By KEVIN WALKER
Michigan Correspondent

LAWRENCE, Kan. — Several articles published in an industry magazine recently bear witness to the problems producers continue to have finding and using effective herbicides for their specialty crops.

Weed Technology, the magazine of the Weed Science Society of America, has just published, Industry Views of Minor Crop Weed Control by Roger Gast, a research leader at Dow AgroSciences.
This article, along with several others, explains in some detail the problems industry has when it comes to development of these herbicides.

Gast states the number of new herbicides that can be used on specialty crops is diminishing, for several reasons. One is consolidation in the industry. The reason for this is most herbicides that end up being used on specialty crops are originally developed for use on major crops, since the cost of developing an herbicide is too great to be profitable if it’s targeted for a minor crop only.

“New herbicide discovery and development efforts are almost exclusively directed towards major crop market uses due to the rigorous financial hurdles required of pesticide industry corporations,” Gast stated. “Minor crops are rarely considered during the discovery and initial development phase, but are considered at later stages of the product life cycle, depending on various factors.

“Most existing minor crops uses are typically the result of serendipitous selectivity uncovered after initial active ingredient registration.”

Fewer companies doing this sort of development means fewer new herbicides which might be appropriate for use on minor crops. According to the article, between 1980-2001 an average of six new conventional herbicides were launched annually, while that number dropped to only two a year between 2002-06.

Another factor is the development of herbicide resistant crops (HRC), which have made conventional herbicides less profitable. Corn, soybean, cotton and canola crops have been especially affected by the development of HRCs, Gast wrote. As a result, the amount of “discovery research” for these crops has likely been reduced or eliminated by pesticide companies.

Gast also cites flat sales due to a maturing industry, increased competition with generic herbicides as patents expire and increasing costs to register and re-register herbicides. There’s also liability risk on the part of companies that develop these herbicides.

“Additionally, many minor crops have the distinction of having a relatively high value, increasing the liability risk for the potential registrant in the event crop yield losses are incurred,” Gast states.
Additional barriers include some unique costs to development of herbicides because of the need for field trials to evaluate crop selectivity. U.S. Environmental Protection Agency (EPA) regulations have also made it more difficult and expensive to develop new herbicides.

“Regulations outlined in the Food Quality Protection Act (EPA 1996) concerning aggregate risk also have impacted minor crop herbicide registrations,” Gast wrote. “Aggregate risk takes into consideration both dietary and non-dietary exposure risks from a given pesticide.
“Each additional use of the pesticide must be weighed for its effect on the allowed aggregate exposure amount. Sometimes the addition to aggregate risk from minor crop use is viewed as excessive or disproportionately high.”

This creates another disincentive in development of chemistries for use with minor crops. So, what’s to be done?

Gast cites a number of tactics to help companies achieve a profit on development of herbicides for minor crops, including extending patent protection and other “date protection mechanisms,” reducing fees to register and re-register a chemistry and streamlining some EPA regulations that impact the use of herbicides on minor crops.
The single biggest barrier to the development of these herbicides is liability risk, according to Gast. This is because the value of minor crops is much larger per acre than it is for major crops, yet on the profit side of the equation, the benefit to a company is relatively small.

Gast suggests that the Specific Off-Label Approval (SOLA) concept be implemented here in the United States. It is currently used in Britain. SOLA provides blanket legal protection to the pesticide company in the event of a minor crop failure when its herbicide is used.

A potential user of an herbicide for an off-label use would be able to use it only after being told, via a website, that the company can’t be held responsible for any crop loss.

In this way, the grower would be able to use the herbicide but the pesticide company would also be immune from any potential lawsuits. Gast warns that in order for this to happen, growers’ groups and others would have to be on board.