This season you have the luxury of having two weevil-control products that may help reduce the need for scouting and take much of the guesswork out of application timing. In trading for convenience, though, you may be committing to treat without knowing whether weevils are going to cause problems.

The two products--Icon seed treatment and Karate--have labels that allow growers to apply the product ahead of the permanent flood and the time when weevils typically migrate into the field. Icon is not registered for use in California, and a similar formulation of Karate--Warrior T--is marketed in California.

Karate Z can also be applied after the permanent flood, similar to Dimilin, the third registered weevil-control product.

If you choose to treat after applying the permanent flood, Extension entomologist recommend scouting for feeding scars and adults beginning shortly after rice emergence.

This will be the second season for Icon FS, a seed treatment from Aventis CropScience, formerly known as Rhone Poulenc Ag Co. Although the product provides as good or better control than the old industry standard, Furadan, growers must decide before planting whether they want to use it. (Furadan, the brand name for carbofuran, is no longer registered for use on rice.)

This is a departure from the past, when they scouted for the weevil and only applied Furadan when adult feeding scars or larvae counts from core samples exceeded treatment thresholds. Growers also must have the seed treated with Icon FS at an approved facility.

Data from Texas show Karate can be tankmixed with herbicides and applied immediately before the permanent flood. This should help save an additional aerial application fee, which runs about $4 per acre.

Karate, a pyrethroid from Zeneca Ag Products, kills only the adult weevils, not the eggs or larvae. To be most effective, it should be applied just before the females lay eggs.

Dimilin, an ovicide from Uniroyal Chemical Co., kills only weevil eggs, not adults or larvae. The product should be applied to fields only after permanent flood is established and adult are present, according to Louisiana State University Ag Center recommendations.

Based on three years of research, Texas A&M Associate Entomology Professor Mo Way says growers can apply Karate up to seven days before permanent flood and still obtain good control. Any earlier than that and you begin to lose effectiveness.

If you opt for this program, you=ll no longer need to scout for the first signs of adult feeding on leaves and then order an aerial application. And like Icon FS, if you choose the earlier Karate timing, you may be committing to treatment before you know you have a real weevil problem.

AIt=s still a preventative, but there are some things they can go by,@ Way says. Thin stands having a past history of weevil problems or putting the flood on relatively early in relationship to emergence--four weeks or earlier--seem to worsen weevil problems. Medium-grain varieties also are more susceptible to weevil damage

Conversely, growers who wait to apply permanent flood until five to six weeks or later after rice emergence have fewer worries about weevil problems, Way says. Weather also is a factor. Even if growers leave the flood off, spring rains, potholes in fields that hold water or moist soil can provide conditions that attract female weevils seeking places to lay eggs.

Way began his research after talking to growers who claimed good results putting Karate out with herbicides pre-permanent flood.

AWe were hearing from consultants and some of the farmers using Karate to control fall armyworms, and they felt they were also getting control of rice water weevil,@ Way says. AThey were putting it close to the flood and got good control.@

So Way started moving the applications back, first three days before permanent flood, then six days and still obtained good weevil control.

The past season, he looked four different timings--immediately before permanent flood and seven, 14 and 21 days before permanent flood. AOnce you go earlier than that seven days before permanent flood, your control really starts to decrease,@ Way says. AOur control was as good as the post-flood applications up to about a week before permanent flood. We have studied tankmixes with various herbicides and haven=t had any problems.

Mike Stout, an assistant entomology professor with LSU=s Ag Center in Baton Route, has only studied earlier Karate applications for one year and doesn=t have as much data as Way.

He only recommends a pre-permanent flood Karate application if adult weevils are present. Nevertheless, some growers in Louisiana are applying the product early.

AWhether I recommend it or not, growers are already tankmixing herbicides with Karate,@ Stout says. AFrom what I hear, they do fine with it.@

In southern Louisiana, growers more than likely will need to make a second Karate application, Stout says.

For growers opting to treat after permanent flood, LSU=s Ag Center recommends beginning scouting any time after rice emergence.

Both Way and Stout say they are uncomfortable with current treatment threshold levels because of several unknowns.

Currently, the Texas A&M Rice Production Guidelines recommend treatment if you=re scouting and find 50 percent of the sampled plants with weevil feeding scars on the youngest leaf.

In three years of research, Way says he hasn=t found a direct correlation between the number of adults found in the field, number of feeding scars and the number of larvae found later feeding on roots.

In Mississippi, Rice Extension Specialist Joe Street recommends scouting and treating if you find one weevil per square foot.