Apple, Obliquebanded Leafroller Control with Azadirachtin, Bacillus Thuringiensis and Chlorpyrifos in Spring, 1995

Neemix, Dipel 2X, and Lorsban 4E were evaluated for their ability to control OBLR larvae of the overwintering generation. The test was conducted in apple orchards at Milton-Freewater, OR and Mattawa, WA. Trees were 3-yr-old Fuji on dwarfing roots at Milton-Freewater and 3-yr-old Delicious on dwarfing roots at Mattawa. Treatments were applied to 3-tree plots replicated 5 times at Milton-Freewater and 12-tree plots replicated 5 times at Mattawa in 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 at Milton-Freewater were 5 Apr (pink) and 25 Apr (petal fall), and at Mattawa they were 5 Apr (pink) and 9 May (petal fall). The approximate application timings with regard to plant development stage are shown in the table. The post-treatment evaluation was made on 8 May in Milton-Freewater and the total number of live OBLR larvae found in a 2-min timed sample recorded. The post-treatment evaluation was made on 24 May in Mattawa and total number of live OBLR larvae on all trees of a treatment replication counted and collected to observe sublethal effects. Surviving larvae were reared on artificial leafroller diet in 3.25 oz portion cups until death or adult emergence. Any deformities possibly resulting from exposure to an insect growth regulator were recorded. A significant rainfall occurred less than 2 h after the pink application at Milton-Freewater. Weather was good during and after the other applications; however, spring weather in general was cooler and wetter than normal.