Apple, Control of the Pandemis Leafroller with Bacillus Thuringiensis in Spring, 1994

Different B. thuringiensis products were evaluated for their ability to control PLR larvae of the overwintering generation. The test was conducted in an apple orchard at the Tree Fruit Research and Extension Center. The trees were 15-yr-old spur type ‘Delicious’ on dwarfing roots. Treatments were applied to two-tree plots replicated five times using a RCB design. All treatments were applied with a handgun sprayer at 300 psi to the point of drip, simulating a dilute spray of approximately 400 gpa. Application dates were 18 and 27 Apr and plant development stages were full bloom and petal fall, respectively. The post-treatment evaluation was made on 9 May. One tree from each plot was examined, and the total number of live leafrollers found at a height between 4 and 8 ft in the canopy was recorded.