Weather has been good for getting corn out of the field and some of you may be planning to store your grain.  Last week, I put together part one “Be Ready to Store Your Corn-Part 1”. This is the second part of a chapter on storing and protecting corn by Dr. Michael Toews, former UGA entomologist, Tifton on the proper management of stored grains .  I encourage you to read part 1 if you haven’t before reading this blog entry. It is a great primer to storing any corn.  We have a very good crop and with prices down, we don’t need to lose any quality if possible. Now for part 2.

Part 2:  Once your bins are cleaned and treated (see part 1) and the areas around all your bins are clean and treated then you should be ready to begin proper storage of your new crop. It is most important to store only clean and dry grain.

• Store the grain at the appropriate moisture content. Insects and molds require moisture to survive. A general guide to proper moisture content is shown in Table 2.

Table 2.  Recommended maximum moisture content for grain in aerated storage bins

• Store clean grain. Removing or equally dispersing fine particles and other foreign material will increase aeration efficiency and the effectiveness of grain protectants and fumigants. The following steps contribute to clean grain: effective in-season weed control, properly adjusted combines, use of a grain pre-cleaner, coring the bin after it has been loaded, and use of a mechanical spreader at the top of the
• Once the grain is in the bin, make sure the surface is level and the bin is not over filled. Leave a few feet of the straight side of the bin as air space to facilitate aeration and monitoring. If your bin does not have a spreader, unloading one or more loads of grain will help level the central peak as well as uniformly distribute fine particles that otherwise accumulate in the center of the bin.

Application of Grain Protectants

• Growers who will be storing for more than 6 months should strongly consider application of a grain protectant (Table 3). Apply an approved grain protectant directly to the moving grain stream at the bottom of the bucket elevator or auger so the material has an opportunity to contact as many kernels as possible as the grain is moved.
• UGA Extension recommends that grain be conditioned with a cooling cycle or similar procedure before applying the However, recent data suggests that deltamethrin (Centynal EC or Defense SC) and spinosad (Sensat) are heat stable up to 200° F, while s-methoprene (Diacon IGR) and pirimiphos-methyl (Actellic 5E) were degraded by high heat.
• Position the insecticide nozzle as close to the auger flighting as possible to minimize insecticide drift.

Table 3.  Insecticides labelled for direct application to grain as a grain protectant

Insect Management

• Stored grain insects thrive in warm grain. The hotter it is, the faster insects feed, grow and reproduce. Conversely, stored grain insects quit developing when temperatures are below 60°F. Grain temperatures are optimally managed using thermostatically controlled aeration that enables the fans to operate only when the outside air temperature is cooler than the set point. Once the grain reaches the set point temperature, set the thermostat to the next cooler set point. Growers in the deep south should use temperature set points of 75°F, 65°F and 45°F, whereas growers north of a line between Columbus and Savannah should use 70°F, 60°F and 40°F. It is important not to let the grain freeze as this will result in “sweating” when the grain warms in the spring. Temperature cables, moisture sensor cables, and automated aeration controllers make aeration more efficient.
• Initiate a systematic and thorough insect-monitoring system. Check the grain every 21 days from spring to fall and monthly in winter for the presence of insects. Five trier samples or probe traps should be sufficient on each sampling
• If you begin to find insects such as weevils or lesser grain borers, sell the grain, move the grain to another bin and apply a grain protectant as you move it, or fumigate the grain (Table 4). Read the fumigant label and applicator guide carefully. Follow the instructions provided because the label is the Aluminum phosphide is the most frequently used on-farm fumigant. It requires the preparation of a fumigation management plan before any fumigant is applied. If there are leaks in the bin, the fumigant cannot be held long enough to kill the insects. Seal all openings before loading the bin, including the aeration fan, top vents, eaves, roof entry door and side entry door. Many fumigation attempts fail because the gas is not held long enough. Read the fumigant label to determine how long it will take the fumigant to reach a lethal level. It may take a day or two to reach the desired concentration; therefore, leave the bin sealed for the recommended length of time. A closed-loop fumigation can make fumigation more efficient and safe. In this method, fumigant is circulated in a pipe outside the bin from the top to the bottom and then drawn up through the grain to the surface:

Table 4. Grain Fumigants