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Declining Pests Mean Increasing Profits

Pests_Increasing_corn.jpgMichigan State University Extension

Not long ago, the European corn borer (ECB) caused annual crop losses approaching $1 billion nationwide and $35 million in the Northeast. In recent years, widely adopted corn hybrids that express insecticidal toxins isolated from the soil bacterium Bacillus thuringiensis have been exceptionally effective for managing ECB.

"A drawback to using these hybrids has been the high cost of purchasing the seeds, which can decrease potential profits," explained John Tooker, assistant professor of entomology.

Now, a research team led by Tooker has found that populations of European corn borer have declined significantly in the eastern United States, suggesting that the use of so-called Bt corn may be unnecessary in some areas.

The researchers assessed damage caused by ECB larvae in Bt and non-Bt corn hybrids at twenty-nine farm sites across four growing zones in Pennsylvania over three years. They found widespread population declines of the pest similar to declines that have been found in the Midwest.

With less ECB damage, non-Bt hybrids in the study yielded just as well as Bt hybrids, noted Eric Bohnenblust, graduate student in entomology. "So this provides an opportunity for growers to generate greater profits by planting high-yielding non-Bt seed, which is much cheaper than Bt seed," he said. "Secondarily, planting more non-Bt corn will reduce the potential for ECB to develop resistance to Bt toxins as corn rootworms have done in about a dozen states so far."

Tooker said based on these results, the researchers would advise growers to scout their non-Bt acreage toward the end of the growing season. "If they have low ECB populations, we would recommend that in the next season they give competitive non-Bt hybrids a try on some of their acres because they could see better profits from growing non-Bt hybrids."

Sara LaJeunesse