Genetically improved varieties were grown on 99% of Arkansas' 900,000 cotton acres last year.
Bollgard technology was introduced in the first enhanced variety in 1996. It contained a gene from the Bacillus thuringiensis bacterium (Bt) that was coded for production of a protein toxic to caterpillar pests.
Bollgard varieties are “highly effective” on tobacco budworms, says Bill Robertson, cotton specialist with the University of Arkansas (U of A).
“Neither of my colleagues nor I have ever collected tobacco budworms in Bt cotton,” says Jeremy Greene, Extension entomologist at the U of A.
Both scientists say the products are less effective on bollworms and farmers must routinely apply supplemental insecticides to control them.
However, producers have two new products, Bollgard II from Monsanto, and WideStrike from Dow AgroSciences. Both are labeled for use in 2005 and have the same gene to control budworms, but they have different secondary protein genes to provide bollworm control.
Greene warns that neither product provides protection against sucking insect pests, including plant bugs, stink bugs, aphids and thrips.
“With these enhanced technologies farmers will use fewer insecticide applications targeting caterpillars. They'll still have to spray for the sucking insects,” says Greene.”