Theses and Dissertations

Issuing Body

Mississippi State University


Gore, Jeffrey

Committee Member

Musser, Fred R.

Committee Member

Catchot, Angus L.

Committee Member

Cook, Donald R.

Committee Member

Dodds, Darrin M.

Date of Degree


Document Type

Graduate Thesis - Open Access



Degree Name

Master of Science


College of Agriculture and Life Sciences


Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology


The bollworm, Helicoverpa zea (Boddie), is an economically important pest of cotton and is becoming more difficult to control in the United States. This project was designed to develop a better understanding of the effects of resistance development and plant structures on the efficacy of Bt cotton and foliar insecticides. Experiments examined larval behavior and damage in current cotton varieties expressing proteins from Bacillus thuringiensis. Other experiments examined the effects of floral structures on the control of bollworm using foliar insecticides. Results suggest that larval feeding and avoidance behavior is dependent on point of eclosion. Fruiting form damage increased in two-gene cotton compared to earlier research but was low in cotton expressing the Vip3A protein. Increases in damage can lead to more frequent applications of foliar insecticides. Floral structures can hinder insecticide efficacy by reducing exposure. Results from these experiments will be important for refining management recommendations for bollworm in Bt cotton.



Cotton Incorporated United States Department of Agriculture