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Fumigating grain beetles

Accessing and using fumigants for grain beetle control in stored grain has become more complex, says an Alberta Agriculture and Rural Development (ARD) specialist.

"Obtaining the fumigant, whether Phostoxin, Gastoxin or Weevilcide, is only half the job, as requirements for application and record keeping have changed," says Harry Brook, crop specialist, ARD, Stettler. "Products containing phosphine are highly toxic and rules have been recently updated to reduce the risk to both the applicators and the public."

Phostoxin was reviewed by the federal Pest Management Regulatory Agency (PMRA) in 2004 with changes recommended for its use and handling. Phostoxin is used extensively in agriculture to control grain beetles found in stored grain, both on farm and at the grain elevator. The PMRA has been inspecting users of Phostoxin to ensure they are complying with the new requirements for its use.

"If you have to use phostoxin either for stored grain pests or rodent control, you must have a valid Farmer Pesticide Certificate with the proper endorsement to purchase and use phostoxin. These certificates can be obtained by studying and taking the Farmer Pesticide Certificate exams. Any certificates without an expiry date are no longer valid as they were issued prior to 2008. There is one for the base course, then endorsements for stored grain pests and vertebrate pests (gopher control). Most producers can contact their local agriculture fieldman in the county office for details. These certificates are good for five years; after that, producers have to attend a refresher course to renew for an additional five years."

Once you have your endorsement to use phostoxin, and have the beetle in your grain bins or have Richardson ground squirrel problems (registered for control only in Alberta), you must have the right equipment, says Brook.

"Under PMRA rules you must use an approved air purifying, full face, gas mask with a chin style, front or back mounted canister approved for phosphine whenever handling this pesticide. Contact a local safety store for equipment."

There are also some major restrictions for use of phostoxin. A main one prohibits its use within 500 meters of a residential area.

"As well, treated bins should be aerated prior to re-entry," says Brook. "Treated areas must have posted placards. Warning placards must be placed on every possible entrance to the fumigation site. It is not legal to move treated products in trucks, trailers, containers, vans, etc., over public roads or highways until they have been aerated and the warning placards removed."

In addition to this, the user of phostoxin must have a fumigation management plan in place. "This is to ensure a safe and effective fumigation. The plan must address characterization of the site, appropriate monitoring and notification requirements. It outlines the steps you will be taking before and during application of phostoxin as well as when aerating. Phostoxin can only be used where bin temperatures are 5 C or warmer or it will fail to activate. The colder it is, the longer it will take the pellets to gas off and the longer the bin must be sealed before being aerated."

"As you can see, it is getting more complicated to fumigate stored grain. There are, however, easier solutions to the problem of grain beetles in the grain. You can condition the grain immediately after harvest to bring its temperature down below 20 C so the hot grain doesn't attract the beetles. This is the easiest answer. You can also aerate a bin interior down to minus 20 C for two weeks to kill off the beetles."

"As it gets more complex and onerous to fumigate grain, it is a good idea to look at some other, simpler methods to either avoid the problem or treat it. Phostoxin, Gastoxin and Weevilcide are very dangerous products that need to be handled properly. If you must use them then you'll have to abide by the increased oversight and care required to use it. Improper use can result in death or injury."

March 30, 2015  By Alberta Agriculture and Rural Development