FORT WAYNE, Ind. — Pokeweed is becoming more common in Indiana fields and the problem will probably get worse before it gets better, a Purdue University weed expert said.

“Pokeweed is easily the top perennial weed problem in soybeans, and it’s getting worse every year,” said Bill Johnson, an associate professor of weed science. “I think it will get worse for another year or two.”

Pokeweed, also called pokeberry or ink berry, is a perennial with purple berries.

The increase in pokeweed is due, in part, to farmers and others underestimating how effective soil residual herbicides are on pokeweed seedlings, Johnson said.

To get pokeweed under control, farmers should consider doing treatments shortly after soybeans are harvested, he said.

“We’re learning that fall treatments are more effective,” he said. “The first treatment should be done within two or three weeks after soybeans are harvested.”

A second treatment shortly thereafter may also be necessary, he said.

Pokeweed can affect soybean stand and yield, Johnson said. It grows rapidly and its berries are poisonous. The berries can also stain the bean plants.

Purdue is making an effort to get farmers to manage weeds better, Johnson said.

“There’s a pretty substantial portion of farmers who are not making timely spray applications,” he said.

Pokeweed is also becoming more of a problem in Ohio, said Jeff Stachler, an Ohio State University extension weed specialist.

“Last year was the worst I’ve ever seen in the entire state,” Stachler said. “It’s progressively gotten worse over the last 6-8 years.”

Farmers need to have management plans in place to treat the weed for the rest of this year and next, he said.

“The best way to control pokeweed in Roundup Ready soybeans is to use the right rate of glyphosate at the right time with the right spray boom height,” he said.

Farmers should raise the nozzle boom height so the herbide effectively covers the taller pokeweed plants, Stachler said.

“You need to raise it from 12-20 inches above the tallest pokeweed depending upon the type of nozzle,” he said. “It’s better to be too high than too low, although that increases the potential for drift.”

The use of no-till is one reason for the increase in pokeweed, Stachler said.

“The passes you make over the fields when you till do a pretty good job of keeping the pokeweed in check,” he said. “Ohio has been pretty progressive in no-till, and there’s more opportunity for the pokeweed.

“Farmers are also not managing weeds as frequently in non-crop areas such as fence rows and tree lines. In general, many farmers need to pay more attention to how to manage weeds. Most people don’t understand the timing of weed management.”

Pokeweed has been a problem in just a few fields in Fayette County, southwest of Columbus in Ohio, said John Yost, the county’s extension educator for agriculture and natural resources.

“It’s not a major problem here, but we’ve seen it in a farm by farm situation,” he said. “There are a few fields that will need to be treated.”

As more farmers turn to no-till, they need to realize weed management programs will differ from those used with conventional tillage, Yost said.

“As with all weeds, the programs are different,” he said. “Farmers need to do more on the management end and fine tune their herbicide programs.

For details on treating pokeweed, go to www.btny.purdue.edu/weedscience and look for the section on weeds about halfway down in the middle of the page. Click on the section on pokeweed control.

This farm news was published in the Sept. 27, 2006 issue of Farm World, serving Indiana, Ohio, Illinois, Kentucky, Michigan and Tennessee.