Apple, Full Season Insecticide Evaluation, 1984

Abstract

Abstract Experimental insecticide treatments were applied in a comparative test to mature semi-dwarf York trees on 1 May (pink), 21 May (petal-fall), 6 Jun, 20 Jun, 6 Jul, 19 Jul, 2 Aug, 15 Aug and 29 Aug. Treatments were applied with a Bean 35 gal/min hydraulic sprayer operating at 400 psi. Single tree treatments were used and replicated 4 times in a randomized block design. Trees were sprayed to runoff. RAA populations were evaluated on 16 May by counting all colonies found in 3 min/tree and opening the leaves to determine survival from the 1 May treatments. Aphid colonies were counted again on 4 Jun (3 min/tree) to determine increases in population and effectiveness of the 21 May treatment sprays. WHAL populations were evaluated on 16 May by counting nymphs and adults on 25 leaves per replicate. Apple aphid populations were examined on 28 Jun by checking for live aphids on 10 randomly selected terminals/replicate. ERM populations were evaluated on 11 Jun, 26 Jul and 6 Aug by randomly collecting 25 leaves/replicate, brushing with a modified Henderson-McBurnie mite brushing machine onto glass plates and counting mites and eggs with the aid of a binocular microscope. SP counts were made on 7 Aug by counting adults and larva in a timed count of 3 min/replicate. On 8 Oct, 400 apples/treatment (100/rep) were harvested and evaluated. All significant damage was the result of feeding by the leafroller complex (RBLR, VL, TABM). Percent clean fruit is shown and allows for light damage from other pests. Average fruit size was measured and a finish rating of 1 to 5 (5 being worst) was given each apple.