ranging in DBH from 21-25 inches were treated. Approximately 3.5 oz of material was applied to each 2-7 inch DBH tree and approximately 13 oz applied to trees with DBH > 21 inches. Conditions during treatment were: clear skies, air temperature of 25’C; and 52% RH. Treatments were evaluated between 3-13 Nov by randomly sampling 10 branches from each tree. The first 50 adelgids on the new growth of each branch were examined microscopically and classified as dead or alive.