Get Rid of Grain Weevils - Western Fumigation

Facts About Grain Weevils

All the information about grain weevils you need.

The adult grain weevil, Sitophilus granaries (Coleoptera: Curculionidae) is a somewhat cylindrical beetle about two-tenths of an inch long. The head is prolonged with a distinct snout extending downward from the head for a distance of about one-fourth the length of the body (this is the typical weevil snout, which is actually an extension of its mouthparts and not a snout at all). The weevil is polished red brown to black with ridged wing covers and a well-marked thorax with oval pits. Unlike rice and maize weevils, the grain weevil cannot fly. The egg hatches in a few days into a soft, white, legless, fleshy grub which burrows inside and feeds on the interior of the grain kernel. The grub changes to a naked white pupa and later emerges as an adult beetle.

Adult grain weevils live an average of about seven to eight weeks. Each female lays 50 to 200 white eggs during this period. The female uses her strong mandibles to chew a small hole in the grain kernel where she deposits a single egg in the hole and seals it with a gelatinous fluid. In warm weather, the grain weevil can develop from egg to adult in about five weeks. Cold weather prolongs development. Adult grain weevils cannot fly so, they’re most likely to be found where grain is stored and move with the infested grain. The adults will also “feign” death by curling in their legs and antennae and falling to the ground, motionless, if disturbed.

How Did I get grain weevils

Wheat, corn, macaroni, oats, barley, sorghum, Kaffir seed, and buckwheat are just some of the grains and products on which these weevils feed. So, if you have any of those – that’s why they are there! High moisture and humidity can also not only attract grain weevils but be an ideal breeding ground for them. Proper moisture and temperature control as well as sanitation strategies inside and around facilities can help. Spillage piles outside of grain bins and warehouses can attract them to the facility and ultimately inside.

What Problems Do grain weevils Cause

These weevils are very destructive grain pests. Grain weevils develop as larvae within the grain kernels. They frequently cause almost complete destruction of grain in elevators or bins, where conditions are favorable and the grain is undisturbed for some length of time. Grain weevil infested grains will usually be found heating at the surface, and it may be damp, sometimes to such an extent that sprouting occurs. Wheat, corn, macaroni, oats, barley, sorghum, Kaffir seed, and buckwheat are just some of the grains and products on which these weevils feed.

HOW do i get rid of grain weevils

Prevention is the best strategy to avoid grain weevil problems in stored grains. Proper bin and warehouse sanitation before introduction of new grain minimizes the need for treatments. Good sanitation involves the removal of old grain and dust in and around the grain bin. This includes removal of old grain from corners, floors, and walls and grain that may have spilled on the exterior of the bin. Any grain remaining when a bin is emptied can harbor insect infestations which will move into the new grain. After the bin or warehouse is cleaned, and all needed repairs have been made properly seal the outer envelope of the facility. The floor and wall surfaces both inside and outside the bin should be treated by a professional. All inbound products should also be inspected and verified using the facility’s Sanitary Transport Rule program of the Food Safety Modernization Act.

Before grain is placed in a bin, it should be screened to eliminate fine materials and broken kernels. Grain placed in a clean bin should be checked at two-week intervals during warm months and at one-month intervals during cooler months for the presence of hotspots, moldy areas, and live insects. If any of these conditions exist, the grain should be aerated to lower the moisture level and temperature. If it has gotten out of hand, fumigation will take care of any immediate needs, getting you back to zero. This often will help in eliminating an existing problem while all the preventive tactics mentioned above get implemented to prevent future reinfestations.
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