Citrus Cutworm Pesticide Efficacy Trials, 1994
Abstract Insecticides for the control of citrus cutworm were evaluated on 29 yr old ‘Washington navel’ orange trees at the Lindcove Research and Extension Center, Exeter, CA. The insecticide applications were made on 28-29 Apr with a Bean hand-sprayer at 450 psi and approximately 300 gpa (3—4 gal/tree). Lorsban was applied after sunset to reduce the detrimental impact of the insecticide on honey bees in the orchard. The 14 treatments were assigned based on pretreatment sampling of larvae and each of the treatments were applied to single trees, replicated 8 times. Larval collections were accomplished by placing a canvas beating sheet (112 cm × 75 cm) beneath the outside foliage of the tree and vigorously shaking the foliage 10 times. Citrus cutworm larvae which fell onto the canvas were counted and recorded by instar, then returned to the foliage. Pretreatment larval counts were made on 20 Apr by sampling the northeast and southwest quadrants of each tree. Post treatment counts were made on 9 May by sampling all four quadrants of each sample tree, again recording each instar. Percentage of scarred fruit due to citrus cutworm feeding was evaluated on 7 Sept on each of the sample trees within a 2 m vertical swath around the tree beginning approximately 20 cm above ground level and extending approximately 40 cm into the tree interior. In 1994, late Apr and early May temperatures at Lindcove ranged from relatively cool to warm, with daily maximums between 61°F and 90°F (mean of 72.5°F).