Mississippi catfish producers have been given the green light by the Environmental Protection Agency to use the algaecide diuron again this year.

The Section 18 emergency exemption label granted April 20 will allow producers to treat the blue-green algae that has been linked to problems with off-flavor fish.

The product is needed, producers say, to combat the persistent problem with off-flavor catfish because diuron is effective in reducing or eliminating the blue-green algae attributed to the off-flavor of catfish harvested from affected ponds.

The Section 18 label remains in effect from April 20 to Nov. 30, 2003, and applies to Diuron 80W, manufactured by Drexel Chemical Co., and Nautilus Aquatic Herbicide, manufactured by Griffin LLC.

This is the sixth year a Section 18 permit has been requested on behalf of Mississippi producers. Producers were granted emergency exemptions for the algaecide in 2000, 2001, and 2002.

According to the exemption, the diuron products may be applied in or on commercial levee-contained catfish ponds in Mississippi by pouring a pre-mixed slurry from a bucket directly into the pond on the outflow side of the operating aerator. The treatment may be applied at a rate of 0.5 ounce of product or 0.4 ounce active ingredient per acre foot.

Application can be made every seven days, but may not exceed nine applications per year or more than 0.225 pound of active ingredient diuron per acre foot per year.

A maximum of 67,200 pounds of the active ingredient in Mississippi may be treated under the Section 18 exemption.

In addition, the label advises producers to avoid any exposure of pond water treated with diuron on the federally-listed endangered plant species of Price's Potato Bean or Pondberry.

For more information about the Section 18 label for diuron, contact the Mississippi Bureau of Plant Industry at 662-325-3390.