On the federal level, the Environmental Protection Agency recently completed a re-registration process for common fumigants in almonds, including methyl bromide, chloropicrin and metam sodium. As of January 2011, there are new label requirements that include the development of a fumigant management plan, new safeguards for worker and applicator protection, and new staffing requirements. Additional restrictions will be placed on those labels in early 2012 to include more extensive buffer zones or tarps, restrictions on use in sensitive sites such as schools and prisons, and warning requirements for neighbors within a certain range of application site.

With these new labels, it is important growers read the label and associated booklets carefully before making an application.

Another compound, methyl iodide, which is already approved at the federal level, has been proposed for approval in California, although various lawsuits and environmental opposition are jeopardizing the future state registration of this promising compound.

In the San Joaquin Valley, VOC rules enacted in 2009 have imposed severe limitations on the rate, timing and application method of common fumigants during the ozone period from May 1 through Oct. 30.

These restrictions can make fumigation applications less efficacious and often more expensive due to required mitigation measures. For instance, the VOC window pushes applications into the fall and winter months when soils are less likely to be dry and warm— preferred conditions for optimum efficacy. Methyl bromide (which performs better than other available compounds under cooler, moist conditions) can be used either alone or in combination with Pic from May to October. However, the new VOC rules require that methyl bromide be applied during that window using an expensive high density polyethylene (HDPE) tarp.

Further complicating this regulatory maze, these VOC requirements do not necessarily correspond with the EPA requirements enacted under the new labels. As mentioned above, your local ag commissioner is a good place to start to help sort out what restrictions exist and which compounds are available to you in your area at the time you plan to apply. For the latest reports on Almond Board–funded research projects on fumigation, go to AlmondBoard.com/farmpress17.