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Extension > Source - Fall/Winter 2009 > Pest-control method can save $1.3 billion

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Pest-control method can save $1.3 billion

Growers make decisions based on '250 threshold'

New research shows that an Extension-led effort to change the way soybean growers practice pest control isn't just good for the environment. It's also good for the bottom line.

Plant with pests

For answers to questions ranging from budgeting to gardening, families have turned to Extension for help.

n fact, pest-control tactics developed by Extension entomologist David Ragsdale and his team can save U.S. soybean growers $1.3 billion over the next 15 years, according to an independent analysis by Michigan State University.

Ragsdale is one of several Extension faculty members doing research and outreach on integrated pest management (IPM). IPM advocates for using multiple tactics to control pests, including varietal selection, sampling, crop rotation and targeted insecticide use. An important aspect of IPM is learning to accept a certain amount of pests in a field.

"We're not into pest eradication," Extension IPM specialist Bruce Potter explains, "We're into managing them." Potter stresses the importance of "making sure you have a problem before you spray."

In the case of the damaging soybean aphid, Ragsdale and his team directed a research project involving 11 universities to come up with the 250-aphid threshold: If growers have 250 or fewer aphids per plant, they can leave the pests with absolutely no yield loss. Below this threshold, "you will cause more yield loss driving through your fields in July and spraying for aphids than the aphids will actually cause," Ragsdale says.

The $1.3 billion figure comes from using insecticides only when aphid populations pass the 250 threshold. To simplify the counting of aphids, Ragsdale created a user-friendly tool. His speed-scouting method leads growers through a few easy sampling steps, allowing them to make decisions in 15 minutes.

For more information on Extension resources for speed sampling the soybean aphid, visit

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