Grain bin fumigation often necessary, risky

There is some truth to the old saying “an ounce of prevention is worth a pound of cure,” but in the case of grain bins, prevention often isn’t enough.

As a first line of defense against insects and molds, farmers should vacuum or sweep empty grain bins thoroughly to remove insect debris and any remaining grain before new grain is stored. Additional steps, such as loading the grain at the appropriate moisture level and treating the empty bin and grain with EPA-approved insecticides, also prevent or discourage the development of stored grain insects.

All too often, though, it will be necessary to go a step farther and fumigate the grain to eliminate bugs, according to Kathy Flanders, an Alabama Cooperative Extension System entomologist and Auburn University associate professor of entomology and plant pathology.

But while fumigation is a common practice throughout the South, where pests and molds are a perennial threat to bins, it still carries more than its share of risks.

The most common fumigant used for on-farm grain bins is aluminum phosphide, which breaks down into phosphine gas, a highly toxic, reactive and potentially explosive gas — the reason why careful planning and monitoring are essential.

A carefully worked out fumigation plan should reflect an understanding of the chemical properties and safety issues associated with the fumigant of choice, Flanders says. The plan also should outline all the steps that should be taken before, during and after fumigation.

Without such careful planning, employers can place themselves at serious and even life-threatening risk. In fact, the law requires a fumigation plan — a fact of which many farmers may not be aware because the requirement has been in effect only a few years, Flanders says.

In mapping out their plan, producers first should consult the Applicators Manual, a multi-page guide that comprises part of the fumigant’s EPA-assigned label.

Monitoring is also critical, Flanders says.

“For safety’s sake, it’s important to monitor this gas to make sure it’s not escaping and spreading into other areas of the farm, such as the farm office, which may be located nearby,” she says.

In fact, monitoring is considered an essential safety precaution.

“Anyone who fumigates is required to keep a log of the concentration of phosphine gas at critical locations during the fumigation process,” Flanders says.

To make it easier to comply with these new laws associated with fumigation, the Wheat and Feed Grain Committee approved the use of check-off funds to buy 10 phospine gas detectors. Farmers can borrow a digital phosphine gas detector from one of five locations throughout the state.

Preparing the grain bin for treatment is another critical part of the fumigation process.

“If the grain bin can’t be sealed, fumigation will be ineffective and unsafe,” Flanders says, adding that all openings should be sealed with caulk, expandable foam or duct tape and plastic.

If the roof and eaves of the bin can’t be sealed, a plastic tarp can be placed over the surface of the grain to keep the fumigant inside the bin.

Farmers can borrow digital phosphine detectors from the following people: Chet Norris, Tennessee Valley Research and Extension Center, Belle Mina; Leonard Kuykendall, regional Extension agent, Autaugaville; Brian Gamble, Wiregrass Research and Extension Center, Headland; Gerry McGhee, chief, Atmore Fire Department, Atmore; and Doug Trantham, Trantham Farms, Alexandria.

For additional contact information for these individuals, visit:

The Alabama Cooperative Extension System’s Stored Grain Web site features a variety of printed, audio and video media on stored grain:

You also may contact your regional Extension crops agent for additional information or access the following publications off the Alabama Extension Web site: IPM Tactics for On-Farm Stored Grain, ANR-1126, Fumigating Agricultural Commodities with Phosphine, ANR-1154, IPM Stored Grains, 2008, IPM-330

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