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UK-IPM Checklist for Controlling Insects in Stored Corn

Before long the combines will be back in the field, this time with corn headers on. Now is the time to begin thinking about how and where to store all the corn that is not going directly to market. Below is a check list that we have developed to help you keep up with what is going on. By adding some dates, location identifications, and a few check marks, it may also be used to serve as a record for your corn storage program.

More and more often we get calls from buyers wanting to know where the commodity was grown and how it was handled. This is an easy way to help answer those questions. Also, you will find listed the currently labeled insecticides for use on stored corn. Remember, these products are changing rapidly. Be sure to check the label of any insecticide you use. You may also want to check with your buyer, they may have further restrictions.

Whatever you do, with out question the two most important fundamentals of grain storage are: plan ahead and put clean, dry, grain in clean, dry bins!

UK-IPM Checklist for Controlling Insects in Stored Corn

Doug Johnson, Extension Entomologist and Sam McNeill, Extension Agricultural Engineer
University of Kentucky

Before Harvest / Pre-Binning

  • Clean all equipment used to handle grain (Examples: combines, carts, trucks, receiving pits/hoppers) thoroughly to remove old grain, trash, and debris that might contaminate the new crop.
  • Use pressurized air/water.

  • Remove all old grain from inside storage bins. Use a shovel, broom and vacuum. Every kernel counts!

  • Check for holes and cracks in bin roofs and walls. Seal them to prevent leaks and entry of insects and rodents. (Look closely around ladders, roof vents and other openings).

  • Treat the interior floor and bin walls with an approved insecticide.

  • Remove spilled grain around pits/hoppers, and storage bins.

  • Mow, spray or remove weeds/grass/vegetation around storage bins.

  • Treat the outside base of bins and the surrounding area with an approved insecticide.

  • Fumigate the space beneath the perforated bin flooring. Warning!!! Fumigation is complicated and dangerous. If possible, hire a commercial fumigator. Restricted use pesticide certification is required for purchasing the fumigants. Specialized training from a commercial applicator is strongly recommended. Specialized equipment, including gas masks, self-contained breathing apparatus, and fumigant gas detection equipment is required for safe, effective and economical applications. Obtain and read the product label and manufacturer's instructions.

During Harvest / Binning

  • Operate combine(s) to minimize grain damage, trash and fines or clean grain mechanically.

  • Store corn at 15, 14 or 13% moisture when holding for 6, 9, or more than 9 months, respectively.

  • Consider applying a grain AProtectant@ to the bulk grain mass after drying and cooling. Do NOT apply before heated air drying or to hot grain!!

  • Consider applying a ACap out@ treatment to the grain surface (Do not apply if a Protectant is used).

Post-Harvest / After Binning

  • Use Apitfall" traps to monitor insect activity. Use three traps per bin. Check traps weekly in August and September. In colder months trap for four days each month.

  • If insects are detected have them identified and classified as primary or secondary feeders. Be especially interested in the true Aweevils@.

  • If insects are numerous enough to result in a discount or you are planning to hold the grain into the next warm season consider having the grain fumigated.

  • Monitor grain temperature and moisture monthly.

  • In September, run fans to cool corn to near 60oF.

  • In October, run fans to cool corn to near 50oF.

  • In November, run fans to cool corn to near 40oF.

  • After cooling to 40oF, seal fans with plastic to prevent air movement in the bin.

  • Operate fans any time the need arises to control temperature or moisture.

Insecticides and Fumigants Recommended for Corn

We recommend that you do not use malathion for any treatments. Most forms of malathion are no longer labeled for use. More importantly, the product no longer provides adequate insect control. See: ENT-16 Insecticide Recommendations for Corn.

Empty bins - applied to walls and floor: Tempo7 SC Ultra. DO NOT APPLY TO GRAIN!

Under Floor Fumigants - Chloro-pic7 (Can not currently be shipped-you will only find it if your local dealer has some on hand or in large e.g 200 lb. bottles), Methyl-Bromide, Phostoxin7 / Fumtoxin7. THESE PRODUCTS ARE EXTREMELY DANGEROUS.

Protectant - applied directly to the bulk grain: Storcide7 or Actellic® 5E.

Cap out treatment applied to the top 4" of grain - (Do not make this application if a protectant has been applied to the bulk grain) Actellic7 5E for beetles or products containing Bacillus thuringiensis, e.g. Dipel7, Javelin7, Sok-B.t.7 etc. for Indian meal moth.

Bulk Grain Fumigants - Phostoxin7 / Fumtoxin7.

For more information about crop and livestock pests, visit "Insect Management Recommendations".

Last revised: 28 July 2003

Cooperative Extension Service, University of Kentucky College of Agriculture

Educational programs of the Kentucky Cooperative Extension Service serve all people
regardless of race, color, age, sex, religion, disability, or national origin.


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