As we approach corn grain harvest, we thought it was good to remind folks to properly prepare grain storages. Several species of beetles and moth caterpillars can attack stored grain. Once insect infestations are established, they are difficult to control, so a good mindset is “start clean to stay clean.”
Sanitation
Sanitation is the most effective way to prevent stored grain pests. Before adding new grain to a storage, remove all old grain, which may be a source of insect populations that can rapidly infest the new grain. Clean the walls and floor by sweeping, vacuuming, or washing. Inspect and clean dust around doors, seams, vents, and false floors. Repair any cracks in walls with a carbon fiber wall kit or holes in bins.
Do not forget about inspecting the areas around grain bins. Remove any old grain that has collected around the outside of the storage. Mow or remove any grass and weeds around the storage structure. Harvest equipment should also be inspected for lingering, old grain and cleaned before being used.
Chemical Management
After bins have been properly cleaned, storages can be sprayed with a residual insecticide. Bins should be sprayed at least 2-3 weeks before being filled with grain. For long-term storage, grain protectants can also be added to the grain as the bin is being filled. Refer to the Penn State Agronomy Guide for details.
Table 1.3-2 “Products registered for insect control in on-farm stored grain” from the Agronomy Guide
| Treatment site | Insecticide | Amount to use1 | Comments |
|---|---|---|---|
| Residual spray on floor and sides of storage facility | Beta-cyfluthrin (Tempo SC Ultra) | 0.27–0.54 fl oz per 1 gal water | For general surface spot, mist, or crack and crevice application. Use higher rate for longer residual. Avoid contact with treated surfaces until dry. Some reports say that this product may not protect fully against weevils. |
| Residual spray on floor and sides of storage facility | Chlorpyrifos-methyl and deltamethrin (Storcide II2) | 1.8 fl oz per 1 gal water | Clean bins thoroughly before use. Apply only to empty grain bins using automated spray equipment. Use a downward spray from outside the bin. Apply finished spray mixture to equipment, walls, and floor surfaces at 1 gal per 1,000 sq ft prior to storing or handling grain. |
| Residual spray on floor and sides of storage facility | Deltamethrin (Suspend SC) | 0.25–1.25 fl oz per 1 gal water | Clean bins thoroughly before use. Apply finished spray mixture to equipment, walls, and floor surfaces of grain bins at 1 gal per 1,000 sq ft prior to storing or handling grain. Do not allow runoff to occur. |
| Residual spray on floor and sides of storage facility | Malathion | Many trade names are sold; check rates | Many stored grain insect pest species are resistant to malathion. |
| Residual spray on floor and sides of storage facility | Pyrethrins + piperonyl butoxide | Several trade names sold; check rates | Barley, corn, oats, rye, and wheat. |
| Residual spray on floor and sides of storage facility | Spinosad (Contain) | 5.9–10.5 fl oz per 1,000 bushels depending on commodity | Barley, oats, sorghum, triticale, and wheat. Some formulations are approved for organic use. |
| Grain protectants | Chlorpyrifos-methyl and deltamethrin (Storcide II2) | Barley: 9.9 oz per 1,000 bushels | Dilute the labeled rate in 5 gal of water. The final spray volume is 5 gal liquid per 1,000 bushels. See oil manufacturers’ rates for oil solutions. |
| Grain protectants | Chlorpyrifos-methyl and deltamethrin (Storcide II2) | Oats: 6.6 oz per 1,000 bushels | Dilute the labeled rate in 5 gal of water. The final spray volume is 5 gal liquid per 1,000 bushels. See oil manufacturers’ rates for oil solutions. |
| Grain protectants | Chlorpyrifos-methyl and deltamethrin (Storcide II2) | Sorghum: 11.6 oz per 1,000 bushels | Dilute the labeled rate in 5 gal of water. The final spray volume is 5 gal liquid per 1,000 bushels. See oil manufacturers’ rates for oil solutions. |
| Grain protectants | Chlorpyrifos-methyl and deltamethrin (Storcide II2) | Wheat: 12.4 oz per 1,000 bushels | Dilute the labeled rate in 5 gal of water. The final spray volume is 5 gal liquid per 1,000 bushels. See oil manufacturers’ rates for oil solutions. |
| Grain protectants | Pirimiphos-methyl (Actellic 5E) | 9.2–12.3 oz per 5 gal water per 30 tons of grain | Labeled on corn and sorghum. |
| Grain protectants | Methoprene (Diacon II) | 1–14 fl oz per 5 gal water | Insect growth regulator; does not kill adults but prevents the development of larvae into adults, stopping cycling of generations. |
| Surface treatments or topdressing after the bin is filled | Pirimiphos-methyl (Actellic 5E) | 3.0 oz per 2 gal of water per 1,000 sq ft of surface area | Helps prevent establishment of migrating insects if grain cannot be moved. |
| Surface treatments or topdressing after the bin is filled | Diatomaceous earth | Several trade names are sold (Insecto, Protect-It, etc.); check rates | Cover all interior wall surfaces of empty storage area. |
| Surface treatments or topdressing after the bin is filled | Bacillus thuringiensis | Several trade names are sold (Dipel, Biobit, Javelin, etc.); check rates | For Indian meal moth and almond moth control. Does not control weevils or other beetles. |
| Surface treatments or topdressing after the bin is filled | Methoprene (Diacon II) | 0.034 fl oz (1 mL) per 1 gal water per 1,000 sq ft of surface area; see label for further details | Insect growth regulator; does not kill adults but prevents the development of larvae into adults, stopping cycling of generations. |
| Surface treatments or topdressing after the bin is filled | pyrethrins + piperonyl butoxide | Several trade names sold; check rates | Approved for barley, corn, oats, rye, sorghum, and wheat. |
| Bin headspace | Dichlorvos resin strips | Hang one strip per 1,000 cu ft of bin headspace | Barley, corn, rye, oats, sorghum, and wheat. Protects against Indian meal moths. |
| Fumigation | Aluminum phosphide or sulfuryl fluoride (sold under a variety of trade names, including Fumitoxin, Gastion, Gastoxin, Phostek, Phostoxin, ProFume, Vikane Fumigant) | Seek professional assistance | Restricted-use pesticide—extremely toxic and potentially explosive. Strict application procedures are required. |
| Fumigation | Carbon dioxide | Corn, wheat (small grains), sorghum, soybeans | Requires CO2 generator; bin must be completely sealed. Fumigation will take many days to be effective. |
Corn Cribs
Because corn cribs are open, insects are especially difficult to control and fumigation is not an option. Corn cribs should be cleaned properly each year. Never add new grain on top of old grain. Residual sprays and grain protectants may provide some control if corn is being stored long-term.
Warning
Pesticides are poisonous. Read and follow directions and safety precautions on labels. Handle carefully and store in original labeled containers out of the reach of children, pets, and livestock. Dispose of empty containers right away, in a safe manner and place. Do not contaminate forage, streams, or ponds.
