Grain storage insect control is a little like pulling your favorite wool sweater out of the spare room closet, only to discover a scene out of the teen horror film, The Moth Diaries.
Turns out your favorite clothes are moths’ favorites too. Cashmere, argyle, wool, leather, even your purple and gold Vikings knit hat isn’t safe. Nothing escapes the havoc wreaked by the insatiable tineola bisselliella, aka the common clothes moth.
It’s irritating. Especially when you’d carefully cleaned and stored your clothes for the season. At least your losses probably are probably more sentimental than monetary. Not losses in the thousands of dollars anyway. (Although you could argue that your NFL gear is priceless.)
Imagine that instead of losing a few sweaters, socks, and hats to the moth larvae brigade, you discover an insect infestation in your grain silo or bin.
Now we’re talking serious financial loss on a whole new level, potentially thousands of dollars.
Is there a way to manage your stored grain that actually deters insects? Glad you asked, because yes, there is.
Readying Your Bin/Silo with Grain Storage Insect Control in Mind
As part of your farm’s overall biosecurity, you can take steps to create a hygienic environment for stored grain. It’s key to preventing pests from sneaking into your stored grain. One obvious benefit to controlling pests is getting the best price, because your grain stays in optimum condition. Another is controlling grain quality long enough to use the market to your advantage.
Cross-contamination is the initial cause of many instances of insect infestation. Insects, including weevils, moths, beetles, grain borers and mealworms, can find their ways into grain storage bins when they’re inefficiently cleaned and prepared.
To avoid this, thoroughly clean empty bins, subfloors, aeration ducts, elevators, augers, and all grain harvesting machinery. Weatherproof grain storage bins, repair and seal cracks or holes, and treat with residual insecticides. If the perforated floor or aeration duct screens can’t be removed, cleaned, and treated – fumigate.
Treat the outside surface of your bins, underneath bins, and the ground surface around bins to six feet. Don’t forget to treat harvesting and grain handling equipment too.
Besides preparing your storage facilities and grain handling equipment for harvest, it’s equally important to prepare grain for storage at harvest.
Preparing Your Harvested Grain for Storage
Although pest control starts in the fields during the growing season, it doesn’t end at harvest.
Adhering to acceptable grain moisture content levels at storage is essential to deterring insects. However, overdrying grains can damage them and invite ‘secondary’ insects into the picture. Researchers at Iowa State University found that moisture levels below 10% made soybeans more brittle and likely to split. So it’s essential to find that delicate balance in grain moisture content.
Moisture needs to be low enough to prevent spoilage and insect infestation for sure, but the solution isn’t solely initial grain moisture content.
The University of Minnesota Extension recommends grain protectants prior to storage. Chlorpyrifos-methyl, malathion, and pirimiphos-methyl are approved grain protectants that may be applied in dust or liquid forms. The effectiveness depends on proper mixing and application, as well as grain temperature and moisture.
Grain protectant failure is most commonly due to temperature and moisture. Experts recommend not treating grains with a higher moisture content than 13%, or higher temperature than 90 degrees.
Once grain has been stored, how do you keep it insect free? Create an environment that is unfavorable for insects.
Creating an Unpleasant Environment for Insects
How you store your grain is important. Overfilling grain bins is a common mistake. Not leveling the grain at the top is another one. Grain should be level with at least six inches of space at the top. You can dust the top of the leveled grain with a surface treatment. But be aware that surface treatments won’t control established infestations, and they can’t be disturbed.
Renowned entomologist, Harold Shepard, wrote back in 1947 that experiments showed grain insect activity was slight at 45° Fahrenheit. And at 43° there was virtually no insect activity. So keeping grain between 40 and 43 degrees has a big impact on grain storage insect control.
Experts today agree that grain temperature is one of the biggest factors in maintaining stored grain quality. Managing your grain’s temperature and moisture levels determines how long you can safely store grain. Low temperatures and moisture mean stored grain can remain safe from insect infestations for months.
On the other hand, high temperatures and moist grain can become problematic in days.
Farmers catching up on work that was neglected during harvest season shouldn’t ignore stored grain. Your grain storage temperatures must be regularly monitored to ensure continued grain quality.
Monitoring Your Grain’s Temperature to Deter Insect Infestations
According to Grain Storage Pest Control Guide, effective grain hygiene and aeration cooling can overcome 85% of pest problems. There’s no reason why insects should get the chance to spoil your grain.
Heat is an indicator of problems in stored grain. These days temperature monitoring cables are key in detecting ‘hot spots’ in grain storage. This kind of monitoring alerts you to the presence of insect activity through real-time data delivered straight to a smartphone or tablet. You can put an end to insects in stored grain before they become a bigger problem.
The information you collect can be used to troubleshoot problems and make savvy decisions about your stored grain anytime, from your workshop, barn, or anywhere there is Internet.
Grain monitoring systems help document grain storage information for future reference. This provides invaluable data to make an array of grain management decisions.
Fumigation as a Last Measure for Grain Storage Insect Control
In the United States, grain is written off as infested when there are two or more live weevils, or other insects, found within a stored grain sample. Getting on top of potential infestations — before they can detract from quality or commercial value is vital.
Grain hygiene, bin hygiene, bin aeration, and temperature monitoring are the best preventive measures against grain pest infestation. If, despite your best efforts, your grain suffers an insect infestation, properly fumigating grain is the last alternative.
High quality grain that gets the best price at market is free of insects, dockage, and chemicals.