Southern researchers target rice pests

Southern rice farmers won't be using Orthene on rice stink bugs this year. M.O. Way, Texas A&M entomologist based in Beaumont, brought that news to the Rice Research Station field day in Crowley, La.

In mid-February a package was submitted to the EPA requesting a regional Section 18 for Orthene on rice stink bugs.

“That included all the states in the South — Louisiana, Arkansas, Missouri, Mississippi and Texas. It was sponsored and had full support from the USA Rice Federation and U.S. Rice Producers Association.”

After a lengthy wait, the EPA held a conference call on its verdict the week of June 19.

“I was hopeful (going in), but about 10 minutes into the call, I could see where it was going,” said Way. “The Louisiana Department of Agriculture and Forestry and the Texas Department of Agriculture really went to bat for the submission. They reviewed the package for a long time so we at least got (the EPA's) attention.

“We tried this before in Texas. As soon as we submitted (the package), it was shut down. (This time), I thought we were close to approval.

“Basically, we came up with a figure that said if Orthene were registered it would provide a $46-per-acre benefit. Less pesticide would be used in the long run, and we'd also increase our head rice yield and decrease peck.”

On the environmental side, researchers estimated that by using Orthene the insecticide load would drop by over 300 pounds active ingredient annually in the southern rice-growing region. Such findings showed a “win/win” for both the rice industry and environment, said Way.

EPA came up with three problems:

  • Dietary residue data. “We have no control over that.”

  • Orthene is an organophosphate. The “main factor” for the refusal was that the EPA “doesn't want to register any new organophosphates.”

  • Economics. “They had problems with our economic analysis.”

Still, after the conference call, “I received a call from EPA. They encouraged us to apply again next year. If we can beef up the package and make it better…it (could work). This may be one of those things where, if you knock on the door enough times, it'll be opened.”

To control rice stink bugs, Way has looked at a lot of compounds over the years, and “Orthene has always proven best. We estimate that, conservatively, one application of Orthene equals two applications of methyl.”

Way also touched on stem borers. While the Mexican rice borer has been found as far east as Jefferson County, Texas (where Beaumont is located), the pest still hasn't been found in Louisiana.

“As for control tactics, the later you plant the worse the problem. That's true for both Mexican rice borers and sugarcane borers. In general, the hybrids are the least susceptible to stem borers.”

For management, there are three insecticides available: Prolex, Mustang Max and Karate Z. All are labeled and the best timing for them is at 1-inch to 2-inch panicle followed by a second application at late boot/early heading.

“One application is better than none and two applications are better than one. We're finding the Mexican rice borer will infest plants higher up. Many times, they'll be right below the panicle…The sugarcane borer causes more infection sites lower on the plants.”

Louisiana pests

There are two major rice pests in Louisiana. The rice water weevil is an early-season tormenter while the rice stink bug shows up late-season. Mike Stout said much of the entomology program at the Crowley station is aimed at developing cost-effective management programs for those pests.

“In addition to those two, we also have a number of minor pests,” said Stout, an LSU AgCenter entomologist. “Out of the past few years, this is the year when we've had the most problems with minor pests. And by ‘minor pests’ I mean those that aren't problems every year — fall armyworms, chinch bugs or the South American rice miner. We're probably having trouble with the ‘minor’ pests because of the dry weather.”

As trailers full of attendees looked on, Stout said a test directly behind him concerned granular and foliar insecticides against the rice water weevil. Most of the insecticides are postflood.

“It's interesting that for many years there wasn't much interest by chemical companies for testing alternative or new products against the rice water weevil. But for the past couple of years (there's been) a resurgence in weevil insecticide research.”

Next to that test was a series of small plots looking at plant resistance to the weevils.

“Specifically, we're looking at tolerance. We're interested in the type of plant traits that either allow the plant to recover or withstand damage from the weevil.”

Researchers are also studying the influence of cultural practices on the pest. Cultural practices can have a large impact on weevils.

“In the past, I've spoken on delayed flooding for weevil management. In this test, we're looking at seeding rates and the influence they have not only on the severity of weevil infestations but also on the ability of rice plants to withstand and tolerate weevil injury.”

Hide comments


  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.