Pest and Diseases Image Library, Bugwood.org
Several insects that feed on fungi are commonly found in grains stored on Pennsylvania farms. One of the more common species is the hairy fungus beetle, Typhaea stercorea (L.). This insect does not feed on the grain itself, but on fungi which grow on high moisture grain. Its presence is an indication of moldy grain. It is seldom the primary insect species in an infested grain bin.
The adult is a small, brownish beetle about 1/10 of an inch long and covered with hairs. It resembles the drugstore beetle, but is smaller and has club-like antennae instead of saw-like, antennae. Other stages of the insect are seldom seen in grain bins.
In its natural environment, the adult hairy fungus beetles feed on molds growing on stored grains, where females deposit their eggs. The insects are frequently found in cornfields, where they are attracted to decaying kernels of exposed ears. Adults may also be introduced into grain bins on newly harvested grain. Very little information is available on the life cycle of this pest.
The hairy fungus beetle does not damage stored grain. Its presence in a bin indicates mold growth on the grain or introduction of moldy field corn during harvest. Well managed grain is typically not infested with the hairy fungus beetle. However, populations of the hairy fungus beetle are kept under control if proper sanitation techniques are used and the grain moisture level is maintained at 13 to 15 percent. When grain is placed in storage and not monitored periodically, moisture can accumulate in the bin and molds then develop. This is true even in grain that was originally dried below 15 percent moisture. The presence of molds and insects in the grain can cause rejection of a sale or reduced market value.
Current government programs and low crop values encourage more on-farm, long-term storage of grain. Grain in storage over extended periods of time requires good management practices to prevent moldy grain. The presence of fungus-feeding insects in grain indicates the need to control grain temperature and moisture and perhaps to fumigate infested bins.
Control of this insect begins with good management. Before new grain is placed in a bin, the old grain should be thoroughly removed from the walls, floors, and augers inside the bin. Harvest equipment should also be cleaned before reuse. If possible, the grain should be screened to remove broken kernels and other contaminants.
After being placed in a clean bin, the grain should be checked, at two week intervals during warm months and one month intervals during cooler months, for the presence of hotspots, moldy areas, and insects. If any of these conditions exist, the grain should be aerated to lower the moisture level and temperature.
Fumigants should be used only as a last resort. Because of the high toxicity of registered fumigants and the technical knowledge needed for their proper use, a qualified pesticide applicator should be contacted if fumigation is required.
Pesticides are poisonous. Read and follow directions and safety precautions on labels. Handle carefully and store in original labeled containers out of the reach of children, pets, and livestock. Dispose of empty containers right away, in a safe manner and place. Do not contaminate forage, streams, or ponds.
Authored by: Dennis Calvin, Assistant Professor
Last updated October 1988