EXCEPT FOR snakes, barnyardgrass is perhaps the most menacing thing in America's rice fields. Left unchecked, barnyardgrass will take an enormous bite out of your yield.

Studies show that a single barnyardgrass plant per square foot can reduce rice yields by a whopping 25 percent.

Battling barnyardgrass, as well as sprangletop, broadleaf signalgrass, and barnyardgrass resistant to propanil and Facet, can be a difficult problem for rice growers.

It takes a tough herbicide and good timing to knock out these grasses. And getting effective grass control without adjacent crop damage can be difficult, especially in areas with strict regulations to protect broadleaf crops.

One of the new entries into the grass control war is Ricestar by Aventis CropScience. After four years of testing, Arkansas and Louisiana have received a Section 18 (emergency exemption) approval for the herbicide this spring. Federal registration is expected shortly.

The makers of Ricestar say it meets the demand for solid control of tough grasses with an ample safety margin for the rice.

“Ricestar is really a good weapon for broad-spectrum grass control,” said Sam Garris, technical service representative for Aventis CropScience. “It can be your complete pre-flood grass control solution or an important part of your grass control program.”

Ricestar is recommended for use post-emergence and before flooding. Tests confirm that it's very effective at knocking out troublesome grasses in the one to three leaf stage. Researchers point to an excellent grass control record and near zero crop damage.

“The product has been about 100 percent effective on two to three leaf grasses, and we have used it in all kinds of situations with no significant rice injury problems,” said Ford Baldwin of the University of Arkansas Extension Service. Baldwin and graduate students from the university have studied the herbicide since 1998.

The active ingredient in Ricestar is fenoxaprop-P-ethyl. Technically, the product inhibits the synthesis of fatty acids in the meristem tissue of grasses. Uptake occurs within 24 hours with plant death occurring in about 14 to 21 days.

The recommended application rate is 13 to 17 ounces.

The product provides excellent control on early barnyardgrass, propanil and facet-resistant grasses, broadleaf signalgrass, sprangletop, fall panicum and johnsongrass.

“Ricestar is very good on all major grasses, but like most herbicides your timing and application must be correct,” said Andy Hurst, Ricestar product lead, Aventis CropScience. “It's really the only good post-emergence herbicide choice pre-flood for sprangletop.

Hurst noted that the product also works well in cool weather.

“Cool spring temperatures often impact herbicide effectiveness. Ricestar does very well down to 60 degrees, which is a unique benefit among postemergence herbicides,” said Hurst.