Apple, Scale Control, Yakima, Wa, 1982

Abstract A dormant application of parathion 25 WP or Advantage 4EC was made on 9 Apr, 1982 to a block of mature ‘Red Delicious’ apple trees for control of San Jose Scale. Parathion was applied at 1.0 lb (AI)/acre with an air blast sprayer in 200 gal of spray/acre. Advantage (2 lb (AI)/acre) was applied with an air blast sprayer also in 200 gal/acre, aerially at 14 gal/acre and as a combined aerial-air blast sprayer application. The combined application was to determine if the aerial application would improve control in the tops of the trees. Each application included 5 gal of superior oil/acre. On 8 and 9 Jun, the efficacy of each treatment was determined by counting live scales out of 100 on each of 5 twigs taken at two levels from 25 randomly selected trees per treatment. On 1, 7, and 14 days posttreatment, 5 twigs were taken at 2 levels from 5 trees in each block treated with Advantage® for residue analysis. In the untreated block, and the parathion treatment, trees were too small to partition into high and low levels; therefore samples were randomly collected over the entire tree. At harvest, 50 apples from each of 5 trees were sampled to determine percent infestation.