FURADAN WILL BE BANNED AFTER 1998, so alternate pesticides are being tested for control of rice water weevils under the leadership of Dr. M.O. (Mo) Way, entomologist at Texas A&M's Agrcultural Research and Extension Center, Beaumont. Furadan was banned because its misuse has caused bird kills.

FOR IMMEDIATE RELEASE September, 1997

BEAUMONT CENTER TESTS ALTERNATIVES TO FURADAN TO CONTROL RICE WATER WEEVIL

Contact: Dr. Jim Stansel (409 752-3045) or Dr. M.O. Way (409 752-2741)

For photos: Dr. Thomas R. Hargrove (409 762-2763)

By Tom Hargrove

BEAUMONT—Furadan has long been the most effective pesticide for control of water weevils, the number one insect pest of rice in Texas. But the U.S. Environmental Protection Agency has banned use of the insecticide, whose chemical name is carbofuran, after 1998 because its misuse has resulted in bird kills.

"We're evaluating pesticides to replace Furadan," says Dr. M.O. (Mo) Way, entomologist at the Texas A&M University Agricultural Research and Extension Center at Beaumont.

Karate, Icon, and Dimilin—the main pesticides being tested--all perform well, when applied at the right time and rate, Way says.

"Texas rice farmers may possibly be able to use all three replacement insecticides next year," the entomologist speculates. "Karate recently received a full federal label. Applications for Icon and Dimilin are being submitted to EPA for review."

Karate controls water weevils when applied soon after the permanent flood. Studies this year also suggest that Karate may also be effective when applied several days before the permanent flood. "That means farmers may be able to mix a preflood herbicide with Karate," Way says. "We'll evaluate the possibility in further studies."

Karate controlled water weevils as well as Furadan when applied 3, or even 6, days before permanent flooding in Beaumont studies.

Icon, or fipronil, is basically a preventive, or prophylactic treatment, the entomologist says. Low rates of Icon controlled 93 to 94% of the water weevils when incorporated into the soil before planting or applied as a seed treatment in a 12-acre study at Beaumont. Furadan gave 70% control.

Dimilin performed as well as Furadan when applied 2 days after permanent flooding at the Beaumont Center's research site at Eagle Lake. "It's critical that Dimilin go on soon after the field is flooded," Way stresses.

"Don't compare the new insecticides in these experiments," Way warns. "Each test was different, and rice water weevil populations varied."

Water weevils move into fields, as 1/8th-inch brown beetles, from overwintering habitats as fields are flushed and flooded. They seem attracted to deep water and thin plant stands. Adult feeding leaves slit-like scars on the rice leaves. High levels of egg-laying females soon after flooding result in high populations of larvae, or root maggots.

"The root maggots can survive only in saturated soils," Way says. "They are white, and feed on the roots of young plants. Root maggots grow to about a third of an inch long before pupating in mud cells attached to the roots."

Half a century ago, farmers could control the rice water weevil only by draining rice fields to dry the soil. Draining still works, if there is no rain, but may be prohibitively expensive.

The Beaumont Center also studies control of other rice and soybean insects, and of blackbirds. For more information, contact Dr. Mo Way at 409 752-2741 or 866-7232.