Mite Airblast Experiment on Apple, 1997

Abstract

Abstract Experimental and registered acaricide treatments were applied to single-tree plots in a RCB design consisting of three replicates of ‘Yorking’ and one replicate of ‘Golden Delicious’. The trees were planted to a spacing of 20 X 20 ft and were 24 years old. All treatments were applied with a Myers Mity Mist sprayer calibrated to deliver 100 GPA, driven at 2.4 mph for a complete spray. All treatments were applied as complete sprays except for the Pyramite treatment that was applied as two alternate row middle applications. All plots received a regular maintenance schedule of fungicides (Dithane 75 DF, Nova 40 WP, Topsin 85 DF, and Ziram 76 WP) and nutrients (CaCl). Post-bloom insecticides (Guthion 50 WP and Imidan 70 WP) were applied as needed at 1- to 2-week intervals beginning at petal-fall in early May. Effectiveness of the treatments on ERM, AF and ZM was evaluated by counting the mites at approximately weekly intervals during the season on samples of 25 leaves/tree, 100 leaves/treatment. The predatory mite SP was observed by making 3-min counts of adults and larvae around the periphery of the trees. Mite pressure was high. The cumulative number of mite days was determined for each treatment.