Control of Green Scale on Cape Jasmine with Imidacloprid, Hawaii, 1993

Efficacy trials were conducted from 27 Oct through 23 Dec at the University of Hawaii at Manoa, Waiakea Experiment Station in Hilo. One year old established plants, approximately 2 ft tall, growing in 9 by 10 inch polyethylene bags under a fiberglass greenhouse were used in this study. Treatments consisted of 4 replicates with 2 plants per replicate. Treatments were evaluated by taking visual counts on the number of live and dead scales from three leaves selected at random from the bottom, center and top of each plant on 27 Oct (pretreatment), and 12, 18, and 23 Nov. To determine efficacy against crawlers and eggs, counts were taken on 30 Nov, and 6, 16, and 23 Dec using a dissecting microscope. Imidacloprid 0.62G (NTN 33893) was applied once at 0.009 g AI per bag (0.001 g Al/inch diameter) on 28 Oct 93 and watered immediately after treatment. Percentage mortality was calculated using the mean number of live and dead scales from two leaves (one per plant) from each location. Percentages were transformed to arcsine sqrt and subjected to t test. Back transformed means are presented. Plants were also observed weekly for phytotoxicity.