Apple, Miticide Evaluations, 1987

Abstract

Abstract Treatments were applied to 5-yr-old trees using single tree plots arranged in a randomized block design and replicated 5 times. Trees were sprayed to runoff using a Bean 35 gal/min hydraulic sprayer operating at 400 psi. Application dates varied from treatment to treatment. Refer to the table for application dates for each material. Mites and eggs were counted by randomly selecting 20 leaves/replicate, brushing onto glass plates with a modified Henderson-McBurnie brushing machine, and counting all motile forms and viable eggs with a binocular microscope. Mite predators were kept out of these plots during the early season with sprays of Sevin and Asana. ABG-6162A was applied at pink bud stage on 2 plots and at pink and petal-fall on 3 plots. Other treatments were aplied on 18 Jun, when populations on the check were greater than 3 mites/leaf. Subsequent applications were made on each treatment at the same threshold until 1 Aug, when miticide applications were discontinued. The number of applications and the total number of accumulated mite days for the season are important for evaluation of each treatment.