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Scout Now for Black Cutworm

TAGS: USDA
Scout Now for Black Cutworm
There will be cutworms in some fields.

Volunteers who capture moths and report data to John Obermeyer and Christian Krupke at Purdue University had a so-so year in terms of finding moths. That's like a glass half-full. They didn't record catches anyways near what was reported during the last week of trapping in 2006, but they found more than one year ago. Obermeyer terms the catches as 'not all that impressive.'

However, that doesn't mean black cutworms won't show up in your area. Often, they should up in patches within fields. They hatch based upon heat unit accumulation. Scouting is definitely recommended to see if black cutworms show up ion significant numbers in any of your fields.

Fields that shouldn't show significant black cutworm feeding are those where the corn contains the Herculex trait. Duane Canfield, marketing specialist for Dow AgroSciences, says farmers who planted Herculex hybrids have built-in protection against black cutworm. Only hybrids containing the Herculex trait have this in-plant protection from black cutworm.

That also includes fields planted to SmartStax hybrids, since those hybrids contain the Herculex trait. SmartStax hybrids were only distributed in limited supply this year. Estimates are that about two million acres of SmartStax corn were planted or will be planted yet in the U.S. this year.

Still, Dow AgroSciences officials urge farmers who planted Herculex hybrids to scout fields. They note it's still important to scout fields so they understand all the insect pressure fields face, not that from black cutworm.

Plus, even in fields protected by Herculex, insects must get a taste of the tissue to die. Where black cutworms are bigger, they are harder to kill, notes Travis Belt, a Mycogen Seeds customer agronomist. "It will take more feeding on Herculex corn to have an effect on the larvae, which can lead to more damage."

Entomologists say that some fields which don't have built-in black cutworm protection have been treated already. Consult the Purdue University Corn & Soybean Field Guide for help on deciding when threshold levels of black cutworm indicate that treatment should pay for itself, or return profit, vs. not treating.

Purdue entomologists also caution that when scouting, be careful to distinguish between dingy cutworms and black cutworms. Dingy cutworms may feed on leaves, but typically don't cut plants. The two can be difficult to tell apart. The Field Guide has pictures which should also make it easier to distinguish one from the other. If you're making treatment decisions on black cutworm, you want to make sure you're dealing with black cutworm, not dingy cutworm.

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