Laboratory Evaluation of Neem-seed Extract Against Larvae of the Cabbage Looper and Beet Armyworm (Lepidoptera: Noctuidae)1

Neem-seed extract, incorporated into an artificial diet at 0.02, 0.2, and 2.0% (wt/vol) prolonged development and induced mortality in all larval stages of Trichoplusiani (Hübner) and Spodoptera exigua (Hübner). Only one nonreproductive T. ni adult female was produced at the lowest concentration (0.02%) when fifth instars were exposed to the diet. No pupae were formed by S. exigua larvae, regardless of stage treated or extract concentration tested. Larva mortality of both species was more pronounced during ecdysis, indicating activity similar to that of other insect growth regulators.