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 loading the best you can do is to try to maintain this level of quality. Thus, it is important to maximize the quality of the beans prior to storage. At harvest make sure 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 loading 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 when loading. Run the auger at full capacity (run at a slow speed) to minimize breaking beans. And 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 – 15oF of the outside temperature during storage. Ideally the temperature should be maintained at 35 - 40oF.
Proper harvest, loading and storage of soybeans is critical for managing potential insect infestations. Proper storage management provides the best control for the cost. It is important in any insect management system 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 50oF. Because soybeans held at the 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 from the top of the bin. This moth can be controlled using DDVP resin strips in the head space of the bin, using 1 strip per 1,000 cubic feet (controls adults only). Change strips monthly. You may alternatively, or also, use a Bacillus thuringiensis (Bt) product (for example, Dipel) as a top dressing (gain 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, it is not usually 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, do not fail to regularly check the beans – check storage temperature and moisture levels and flying moths, and for surface crusting.
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.
Pest or Application Type |
Active Ingredient(s) |
Rates |
Site(s) |
Re-entry Interval |
Comments |
Bin Repair & Sanitation |
|
|
Interior and exterior of grain storage bins prior to loading. |
|
Sanitation is critical. Repair (fix and fill holes, cracks) and thoroughly clean bins before loading with grain. Most pesticide product labels note sanitation as a pre-treatment procedure! |
Empty Bin Residual Sprays (Bin interior surface treatment) |
Diatomaceous earth (DE) |
1 lb./1,000 sq.ft. of surface |
Empty bins |
|
Applied through aeration fan. May meet organic requirements. |
Grain Top-Dressing (Stored grain surface treatment, especially for Indian-meal moth larvae- Applications are to leveled grain) |
Bacillus thuringiensis
Diatomaceous earth (DE) (Insecto) |
1 lb./10-20 gal. water/1,000 sq.ft.; see label
4 lbs./1,000 sq.ft. |
|
|
Apply to surface and rake into top 4 inches of grain; see label instructions. Controls only larvae. May meet organic requirements. Especially for Indian-meal moth. May require second application for heavy infestation. Apply at monthly intervals. May meet organic requirements. |
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 registered for empty bin treatments (labeled EC formulations only) and for grain protectant treatments (labeled dust formulations only) for some grains. However, malathion is not being recommended here as it is not seen as effective by many because of wide-spread insect resistance to it, especially in the Indian-meal moth. Malathion also degrades rapidly at high temperatures. Further, international tolerances for malathion on grain have been lowered and are now much lower than U.S. tolerances, effectively making malathion treated grain unmarketable outside of the U.S. Grain buyers are telling growers that they will not accept grain treated with malathion.
Grain Bin Surface Areas and Capacities - R.G. Bellinger 01/08
Bin Diameter |
Grain Surface Area |
Approximate Surface Area |
Bushels per |
Approximate Bin Head-space |
15 |
177 |
(Height x 47) + 354 |
141 |
59 x cone height |
18 |
254 |
(Height x 57) + 508 |
204 |
85 x cone height |
21 |
346 |
(Height x 66 ) + 692 |
277 |
115 x cone height |
24 |
452 |
(Height x 75) + 900 |
362 |
151 x cone height |
27 |
573 |
(Height x 85) + 1146 |
458 |
191 x cone height |
30 |
707 |
(Height x 92) + 1400 |
566 |
236 x cone height |
33 |
855 |
(Height x 104 ) + 1710 |
685 |
285 x cone height |
36 |
1,018 |
(Height x 113) + 2000 |
815 |
339 x cone height |
42 |
1,385 |
(Height x 132) + 2770 |
1109 |
462 x cone height |
48 |
1,810 |
(Height x 151) + 3,620 |
1448 |
603 x cone height |
54 |
2,290 |
(Height x 170) + 4580 |
1833 |
763 x cone height |
60 |
2,827 |
(Height x 188) + 5654 |
2263 |
942 x cone height |
