8 June 2001

Fumigation: A valuable backstop

DONT despair if, despite your best efforts, you find live insects in hard-won stored grain because fumigation is a valuable backstop to get you out of trouble, says Ian Clayton-Bailey of pest specialist Igrox.

The company has offered a fumigation service using phosphine gas in the UKs main grain-growing areas for 25 years, treating about 250,000t last season.

"Its very much an option that farmers are not always aware is available to them," says Mr Clayton-Bailey.

Actellic (pirimiphos-methyl) insecticide dust may still be admixed with cereals to counter pests, but as from July this year its approval for use on oilseeds is being withdrawn.

"Thats a real cause for concern for potential mite infestation. However, we have carried out fumigation trials on mites in oilseed rape and can completely control all life stages."

The key benefit of fumigation is that it leaves no detectable residues, he says.

High concentrations of the gas monitored and maintained evenly for up to 14 days by sheeting and sealing should eradicate all insects and eggs from infested grain, he says. "Using our patented gas recirculation system we can get complete control in as little as eight days."

Igrox to the rescue

The Igrox service came to the rescue of Newcastle-upon-Tyne farmer John Spence for the first time this season after he decided to stop applying Actellic (pirimiphos-methyl) dust to his grain. "The dust is not very nice to deal with and I was getting pretty bad headaches so I decided to try to do without it."

At Witchester Farms dropping the insecticide seemed to be working until just after Christmas. "But then we had a rejection for saw-toothed grain beetle and Tyne Grain and Dalgety put me onto Igrox. They treated 700t of barley as well as a bit of wheat later on and have done an excellent job.

"All I had to do was point out where there was any timber and straw in the store through which the gas could escape. They did all the sheeting.

"It cost roughly £2/t which these days sounds expensive. But when you consider that the cost of just one rejection can be £200 its not a lot."

Another grower to benefit from Igroxs services is Michael Bates. He put up a 1000t unventilated on-floor store two years ago on land four miles from his base at Grange Farm, Gainsborough, Lincs, where he grows about 200ha of combineable crops.

"Unfortunately it doesnt have any drying facilities because of the difficulty and expense of getting electrics to it. Its just a concrete platform with a shed over it."

The whole building was sprayed inside with Actellic (pirimiphos-methyl) before the 1999 and 2000 harvests. But while he tried to avoid storing damp grain, problems arose in both seasons.

"I admit we got caught out, but the pressure of farming doesnt allow you to inspect as often as youd like."

First signs of trouble this year were in February when Centurion co-op staff, checking the store monthly, found live insects in a 40t hot spot of about 450t of milling wheat.

"All I had to do was pay the bill which was between £3 and £4/t."

An extra advantage of the Igrox method is that it comes with a three-month guarantee of no further infestation, says Mr Bates.

The phosphine treatment has had no detrimental effect on end use, he adds. "The grain can still go to the same markets as before." &#42

PHOSPHINEFUMIGATION

&#8226 No farmer involvement.

&#8226 No detectable residues.

&#8226 No need to move grain.

&#8226 Acceptable on UKASTA passports.