Masters Theses

Date of Award


Degree Type


Degree Name

Master of Science


Entomology and Plant Pathology

Major Professor

Gary L. Lentz

Committee Members

Jerome F. Grant, Charles D. Pless


Cotton insect pests cost fanners beltwide $1.68 billion in 1995 due to yield losses, and insecticide and insecticide application costs. With increased insect resistance and environmental concerns, new and innovative control methods are needed. Several Bt cotton lines have been developed which carry an insecticidal protein from a soil bacterium inside the plant, which is toxic to many lepidopteran cotton pests. Bt cottons were evaluated for resistance to injury from the bollworm, Helicoverpa zea Boddie, and tobacco budworm, Heliothis virescens F., which are lepidopterans collectively called the Heliothine complex.

Data indicate that Bt cotton lines suffered significantly less Heliothine complex injury to squares and bolls throughout the season than conventional cultivars. Bt cotton lines did not require insecticide treatments for the Heliothine complex to prevent yield loss. These studies indicate that Bt cottons could play an important role in future cotton pest management and reduce insect control costs in production agriculture.

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