Apple, Summer Pest Control, 1984

Sprays were applied to 4- or 5-tree plots in a randomized block design consisting of 5 replicates of each treatment. Each plot consisted of alternating Golden Delicious and York Imperial trees. Treatments were applied with a Friend Airmaster 393 sprayer driven at 2 mph using the alternate side technique of spraying (75 gpa/full spray). Rates for treatments are listed as amounts/acre/both sides spray. Application dates were: 7, 14, 21, 29 Jun; 9, 16, 23, 30 Aug; 6 Sep. Treatments which included Pydrin or Payoff were not applied on 6 Sep. Plictran 50WP (142 g/acre) plus Carzol 92SP (142 g/acre) was applied to all treatments on 19 Jul. Guthion 50WP (340 g/acre) was applied to all treatments on 31 Jul. Average temperatures were: Jun 70.3° F, Jul 71.3° F, Aug 72.6° F and Sep 60.9° F. Rainfall in inches totaled: Jun 4.42, Jul 5.86, Aug 7.33, and Sep 1.11. Effect of treatments on ERM was evaluated by counting mites several times during the season on samples of 20 leaves/tree (cv. York only), 100 leaves/treatment. Effect of sprays on the mite predator SP was evaluated by 3-min counts of adults and larvae around the periphery of test trees. Effectiveness on AA was evaluated by counting aphid-infested leaves on 20 terminals around the upper periphery of the tree. Effectiveness of chemicals on fruit feeders was assessed by scoring for injury all drops (Yorks only) after 1 Jul and 1 pick sample at harvest (Golds and Yorks). Apple samples averaged 222 fruits/replicate and 1110/treatment. Pest pressure was moderate throughout the season.