California Red Scale Pesticide Efficacy Trial, 1995

Efficacy of three insect growth regulators (IGR) and a new chemistry insecticide for the control of CRS were compared with an organophosphate insecticide and an untreated check. The insecticides were applied to 12 year old ‘Washington navel’ orange trees at the Lindcove Research and Extension Center, Exeter, CA. Various rates, timings, and numbers of insecticide treatments were applied to single trees, replicated 10 times, based on pretreatment densities of CRS. Admire was applied to the soil on 4 May and irrigated for 8 hours. Foliar treatments were timed for emergence of 1st generation (25, 26 May) or 2nd generation (2, 4 Aug) scale crawler activity. All foliar spray applications were made with a Bean hand-sprayer at 450 psi and approximately 1200 gpa (14–15 gallons per tree). Twig sampling was conducted by counting 1 st and 2nd instar scale and 3rd instar female scale from five randomly selected 2 yr-old twig samples per tree. Five randomly selected fruit per tree were also evaluated when fruit became available. At harvest, the percentage of fruit infested with ≥10 CRS was evaluated for each of the treatments.