15 degrees Celsius or cooler. That’s where temperatures should be at in stored grain to prevent an insect infestation.
“The key is if you can get your grain temperature down to plus-15 as quickly as possible, any bugs that are in there will not be feeding and will not be reproducing,” explains Blaine Timlick, stored products entomologist at the Canadian Grain Commission.
He recommends having a checklist or protocol to follow for preventing and managing insect problems with grain in storage, starting with an evaluation of the storage structure. Are there openings, leaks or vents that could cause trouble? How clean is it? Poor sanitation or residues can reintroduce a previous infestation, notes Timlick.
So what do you do if you find bugs in a bin? First, they need to be identified to determine the right response (the CGC has some helpful tools).
“Treating grain with contact insecticides is really a prophylactic measure,” he says. “In other words, they work best if you put them on the grain before you think you have a problem, rather than after.”
Fumigation is a limited option for most on-farm cases, he says: “Grain bins on farm were never designed to hold gas, and it makes it difficult to have an effective fumigation.”
A heated grain dryer could have a role in killing insects, as most stored grain pests will die when temperatures hit 60 degrees, but there are downsides.
“You’ve possibly dried grain more than you want and then you have to get the grain temperature back down to an appropriate level,” notes Timlick.
In most cases, mother nature’s cool temperatures, combined with aeration when temperatures drop, will prevent an insect population explosion (hear more about that in the Wheat School above).