Wheat harvest is well underway and some growers will be storing their harvest on farm in bins for an extended period of time. Stored grain pests can cause significant losses to stored grain if left unchecked. This is particularly true for wheat because it is often in storage throughout the hot summer months when insects are most active. There is an entire complex of insects that can infest wheat stored in bins. There are several weevils and other beetles as well as some caterpillars that will feed on grain during storage. Many of these species live for several months and some may live for up to 2 years. The first line of defense against these invaders is placing grain into a clean bin.
An important source of infestations in grain storage facilities is old grain that has been left in or around the bin. Even a small amount of grain can produce a large number of stored grain pests. Stored grain insects are very small and long lived. They can often survive for long periods of time with little moisture or food. Before placing fresh grain into a bin, floors should be swept clean of ALL old grain. Any spilled grain near the outside of the bin should also be removed. One area growers often forget to clean is the augers. Once all bins and equipment have been cleaned, bin floors and walls should be treated with a residual insecticide just prior to placing fresh grain in the bin. Storcide II, Malathion or Tempo Ultra can be used to treat the inside of empty bins. Malathion is NOT LABELED for rice storage facilities. Also, liquid formulations of Malathion cannot be applied directly to grain. Remember, proper sanitation of bins will go a long way in preventing insects from attacking wheat while in storage.
Once wheat is ready to go into the bin, it should be treated with an insecticide if it is going to be in storage for very long. The Stored Grain Insect Control section of MP 144 gives a list of recommended insecticides and rates for stored wheat. Application rates for bin wall and floor treatments can also be found in this section of MP144.