Apple, Tufted Apple Bud Moth Control Tactics, 1992

Abstract

We sprayed 12-15 tree plots in a randomized block design. Each plot consisted of alternating trees of‘Yorking,’ and ‘Golden Delicious.’ These trees were planted 18 x 25 ft apart and were 13 years old. Experimental sprays were applied with a Friend Airmaster ‘309’ calibrated to deliver 100 gal/acre at 2.4 mph, except for the last Lorsban/Lannate treatment which received 50 gal/acre at 2.8 mph. Application timings were based on accumulated degree days following various biofix points (i.e., 1st egg hatch). Degree day calculations were based on minimum and maximum developmental thresholds of 45°F and 91°F, respectively. All applications were complete sprays, except for the second RH-5992 treatment, which was applied using the alternate row middle (ARM) method. A routine schedule of fungicides (Penncozeb, Rubigan, captan 50 WP and Topsin M 85 DF) was maintained throughout the experiment. ARM applications of Carzol 92 SP at 0.55 lb Al/acre 1.1 lb Al/acre (expressed as amount/acre for a complete spray) for white apple leaihopper control were made on 22 May and 1 Jun, respectively. Four ARM applications of Swat 8 E at 0.075 lb AI/acre (expressed as amount/acre for a complete spray) for control of apple aphid were made on 8, 19 and 29 Jun and 24 Jul. A complete application of Omite 6 E at 1.8 lb Al/acre was made on 8 Jul for mite control. Effectiveness of test chemicals on ERM and ZM was evaluated by counting mites several times during the season on samples of 25 random leaves/tree (100 leaves/treatment). Effect of sprays on SP was evaluated by 3-min counts of adults and larvae around the periphery of test trees. Effectiveness of chemicals on fruit feeders was assessed by scoring for injury to drop apples on 13 Aug, 2 and 14 Sep from the center two ‘Yorking’ trees. For ‘Golden Delicious,’ 120 apples were picked per replicate (40 apples on each of 6 trees). For ‘Yorking,’ 360 picked apples and 150 dropped apples per replicate were evaluated for injury. Pest pressure was high throughout the season.