In just a few weeks, a major portion of our 2013-14 winter wheat crop will go into some type of storage. In fact, if this message is prompting you to prepare your bins, you are probably behind the curve. Nevertheless, there is perhaps no pest control strategy more important in successful storage of wheat than bin preparation. Certainly there is no less dangerous and expensive alternative. The following is a suggested check list to insure you have done all you can do to prevent an insect problem in your bins.
Before the Wheat is Binned
- Bin preparation should occur at least 2 weeks ahead of binning.
- All old / leftover grain and associated dust and trash should be removed from the bin.
- Insure that your storage provides sound protection from the outside. Patch, caulk, or otherwise cover places in the bin walls, joints, and roof that will allow the entrance of water and insects. A ¼-inch hole might seem small to you, but it is a mega-tunnel to insects crawling up the outside bin wall.
- Clear spilled grain, weeds, and other organic matter from around the exterior of bins, including pits, conveyers, and legs.
- Fumigate under the perforated floor and / or ducts.
- Treat the inside of the bin with an approved dust or liquid insecticide. Labels for these products have recently changed so be sure you are making a proper application.
- Treat around the exterior of the bins with an approved insecticide.
- Inspect and clean every piece of equipment that is used to haul / transfer grain. For example, combine, grain wagons, truck beds, pits, augers & belts, and legs.
- Beyond grain moisture and temperature, thorough sanitation is the single most important preventative control practice. Neglecting to do this can result in your “seeding” the grain stream with insect pests.
- Some storage managers will treat the grain with a grain protectant. Although this is more common in wheat than in corn (there are no protectants for soybean), with good management, and if you are only holding until the next crop, this is probably not needed.
- These products are quite expensive.
– If using a grain drier, remember to apply the protectant AFTER the grain has cooled. Applying to hot grain will cause the product to deteriorate.
– This cost can be reduced by applying the treatment to only the first and last load.
- Fumigation under perforated floors and in duct systems can be extremely helpful but is quite dangerous and should be completed by trained professionals.
- Considerable specialized training, equipment, and supplies are required to perform a safe and effective fumigation, not to mention extensive record keeping.
– If your fumigation is not done properly, it will not reach the areas of need and you will have accomplished nothing, all at a relatively large expense.
After the Wheat is Binned
Move air through the wheat any time you can. Reducing the grain temperature has a direct effect on the growth of insect populations. This is why we have more trouble in wheat than in corn. Even in a hot Kentucky summer, there are times when the outside air is cooler than the grain mass. I strongly recommend the use of automatic fan controllers. Information on these devices can be found on the University of Kentucky BioSystems and Agricultural Engineering Web site at (http://www.bae.uky.edu/ext/Grain_Storage/default.htm) or from Dr. Sam McNeill of that department.
In Kentucky, we sometimes have problems with moth pests in addition to beetles. The caterpillar (young stage) of these pests is the important stage, and is restricted to the grain surface.
- A “cap out” treatment: applying a layer of one of several products to the top 4 inches of the grain will provide a barrier. Products containing Bacillus thuringensis (Bt) are commonly used for this.
- Deployment of “Insect Shield Strips” in the void above the grain mass may provide control of various grain moths before they can lay their eggs.
Regular checking of your stored grain for insect and storage problems can be of great value. For grain spoilage and for surface infesting caterpillars (for example, Indian meal moth) simply looking in the hatch and using your nose to smell the grain can be of major value. Additionally, pheromone-baited traps can be used to capture the moth (adult) stage of the caterpillar pests to provide advanced warning. Pitfall traps are a relatively simple way to detect the presence of stored grain beetles within the grain mass. This takes a little practice, but will be increasingly more useful as one gains experience with them. Though we do not have definitive thresholds for these measures, the traps will tell you when the insects are present and, by taking samples through time, how the population is changing. After one has used these techniques for several years, they may also provide a measure of increasing or decreasing risk of insect damage.
For fumigants and insecticides that may be used in stored wheat, please see Insecticides Recommendations for Small Grains-2009 (ENT-47) available at: http://pest.ca.uky.edu/EXT/Recs/ENT47-SmallGrain.pdf or from your County Cooperative Extension Office.
“If you can only do one thing, store clean dry grain in clean dry bins!”
By Doug Johnson, Extension Entomologist