Birch, Efficacy of Selected Insecticides Against GYPSY Moth Larvae, Wooster, Oh, 1989

Birch, 20-30 cm tall, growing in 1-gal containers in a greenhouse at the main OARDC campus were used to evaluate insecticides against 4th instars. A C02 compression sprayer operating at 20 psi with a single Teejet SS8004 flat-fan nozzle was used to apply treatments to runoff. Modified 1-gal (3.9 liter) Fonda cartons were used to prevent larval escape. Tops and bottoms were removed from the cartons, and a bottom was secured around the base of each tree stem prior to larval placement and spray application. Five 4th-instar larvae were placed on each of 4 single-tree replicates, and treatments were applied. Then, cartons were secured to bottoms and nylon organdy cloth was fitted over the top. Two seperate tests were conducted under the same conditions and procedures. Sprays were applied 19 Aug (Test #1) and 28 Aug (Test #2). Treatment effectiveness was evaluated 21 Aug and 30 Aug, respectively, by counting live and dead larvae 48 h posttreatment.