Know the rules before using phosphine fumigants

Products such as Phostoxin, Gastoxin or Weevilcide are highly toxic and there are easier ways to deal with grain beetles

Using fumigants for grain beetle control in stored grain has become more complex, says a provincial crop specialist.

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

Phostoxin is used extensively to control grain beetles in stored grain, both on farm and at the grain elevator. The Pest Management Regulatory Agency (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,” said Brook. “These certificates can be obtained by studying and taking the Farmer Pesticide Certificate exams.”

Certificates without an expiry date are no longer valid as they were issued prior to 2008, he said.

“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.”

When using these fumigants to deal with grain beetles or Richardson ground squirrel problems, applicators must have the right equipment, said Brook. This includes an approved air-purifying, full-face gas mask with a chin strap, and a front- or back-mounted canister approved for phosphine whenever handling this pesticide.

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

“As well, treated bins should be aerated prior to re-entry,” said Brook. “Treated areas must have posted placards. Warning placards must be placed on every possible entrance to the fumigation site.”

It is also illegal to move treated products over public roads or highways until they have been aerated and the warning placards removed.

In addition, a fumigation management plan must be in place.

“The plan must address characterization of the site, appropriate monitoring and notification requirements,” said Brook. “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.”

But there are less complicated ways to deal with grain beetles, he added.

“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 -20 C for two weeks to kill off the beetles.”

Producers should consider whether fumigation is the best course of action, he added.

“Phostoxin, Gastoxin and Weevilcide are very dangerous products that need to be handled properly,” said Brook. “If you must use them then you’ll have to abide by the increased oversight and care required to use them. Improper use can result in death or injury.”

For more information, call Julie Sisson with the PMRA at 403-393-1576 or the Alberta Ag-Info Centre at 310-FARM (3276).

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