Last month’s column (http://westernfarmpress.com/alfalfa/alfalfa-restrictions-0113/index.html) ended with a few words about the Federal EPA’s pending restrictions for chlorypyrifos, plus malathion and diazinon. The agency’s action is linked to a Biological Opinion (BiOp) that the National Marine Fisheries Service (NMFS) designed to protect endangered and threatened salmon and steelhead.

The use limitations are the result of measures outlined in NMFS’s November, 2008 BiOp, a biological opinion that has been controversial and difficult to swallow for growers who will be affected in California, Oregon, Idaho and Washington. The NMFS BiOp indicated that a standard buffer of 500 feet for ground applications and 1,000 feet for aerial application of “salmonid” habitat is needed to protect these species. They also indicated that a 20-foot vegetative buffer needs to be established next to salmon waters, a recommendation the EPA will substitute with “variable buffers.”

According to an e-mail from the EPA, the agency intends to impose “variable buffers” depending on application rate, spray droplet size, and water body size. Buffers will range from 100 to 1,000 feet depending on these factors and will account for runoff in addition to spray drift. Therefore EPA doesn’t plan to require an additional 20-foot vegetative buffer. (Buffers and other limitations can be found in a Sept. 10, 2009, letter to James H. Lecky, director, Office of Protected Resources, NMFS, epa.gov/espp/litstatus/wtc/nmfs-signedresponse.pdf.)

In its letter to EPA, CAFA noted that “chlorpyrifos (Lorsban/Lock-On) is the most widely used insecticide in alfalfa. And, California has a strict water monitoring program that measures pesticide residues in parts per trillion. Restrictions recommended by the NMFS would have the effect of prohibiting usage in affected areas.” A key point in CAFA’s letter was the potential problem when restrictions prohibit growers from using the insecticide.

For example, growers would lose a valuable component of IPM and resistance management programs, leading to a lower return on investment. The University of California lists chlorpyrifos as having a moderate effect on beneficial insects. It is well documented that the chemical class frequently used as a substitute is much more disruptive. In addition, alfalfa hosts high numbers of beneficial insects that migrate to adjacent crops, a benefit that enhances IPM programs over a wider area.

Around the time that we were contacting the EPA, Forrest Laws’ Western Farm Press column (http://westernfarmpress.com/news/laws-column-1210/index.html) had an interesting development on another pesticide, atrazine, “one of the most successful herbicides ever.” Like chlorpyrifos, atrazine has been scrutinized by the EPA and regulatory agencies in other countries. Nonetheless, the EPA is planning another review even though the herbicide just completed a multi-year regulatory study that concluded it is “not likely to cause cancer in humans” and doesn’t affect reproductive development of frogs and other amphibians. Laws’ contacts, “veteran EPA watchers” said that the impetus for the review is coming from the Natural Resources Defense Council. But he added, other farm chemical manufacturers maintain that they have “been victimized by the shift in direction at EPA.”

Chlorpyrifos has become a major target of environmental groups who are trying to take it off the market. Fortunately, Dow AgroSciences has stated its determination to defend the insecticide. Based on recent developments, it will need to be resolute as environmental groups get an even bigger voice in shaping regulatory policies.