Apple, Dilute Test of Acaricides, 1987

Abstract

Abstract Plots consisted of single trees in a randomized block design with 2 replicates of'Golden Delicious' and 2 replicates of'Red Delicious,' both spur types planted to a spacing of 6.1 × 10.7 m. 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 5.0 gal of spray was applied per replicate tree. Spray dates were as follows: 9 Apr (ECO-3187 treatments), 22 Apr (Morestan and all ABG treatments), 11 May (ABG-6162, 1081 ml/100 gal), 5 Jun (all treatments but Morestan and ABG), 16 Jun (all treatments but ECO-3187), 19 Jun (ECO-3187 treatments only), 30 Jun (all treatments but ECO-3187), 13 Jul (all treatments but ECO- 3187 and Kelthane), and 23 Jul (all treatments but ECO-3187). Morestan was applied only on 22 Apr, Savey substituted thereafter. On 13 Jul, the rate of Savey was increased from 20.3 to 42.7 g/100 gal. On 23 Jul, Savey (42.7 g/100 gal) was added to the first two ABG-6162 treatments and Kelthane 4F (406 ml/100 gal was added to the last two ABG-6162 treatments. 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 sprayer at 50 gal/acre. Effectiveness of the materials on the mites was evaluated by making several counts on random samples of 25 leaves/tree, 100 leaves/ treatment. Mite population pressure was heavy throughout the summer. Russet ratings are based on 30 'Golden Delicious' apples/replicate, 60/treatment. 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).