Farm-stored soybean insect mamagement

Robert  G. Bellinger 

The quality of farm-stored soybeans is at its peak when it is loaded into the bin for storage. After this point the best you can do is to try to maintain this level of quality. Therefore, it is important to maximize the quality of the beans prior to storage. At harvest make sure that your beans are dry enough for storage, and that your harvesting equipment is adjusted to minimize breaking or cracking the beans.

Only load soybeans into a thoroughly cleaned, empty bin. Don't load beans on top of older beans! When you load soybeans into the storage bin make sure your loading auger and mechanical spreaders in the bin are in good condition and will not damage the beans. Run the auger at full capacity (run at a slow speed) to minimize breaking beans. The cleaner and drier the beans are going into the bin the better.

Do not overfill the bin. Level the beans in the bin as soon as it is filled and immediately begin aeration to cool the beans. Poorly controlled temperatures are the most important cause of stored soybeans going out of condition. Get the beans cooled down to the outside air temperature as soon as possible. Keep the bin temperature no more than 10 - 15^oF of the outside temperature during storage. Ideally the temperature should be maintained at 35 - 40^oF as soon as is possible.

Proper harvest, loading and storage of soybeans is critical for managing potential insect infestations. Proper storage management provides the best control for the cost. In any insect management system it is important to not rely on insecticides. This is particularly true for stored grains, as there are few insecticides registered in this area, and fewer still for soybeans. Also, insecticide resistance has already made at least malathion essentially useless in many stored grains environments.

Insects will stop feeding and reproduction at temperatures below about 50^oF. Because soybeans held at moisture levels that will not allow mold growth, properly cooled and dried soybeans tend only to be infested by Indian meal moth. This moth infests the grain starting from the top of the bin.

The Indian mean moth (adults only) can be controlled using DDVP (dichlorvos) resin strips in the head space of the bin. Using 1 strip per 1,000 cubic feet. Change strips monthly. You may alternatively, or also, use a Bacillus thuringiensis (Bt) product (for example, Dipel) as a top dressing (grain surface treatment), applied immediately after bin loading (controls larvae only.) Diatomaceous earth products may also be use here but monthly treatments will be needed.

Because properly loaded and stored soybeans tend to suffer fewer insect infestations than other grains, while bins must be thoroughly cleaned, it may not be necessary to treat bins (bin surface treatment) before loading soybeans, to treat or beans (grain protectant) when loading. In fact, few are registered for these uses. While soybeans are less prone to insect infestations, you must stil regularly check the beans - check storage temperature and moisture levels and for flying moths and surface crusting in the top of the bin.

These recommendations are based on active ingredients. These recommendations are not a substitute for carefully reading the pesticide label. Other registered products not mentioned here may be as effective.

Note: Product use sites - Read the label carefully! Use sites vary widely from product to product. Some products may only be used to treat grain storage bin surfaces and not grain; few products may be used for both applications. Grains that may be treated vary with product.

Note: Product rates - Read product labels carefully! Rates vary with formulation of product used, use site/crop being stored, anticipated storage time, and pest species, and pest development stage. Some products may only have one (1) application made to a load. Period of control can vary with pest insect species and is shortest at the lowest rates.

Note: Pests controlled - Read the label. Not all products control all pests, especially at the lowest rates. Bacillus thuringiensis (Bt) products control only caterpillars (moth larvae), and not beetle grubs. Control will be slow.

Note: Formulations - Read the label. Choose the correct formulation. Be sure you have the necessary application and safety equipment and PPE to make an application with the product formulation you consider. Some formulations may not be applied directly to grain. Some products may be applied with water or food-grade oil or soybean oil, usually except for peanuts.

Note: Insecto (a diatomaceous earth product) - "Insecto Control Plan" calls for dusting the empty bin, treating the bottom 2 feet of grain, treating the top 2 feet of grain, top-dressing leveled grain with this product at labeled rates. Inspect grain bi-weekly. Organic Materials Review Institute (OMRI) Listed.

Note: Fumigants are the most effective way of controlling insect infestations in stored grain; however, fumigants provide no residual control. Fumigants are Restricted Use Pesticides (RUPs) and may be purchased and used only by licensed applicators. These pesticides are Danger, Danger/Poison labeled because of acute toxicity. Fumigants have strict application requirements via the label and applicator manual. Product-specific training and/or product company supervision may be required, especially for liquid and gas formulations.

Note: Malathion is not recommended because of pest resistance and tolerance issues in international markets.

Grain Bin Surface Areas and Capacities.

Page maintained by: Pawel Wiatrak, pwiatra@clemson.edu