South Carolina cotton growers have a new weapon to combat pyrethroid resistant bollworms as well as tobacco budworms and beet armyworms.

The U.S. Environmental Protection Agency has granted Section 18 approval of DuPont Steward insecticide in South Carolina for control of cotton bollworm, tobacco budworm and beet armyworm in cotton. The Section 18 exemption allows cotton growers in the state to use Steward between July 27 and Oct. 31, 2000.

"When we applied for the Section 18 exemption, we assumed we would have problems with bollworms resistant to pyrethroids," says Clemson University Extension Entomologist Mitchel Roof. "Through the middle of August we had not had as much of a problem as we anticipated. But, beet armyworms could break loose at any time. In late August and early September, armyworms can damage later planted cotton. In a situation where a pyrethroid is just not doing the job, I see Steward fitting in."

He also points out that Steward insecticide is considered to protect most beneficial insects. Some tests show the product to be effective in controlling plantbugs.

Roof says the 1.25 pound suspension concentrate formulation of Steward should be applied at a rate of 11.3 ounces per acre for bollworms and budworms and 9.2 ounces to 11.3 ounces per acre for beet armyworms. There is a 12 hour re-entry period.

According to information released by DuPont, the active ingredient in Steward, indoxacarb, is a new class of insecticide chemistry with a novel mode of action. This unique mode of action means Steward is an effective integrated pest management tool. Because it has a favorable environmental/ecological profile, it is easy on most beneficial predators and parasites, minimizing aphid and mite population flare-ups.

At labeled rates, Steward can provide from five to seven days of residual protection of treated cotton, depending on the insect, population pressure and crop/environmental conditions.

"We are very pleased that the EPA has approved DuPont Steward insecticide for specific exemption use in the state of South Carolina, since we believe that cotton consultants and growers will find this product to be effective when cotton bollworm, tobacco budworm and beet armyworm populations reach economic thresholds," says Lynn Loughary, product manager for DuPont Steward.