Mo Way recommends discretion as the better part of any plan to treat grasshopper infestation in Texas rice fields.
Even though grasshopper numbers have been high this summer, Way cautions against treatments.
“I’ve never seen a field that needed to be treated for grasshoppers,” Way said during a recent field day at the Texas AgriLife Research and Extension Center in Beaumont. “Short head grasshoppers have been more damaging this year,” Way, professor of entomology, said. “But we need to see 20 percent defoliation to justify control measures. I’ve still not seen fields that needed treatment.”
He said ample materials are available for treatment.
“It’s been a bad year for water weevil, too,” he said. “But we have good products to control it as well. Seed treatments and pyrethroids are effective.”
He said stalk borers may be good targets for seed treatment products. Tests in 2009 with Dermacor X-100 showed good results in the main crop and carryover into the ratoon crop. “We recorded a 550 pound per acre yield increase in the main crop versus the untreated check,” Way said. “The ratoon crop showed better than a 1,000 pound per acre increase versus the check.”
Economics and environment are both important goals in the center’s research efforts.
“Rice research in 2010 emphasizes novel seed treatments for control of rice water weevil, chinch bug, aphids, thrips, fall armyworm, South American rice miner and stalk borers,” Way said
He said a key goal is to refine treatment rates in relation to seeding rates. “For economic and environmental purposes, our rice farmers should apply the least amount of pesticide and still obtain good control over the pests,” he said.
Planting hybrid rice may help. “Hybrids are planted at about 25 pounds per acre, while conventional inbred varieties are planted at about 60 pounds to 90 pounds per acre. If a given amount of insecticide is applied to 100 pounds of seed, then lower seeding rates will result in less insecticide applied versus higher seeding rates.”
Determining how the change affects seed treatment efficacy “is a good question to answer for all new seed treatments,” Way said.
Efforts this year include tests with Dermacor X-100, CruiserMaxx and Nipsit INSIDE.
Way also noted that recent studies indicate that Texas populations of rice stink bugs are harder to kill with Karate Z than are populations in other states. Data from the studies were submitted to the Texas Department of Agriculture and the U.S. EPA to help obtain an Emergency Exemption Section 18 for Tenchu 20SF. That exemption was recently approved.