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How to Prevent Stored Grain Pests

September 5, 2018

With harvest just around the corner and a lot of farmers interested in storing grain this year there will be an increased need to make sure that insects don’t become a problem for that grain. There are many preventative measures that can be taken that greatly reduce the risk of stored grain insect issues. The first step to make sure a storage facility or grain bin doesn’t become infested is to have a sanitation program in place and the second step is routine scouting.

Stored grain is susceptible to insect feeding that can cause both direct and indirect damage. The direct damage occurs when insects feed directly on the kernel or seed, which reduces the germination, weight and nutritional value of the seeds. Insects cause indirect damage to stored grain by causing increases in the temperature of the grain, promoting mold growth or by simply being present in the grain as a contaminant when it is marketed. All of these conditions result in a downgrading of the grain which reduces the market value.

The best way to preserve the value of a crop is to prevent an insect infestation from occurring. This can be achieved during the late summer or fall by cleaning the bin thoroughly before a new crop is stored. If possible, new grain should never be stored on top of old grain as this will increase the risk of infestation. Once grain is stored, it should be scouted routinely to ensure that an infestation doesn’t occur. Below are recommendations to reduce the risk of infestation by stored grain insect pests.

The first step to prevent stored grain pests is to have a sanitation plan in place for each storage facility. It is estimated that sanitation accounts for approximately 80% of an effective stored grain insect pest prevention program. This is in part due to the fact that the purpose of sanitation is to remove any pests (insects or rodents) that may currently be present in a bin and also remove any potential sources of food or attractants for potential pests. While cleaning the bin, it should also be inspected to ensure that it is weatherproof and also that there aren’t any areas where pests could easily enter. The steps for sanitation of a bin are below.

  1. Inspect the roof for any leaks and repair if present.
  2. Inspect the bin for any cracks, holes or gaps and seal if present.
  3. Remove any old grain from the bin. New grain should never be stored on top of old grain.
  4. Clean the walls and floor of the bin to remove any grain, dust or debris by sweeping or vacuuming.
  5. Clean any old grain spills from around the bin. These spills can attract pests to the bin.
  6. Clear a perimeter of 10 feet around the bin of any vegetation or debris.
  7. Clean all grain handling equipment prior to harvest. This includes augers, wagons, grain carts, trucks, combines, grain cleaners and aeration fans.
  8. Seal the bin door once the bin has been filled with grain.

Pre-binning Insecticide Treatment
After bin sanitation has occurred a pre-binning insecticide can be applied to the walls and floors of the bin 2-3 weeks prior to harvest. These insecticides provide a residual and can further reduce the risk of infestation. Pre-binning insecticide applications are most effective when air temperatures are above 60 °F due to increased insect activity. The outside walls and base of the bin may also be treated with an insecticide that clearly states it is for perimeter treatments. Insecticides labeled for pre-binning applications to empty bins:

  • Tempo SC Ultra (beta-cyfluthrin); re-enter when spray has dried; do not allow run-off to occur.
  • Suspend SC (deltamethrin); re-enter when spray has dried; do not allow run-off to occur.
  • Centynal (deltamethrin); re-enter when spray has dried; do not reapply within 21 days.
  • Malathion 5EC (malathion); re-enter after 12 hours; use this product according to the label.
  • Pyronyl (pyrethrin); re-enter after 12 hours; do not reapply within 30 days.
  • Dryacide and Insecto (silicon dioxide); re-enter once dust settles; over application may reduce the grade of grain.

*Always read and follow the label instructions and wear personal protective equipment to prevent injury. This list is not meant to be comprehensive.

Source: Adam J. Varenhorst, iGrow