MANHATTAN, Kan. – It’s that time of year when tractors are rumbling through fields, green shoots are emerging – and herbicide sales people are calling. But one Kansas State University scientist has this message: Be careful.

"All farmers are interested in new inexpensive ways to control weeds, especially troublesome noxious weeds such as field bindweed and johnsongrass," said Dallas Peterson, weed science specialist with K-State Research and Extension. "However, farmers need to be wary of herbicides sold over the telephone because they usually are not a good buy."

Similar precautions should be taken when considering buying over the Internet, he said.

Every winter and spring, farmers receive calls from sales people – often from outside the state – trying to sell herbicides.

"The names of the bargain products and the companies selling the chemicals change from season to season, but the game stays the same," Peterson said.

The sales representatives often claim their product is similar to Roundup or some other well-known brand, gives good long-term noxious weed control, has no soil residue, and is safe to use.

"By referring to a noxious weed and by comparing the product to a recognizable herbicide, the caller can get immediate grower interest," he said.

"I had a landowner call me this morning, saying he’d received a call from a salesperson making some pretty outrageous claims," said Cowley County agricultural Extension agent, Chris Baker.

Peterson said the herbicides may control weeds, but that they are generally very expensive on a per acre basis, and may not perform as claimed. They are often priced similarly to other herbicides on a per gallon basis, but contain a dilute concentration of chemical such as 2,4-D, diquat, prometon, prometryn, or bromacil herbicides, plus a high concentration of petroleum oil.

"Rates are often given in confusing units such as gallons of product per 1,000 square feet, or ‘one gallon will treat a 4-foot-wide strip one mile long’," he said. "That may sound like a large area, but is actually just a fraction of an acre."

Peterson encouraged growers to obtain as much information as possible about the product, the company and the salesperson when they receive calls promoting unfamiliar products. Questions they should ask include:

* What’s the name of the active ingredient?

* What’s the concentration and formulation of the product?

* What’s the recommended application rate per acre?

* What does the product cost per acre?

* Is the product registered with the Kansas Department of Agriculture (KDA) for sale within the state?

"All pesticides sold for use in Kansas must be registered with the Kansas Department of Agriculture," Peterson explained. "Also, make sure to get the company and sales representative’s names, telephone numbers, and addresses. Generally, a request for this information will terminate the conversation very quickly.

"If the deal sounds suspicious, call the KDA or consult with your local county Extension agent for additional information. Generally, the best policy when buying weed control materials is to purchase products of known quality from a reputable dealer," he added.