Apple, All Season Insecticide Test, 1984

Abstract

Abstract A 14-year-old orchard at the Rutgers Tree Fruit Research Center, Cream Ridge, N.J. was used in this test. Sprays were applied to single-tree plots consisting of 2 replicates each of Red Delicious and Golden Delicious arranged in a randomized complete block design. Trees were sprayed to runoff, ca. 6 gal/tree, using a hydraulic sprayer equipped with a handgun and operated at 250 psi. Spray dates were 1 May (P), 24-25 May (PF), 11 Jun (1C), 10 Jul (2C), 9 Aug (3C) and 30 Aug (4C). For disease control the entire orchard was sprayed with Captan and Polyram as needed. ERM estimates were made by randomly picking 25 leaves per tree, brushing mites onto glass plates and counting motile mites. Descriptions of sampling methods for various insects listed in table 1 are as follows: WALH = white apple leafhopper damaged leaves/500 leaves/tree, STLM = spotted tentiform leaf miner damaged leaves/500 leaves/tree, EASF = European apple sawfly damaged fruit clusters/100 fruit clusters/tree, AA = average apple aphids/20 terminals/tree, RAA = rosy apple aphid colonies/tree. In table 2, ERM days = total accumulation of mite days from petal fall (24 May) to last counting date. Mite days were calculated as follows; MD = MDl + [(Ml + M2)/2 x Y], where MDl = mite days already accumulated, Ml = avg ERM/ leaf on a given counting date, M2 = avg ERM/leaf on the next counting date after Ml and Y = number of days between Ml and M2. Data were transformed to log x + 1, x + 0.5 or arcsin x prior to analysis of variance and comparison of means. (P = 0.05; DMRT).