Fall Webworm Control with Insect Growth Regulators (Igr), 1984

Individual fall webworm nests and surrounding foliage were sprayed to point of runoff using a 2-gallon compression sprayer. The average amount of spray used to treat individual nests among the treatments ranged from 167 to 294 ml. Spray solutions were mixed on the basis of g (AI)/liter. Nine nests were sprayed with each IGR. On each sample date, 3 nests pei treatment and 3 untreated controls were cut from branches, placed in plastic bags and held under refrigeration until examined (usually within 24 h). Each nest was examined and percent larval mortality determined. Average length of larvae in 3 nests sampled at treatment ranged from 9.9 to 19.3 mm (equivalent to 3rd to 5th instars). Accumulative precipitation for the test period totalled 1.43 in., all of this occurred prior to the 5 DAT sample date.