A new chemical for stink bug control on rice has been given federal approval on a limited basis for Louisiana farmers.

The chemical Tenchu, made by Mitsui, will be available to treat up to 50,000 acres in Louisiana.

An alternative chemical to pyrethroids will help farmers control the pest, said Natalie Hummel, LSU AgCenter entomologist. “We are starting to see signs of resistance developing to pyrethroids.”

Hummel anticipates north Louisiana fields will be treated more than those in south Louisiana. “Most of the crop in south Louisiana has passed the point where it would be susceptible to stink bug damage.”

Stink bugs can reduce yields if the insect infests a field when the rice is at either the flowering or milk stage. The insect can affect grain quality if it attacks the grain in the soft dough stage. Once the grain reaches the hard dough stage, stink bugs will cause little damage to a crop.

South Louisiana has not had much stink bug pressure this year, but some north Louisiana farmers have reported severe damage, Hummel said.

Other states have found that Tenchu has a residual control of roughly 7 to 10 days. “We are conducting an evaluation to see if that’s true in Louisiana.”

A milling analysis will be done to compare rice treated with Tenchu with rice treated with pyrethroid insecticides to determine if either chemical has an advantage, Hummel said. The studies are being done with a grant from the Southern Region Integrated Pest Management Center.