Evaluation OP Commercial Materials Applied for Citrus Thrips Control in California, 1983

Materials were evaluated using alternative application techniques in three experimental plots in the San Joaquin Valley and in one plot in Riverside. All plots contained sufficient border rows to protect data trees from drift; the number of single tree replicates per treatment are noted in the tables. Treatments were applied approximately at petal fall at the following sites and on the following dates: Test 1, Borchard grove, Terra Bella, 17 May; Test 2, Runciman grove, Wooklake, 19 May; Test 3, Muller grove, Ivanhoe, 24 May; Test 4, Citrus Research Center, Riverside, 19 May. Application methods included: hand sprayer (outside coverage using a Hardie hand-gun at 500 lb/in2 and 200 gal/acre); CP267 full RPM (application with an FMC CP267 speed sprayer, air velocity 130 mph and 200 gal/acre unless otherwise noted); CP267 half RPM (air velocity 130 mph and 200 gal/acre unless otherwise noted); CP267 half RPM (air velocity reduced to 80 mph by reducing fan speed with increase in pump pressure to maintain 200 gal/acre unless noted); Helicopter -- Test 1 (Bell 3B2 helicopter application at indicated speed and gallonage (courtesy of Gilbert Aviation Indutries, Inc.); Kinkilder (Kinkilder low-volume mist sprayer with attached 10-ft citrus tower at ca. 100 gal/acre). Fruit scarring counts, for scars caused by citrus thrips, were taken approximately 1 month before harvest on all fruit on the exterior of the tree from knee to eye level (scarring is more severe on outside fruit). Scars were rated as slight (incomplete ring scar) or severe (complete ring scar or extensive surface scarring; severe scarring equivalent to level causing fruit downgrading in a normal year). Economic scarring levels are approximately 5% severe scars.