With rice stink bug populations ramping up and limited control options available, the U.S. Environmental Protection Agency issued a Section 18 exemption for Endigo ZCX insecticide in Arkansas rice from July 14 through Oct. 15.

Endigo ZCX is currently labeled for use in soybeans, cotton and some specialty crops, but not rice. The exemption temporarily allows farmers in the nation’s top rice-growing state to use Endigo ZCX get rice stink bug populations under control.

The current threshold for rice stink bugs in flowering to milk stage rice is five stinkbugs per 10 sweeps. (University of Arkansas System Division of Agriculture)

Rice stink bugs cause yield loss by feeding on kernels, according to Nick Bateman, extension entomologist with the University of Arkansas System Division of Agriculture. This feeding also allows pathogens to enter the grain, causing discoloration which can reduce milling quality and grade.

Ineffective treatments

Prior to the exemption, growers had two options for rice stink bug control — lambda cy and Tenchu. However, Bateman said lambda cy is providing little control and Tenchu has been largely unavailable to growers.

“Control with lambda cy is a problem, especially as we move into the third and fourth week of July. We’ll be looking at about 50% control,” Bateman said. “The main reason we submitted for this Section 18 was because we essentially have one effective alternative with Tenchu, but the supply is not there to meet the demand in Arkansas.”

Bateman said this Section 18 exemption will help growers minimize damage and yield loss.

“We’re on the front end of this pressure. In general, everyone is running about one-and-a-half, two times threshold,” Bateman said. “But we have a ton of rice surrounded by barnyard grass that is chock full of rice stink bugs. There’s a big healthy population and with the way it’s built up, we’re doubling our numbers every seven days.”

Pest threshold

The current threshold for rice stink bugs in flowering to milk stage rice is five stinkbugs per 10 sweeps. Bateman said many growers are catching 10 to 15 stinkbugs per 10 sweeps.

“With the numbers we’re seeing and the numbers we’re expecting, we’re very fortunate to get Endigo in Arkansas,” Bateman said. “Our experience with this product has been good and we typically see upwards of 14 days of control.”

Bateman said the rate range for Endigo ZCX is 4.5 to 6 ounces, and he recommends 5 ounces. The exemption is limited to one application per year at 6 ounces and areas within 100 feet of the edge of the field must be kept free of flowering weeds.

Those wishing to use Endigo ZCX should review the label. Applications must be reported to the Arkansas Department of Agriculture within 10 days of the application. Applications should be reported through the online form. 

Arkansas obtained a similar exemption last year.

Use of product names does not imply endorsement.

Source: University of Arkansas System Division of Agriculture