Control of Gall-Making Psyllids on Hackberry—A two Year Evaluation, 1993-1994

Trials were conducted on field grown hackberry trees, approximately 12-ft in height, at a nursery in Ft. Collins, CO. Plots consisted of individual trees, separated by untreated trees, arranged in a RCB design with 5 replications. All treatments were applied using a Kioritz® soil injector delivering 1 fl. oz. of insecticide diluted with water in each of 4 injection holes/plant. Total amounts of insecticide applied per plant are indicated in the following table. Treatments of Bay NTN 33893 (imidacloprid) were applied on 26 May and Orthene 75S (acephate) treatments were applied 28 May 1993. Plots were periodically furrow irrigated and subsoil moisture was high since the site was bounded by irrigation ditches. Evaluations in 1993 were made 28 Jun by counting the total number of galls on individual branches surveyed at each of 4 cardinal points per tree. Trials in 1994 were evaluated by examining 5 leaves, collected randomly from a branch of each cardinal point of the trees, on two dates (1 Jul, 15 Aug).