Dilute Acaricide Evaluation Experiment, 1988

Plots consisted of single trees in a randomized block design with 2 replicates of ‘Golden Delicious’ and 2 replicates of ‘Delicious,’ both spur types. The trees were planted to a spacing of 20 x 35 ft. Experimental sprays were applied to run-off with a handgun from a truck-mounted John Bean sprayer equipped with a 35 gal/min pump. Approximately 5.6 gal of spray was applied to each replicate tree (350 gal/acre) except where noted. Spray dates were as follows: 22 Jun, 29 Jun (UBIA-1335 and Omite treatments only), 7 Jul (all treatments but EL-193136 at 0.168 lb [AI]/100 gal, UBIA-1335, and Omite treatments), 18 Jul (Vendex 4 L, Omite 6 E, and Omite 30 W treatments only). General sprays of fungicides (Benlate, Polyram, Manzate, Bayleton, Dithane M-45), insecticides (Lorsban, Phosphamidon, Guthion, Sevin, Pydrin), and calcium chloride were made at 1- to 2-wk intervals throughout the experiment with a Friend Airmaster at 50 gal/acre. Effectiveness of materials against mites was evaluated by making several counts on random samples of 25 leaves/tree. Russet ratings are based on 30 ‘Golden Delicious’ apples/replicate. Fruits were rated as 1 (no russeting), 2 (light russeting), 3 (moderate russeting), or 4 (severe russeting). Possible ranges were 30-60 (none to light), 60-90 (light to moderate), and 90-120 (moderate to severe).