Broadleaf weeds and sedges have become more problematic in recent years in North Louisiana rice fields, probably because of the increased use of Command and other herbicides with limited broadleaf and sedge activity, according to Dr. Bill Williams, an LSU AgCenter weed management specialist at its Scott Research, Extension and Education Center.

"We need to get back to a propanil-based weed program for early season weed control," Williams said.

Rice yields are declining in fields where broadleaf weeds get out of control, he said.

Before Command, farmers sprayed propanil at the 1- to 2-leaf stage and then followed up with another application.

Delaying broadleaf weed control leads to larger and more difficult weeds to manage. Larger plants are not eliminated, and weed populations increase, Williams explained.

By waiting until weeds are bigger, traditional broadleaf weed-control programs like propanil plus Londax are less effective, he said.

The LSU AgCenter scientist is testing an experimental herbicide from Valent that has excellent residual activity on broadleaf weeds.

"We’re pretty excited about it, but it’s a couple of years away," Williams said.

Texas weed also is getting a lot of attention as a major weed problem in North Louisiana, according to Williams.

The chemical Grandstand is effective against it, but it has drawbacks. "Our producers don’t like to use it because of its potential for injury to rice," he explained.

Williams said resistant weeds have the possibility of becoming a major problem. Barnyard grass is a headache, and water hemp is now a problem in cotton and could become one in rice. –Bruce Schultz