Insecticidal Control of Brown Citrus Aphid on Sweet Orange, 1997
Abstract The trial was conducted in a commercial block of four-year-old ‘Valencia’ orange rooted to Carrizo citrange planted on a 12 X 24 ft. spacing. A RCB block design was used with 4 replications in separate rows and 5 treatments distributed in single-row plots separated by at least one guard tree. At least 10 new shoots not yet fully expanded and heavily infested with BCA were tagged at the onset of the trial. Foliar treatments were sprayed by hand on 24 Jun using a trailer-mounted sprayer equipped with a 13” brass GunJet Spray Gun fitted with a hardened stainless steel #3 orifice disc-type nozzle. The sprayer was supplied by a gasoline-powered diaphragm pump operating at 200 psi and calibrated to deliver 101 gpa. Tagged colonies were evaluated one day prior to treatment and 2, 7, and 14 DAT using a rating scale of 0 to 6:0 = no aphids, 1 = 1-12 aphids, 2 = 12-50 aphids, 3 = 50-150 aphids, 4 = 150-500 aphids, 5 = 500-1,000 aphids, and 6 = > 1,000 aphids. Average colony size was estimated at 4.6 prior to treatments. In addition, aphids were counted on 5 new pieces of the youngest flush that could be found on each tree on 7, 14, 21 and 28 DAT.