title: Feeding behavior and growth of corn earworm (Lepidoptera: noctuidae) larvae on Bacillus thuringiensis-treated (dipel 4L) and untreated meridic diet.
abstract: The effect of Dipel 4L in artificial diet on feeding behavior, occurrence on a specific diet, and growth of corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), was assessed in short-term tests. Third-, fourth-, and fifth-stage laboratory-reared and feral corn earworm larvae were evaluated. Arenas used for each assay included a non-Dipel diet, Dipel-containing diet, and a combination of the two diets. Larval activity was observed immediately after exposure to diet and at 6 and 18 h for third instars and at 6, 8, and 24 h for fourth and fifth instars, respectively. Feral and laboratory-reared third, fourth, and feral fifth instars avoided Dipel-treated diet when more suitable food was available. Third and fourth instars consistently preferred non-Dipel-containing diet when presented a choice of foods. Corn earworm growth was delayed when larvae were subjected to Dipel-treated diet in choice and no-choice assays compared with larvae provided untreated diet. Larvae presented a choice of diets grew more rapidly than those presented Dipel-treated diets in no choice arenas. Larval feeding frequency and weight gain were superior when larvae were supplied untreated diet than when restricted solely to a Dipel-treated diet. Larvae presented a choice of diets spent more time feeding and fed more frequently on untreated diet than Dipel-treated food. These data indicate that corn earworm presented a choice of Bacillus thuringiensis (Bt) and non-Bt diets may have an increased probability of completing development compared with those restricted to Bt-laced sources.
authors.affiliation: Dupont Agriculture and Nutrition, 501 Pine, Dumas TX 79029, USA.
authors.forename: Robert D
authors.initials: RD
authors.lastname: Bowling
authors.forename: Randall A
authors.initials: RA
authors.lastname: Higgins
authors.forename: Aqeel
authors.initials: A
authors.lastname: Ahmad
authors.forename: Gerald
authors.initials: G
authors.lastname: Wilde
mesh_terms: D000818:Animals; D001413:Bacillus thuringiensis / Q000502:physiology*; D002755:Choice Behavior; D004032:Diet; D005247:Feeding Behavior / Q000187:drug effects; D007814:Larva / Q000254:growth & development / Q000502:physiology; D009036:Moths / Q000254:growth & development / Q000502:physiology*; D010572:Pest Control, Biological