Comparison of Insecticides Against Oblr on Apple, 1997

Abstract

Abstract Treatments were applied with a truck-mounted airblast sprayer calibrated to deliver 100 gallons of water/acre to 0.25 acre plots of apple trees in two orchards: (1) ‘Idared’ trees (Nesbitt orchard), which were 10 ft high, 12 ft wide and with rows 20 ft apart, (2) ‘Delicious’ trees (Buhr orchard), which were 10 ft high, 9 ft wide and with rows 20 ft apart. Treatments were arranged in a RCB design and replicated once in each orchard. Six schedules of a mixture of Confirm 2F (4.5 oz (AI)/acre) and Latron B-1956 (16 oz/acre) were compared: (1) An initial spray was applied at the first catch of moths (20 Jun) followed by sprays on 1 Jul, 16 Jul and 30 Jul; (2) An initial spray was applied at the first catch of moths (20 Jun), followed by a spray at first hatch (1 Jul); (3) An initial spray was applied at first catch (20 Jun) followed by another spray on 16 Jul; (4) The initial spray was applied at the estimated mid-point of cumulative egg hatch (16 Jul), followed by a spray on 30 Jul; (5) The initial spray was applied at first hatch (1 Jul) followed by another spray at the estimated mid-point of cumulative egg hatch (16 Jul); (6) spray was applied at first hatch (1 Jul), followed by sprays on 16 Jul and 30 Jul. Also, Confirm 2°F (4.5 oz (AI)/acre) + summer oil, Confirm 2°F (4.5 oz (AI)/acre) and Confirm 2°F (3.0 oz (AI)/acre) 1 Latron B-1956 (16 oz/acre) were applied on 1 Jul, 16 Jul, and 30 Jul. Three treatments of Spinosad 2 SC were compared: (1) Spinosad 2 SC (1.0 oz (AI)/acre) applied at first hatch on (1 Jul), followed by additional sprays on 16 Jul and 30 Jul; (2) Spinosad 2 SC (1.25 oz (AI)/acre) applied at first hatch (1 Jul), and on 16 Jul and 30 Jul; (3) Spinosad 2 SC (1.0 oz (AI)/acre) plus Confirm 2°F (3.0 oz (AI)/acre) applied at first hatch (1 Jul), 16 Jul, and 30 Jul. Lorsban 50 W (24 oz (AI)/acre) was applied as a standard treatment at first hatch (1 Jul), 16 Jul, and 30 Jul. Check plots were not sprayed with insecticides during the test. Summer populations of larvae were compared by examining 20-50 growing terminals from each of five randomly selected trees/plot for live larvae on 29 Jul. Fruit damage from the first summer generation of larvae was estimated initially on 11, 12 Aug by sampling 100-200 apples from each of 4 randomly selected trees/plot. At harvest (30 Sep, Buhr orchard and 3 Oct, Nesbitt orchard), 200 apples were picked from each plot and OBLR damaged fruit was classified according to USDA grading standards into the categories of “Fancy”, #1 and culls.