The California Department of Pesticide Regulation (DPR) has proposed registering methyl iodide, a widely heralded replacement for methyl bromide.

“THE CALIFORNIA RESTRICTION will have an impact on how growers utilize fumigants as a whole,” said Mike Allan, Arysta global business development manager. Growers are going to have to see how Midas and other fumigants will fit.

However, it comes with draconian use restrictions as much as 400 times greater than the federal EPA requires for its use in 47 other states.

DPR Director Mary-Ann Warmerdam recommended registering the product sold under the trade name Midas. The mandatory 45-day comment period before final registration can be given ends June 14.

The registration of Midas from Arysta LifeScience comes eight years after the company first submitted a registration for the methyl bromide replacement and three years after EPA registered it. Iodomethane, the scientific name for Midas, is currently registered in the U.S., Japan and Turkey. Registration is pending internationally in New Zealand, Australia, Morocco, Mexico, Guatemala, Costa Rica, and Argentina with development in progress in many other countries.

"By law, we cannot register a pesticide unless it can be used safely," said Warmerdam. "After extensive reviews, we have determined methyl iodide can be used safely — with the extra, health-protective use restrictions we are proposing that are much stricter than those imposed anywhere else in the U.S. My department considered a wide range of scientific input and followed protocols of both U.S. EPA and the World Health Organization to develop use restrictions to prevent potentially unsafe exposures."

Arysta executives were obviously pleased DPR’s director is recommending registering Midas, but are disappointed in the onerous restrictions some believe will severely restrict the use of the product.

Nevertheless, Mike Allan, Arysta global business development manager, said the company will gear up for the fall fumigation season in California.

Allan points out that the Midas registration is the first for a methyl bromide replacement. Based on the constraints imposed on Midas, that is not good news for growers.

The buffer zones set by DPR are 200 percent to 400 percent greater than EPA requirements and have exposure levels as much as five times lower than the U.S. EPA level. These restrictions are likely to be applied to fumigant/methyl bromide replacement compounds like chloropicrin, which is next on California DPR’s list for methyl bromide replacements.

California's allowable exposure of 96 parts per billion (ppb) for licensed professionals who apply or handle methyl iodide will be half of what U.S. EPA allows. For others (those not handling or using methyl iodide), DPR will not allow exposures above 32 ppb averaged over 24 hours.

Allan said more than 15,000 acres have been treated commercially in the U.S. under the federal EPA standards with “excellent results and no incidents.

“The California restriction will have an impact on how growers utilize fumigants as a whole,” said Allan. Growers are going to have to see how Midas and other fumigants will fit.

“Fumigants are essential tools; the core of success for California agriculture,” said Allan, noting that 40 percent of all ag crops require fumigants to be productive. There are hundreds of thousands of acres affected by DPR’s fumigant registration decisions, he said.

Obviously pleased that Midas was registered after a long and controversial process, Arysta will continue to work on the registration packet to mitigate some of the proposed use restrictions.

In other states and countries where Midas was registered earlier, Arysta has conducted extensive stewardship and training programs for users of the product. That will be put in place in California as well for planned commercial Midas launch later this year, said Allan.

“This announcement is a step in the right direction for California,” said Bill Lewis, president and CEO of Arysta LifeScience North America.

Midas is comprised of a formulated blend of iodomethane and chloropicrin and is effective at more than 40 percent lower use rates compared to methyl bromide, according to the company.

Midas does not deplete the earth’s ozone layer. A year ago, EPA awarded Arysta and several researchers from universities and the Agricultural Research Service of the U.S. Department of Agriculture the prestigious Ozone Layer Protection Award in recognition of the non-ozone depleting characteristics of Midas.

“This is a step in the right direction for the agricultural community and the environment,” said Royce Schulte, U.S. product manager for fumigants for Arysta LifeScience. “Growers in other areas of the country have been using Midas for more than two years. It’s time that California growers have access to this important tool.”

Warmerdam said DPR scientists examined more than 175 studies on the potential health and environmental effects of methyl iodide. They paid particular attention to potential exposures of people who live, work or spend time in areas close to fields where methyl iodide might be used.

DPR also will make methyl iodide a California-restricted material, meaning users will be required to have special training and a permit from the county agricultural commissioner, who can impose added use controls tailored to the application site.

It can be applied by drip irrigation under a special protective tarp or injected into the soil using a tractor that automatically places a tarp over the ground after application.

The major uses of methyl bromide in California are to treat soil where strawberries, nursery plants and nut trees are to be planted. Since U.S. EPA considers methyl iodide a feasible alternative to methyl bromide, the federal agency is expected to approve far fewer exemptions for methyl bromide in California.

Here are some specifics on the proposed California Midas registration:

• Lower allowable exposure levels: 96 parts per billion (ppb) for licensed professionals applying or handling methyl iodide (half of what U.S. EPA allows). For others (those not using methyl iodide), DPR will not allow exposures above 32 parts per billion averaged over 24 hours. This is five times lower than the U.S. EPA level.

• Like U.S. EPA, California applicators must be certified or under the direct supervision of a certified person. However, DPR also requires a site-specific permit from the county agricultural commissioner, who can impose extra use restrictions tailored to the application site. EPA requires no permit.

• Larger buffer zones of 100 to 2,500 feet around all applications, depending on application method and rate, and treated acreage. EPA’s buffer zones are smaller, ranging from 25 to 500 feet.

• Bigger minimum buffer zones around schools, hospitals, nursing homes, day care centers, and similar sites, a minimum buffer zone of one-half mile. EPA’s minimum buffer zone is smaller at one-quarter mile.

• Prohibit standard tarps. Only virtually impermeable film (VIF) tarps allowed. This material contains a gas-impermeable layer designed to suppress the movement of fumigants into the air. EPA allows both standard and VIF tarps.

• Fewer acres can be treated at once: A maximum of 20 to 30 acres, depending on the method. EPA acreage limit is higher, 40 acres regardless of application method.

• Prohibit night applications, which typically result in higher levels of fumigant in the still air. EPA has no limits on time of application.

• Reduced application rates of 75 to 125 pounds an acre, depending on application method and crop. EPA’s maximum rate is higher, 175 pounds an acre.

• Stricter groundwater restrictions such as buffer zones around wellheads and application limits in vulnerable areas. EPA’s groundwater protections are more limited.

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