Distribution of Helicoverpa zea eggs in a cotton/soybean landscape

In recent years cotton acres have declined substantially in the Mid-South while corn and soybean acres have expanded. As a result, there is increased interest from producers and industry in the Mid-South to have commercial access to transgenic soybean varieties that express the Bt toxins to assist management of lepidopteran pests. Currently, soybeans are valued as an influential component to the natural refuge concept in producing susceptible individuals to the H. zea and H. virescenspopulation. Further research must be generated to understand the possible influence of Bt soybeans to the natural refuge system in place for cotton.

An experiment was conducted to quantify the bollworm and budworm plant host preference between soybean and cotton based on oviposition. Paired male and female adults were released in 20 ft. x 20 ft. screen cages placed over three rows of cotton and three rows of soybean when both crops were at peak bloom. Three days after infestation, five foot of row were removed and visually sampled for number of eggs present and location of eggs deposited on plants. Differences were observed in oviposition on crop hosts and between species.