Control of Second Instar Beet Armyworm Larvae on Chrysanthemum, Summer, California, 1986

Two rates of Dimilin 25W were evaluated for control of second instar beet armyworm larvae. Ten 4-week-old chrysanthemum plants were used per treatment. Plants were sprayed with a 1 gal B&G hand sprayer at 55 psi until runoff 3 Sep. After the plants were allowed to dry, 5 second instar beet armyworm larvae were placed on each plant. The larvae were confined to the plants using an inverted, ventilated 1 qt plastic container. Mortality was assessed after 48 h and each surviving larva was placed individually in a 1 fl oz plastic cup filled with a sufficient amount of untreated commercial beet armyworm diet. Mortality was assessed at 48 h intervals thereafter until all surviving larvae pupated. In addition, percent mortality at adult emergence was also determined for all treatments. The data were subjected to arcsin square root transformations prior to ANOVA.