. Elementary textbook of economic zoology and entomology. Zoology; Insect pests. INSECTS AFFECTING FIELD CROPS 4Q7. saturated with it, should be placed on top of the grain. As the gas that comes from it is heavy it will sink and reach all parts of the bin. Remember that this gas is inflammable and explosive. If the grain in the bins can be heated to 120° F. all the weevils in all stages of development will be killed. The Saw-toothed Grain-beetle (Silvanus surinamensis}.— Unlike the weevils, which are somewhat cylindrical, this small grain-beetle is quite flat. It may easily be recognized by th
. Elementary textbook of economic zoology and entomology. Zoology; Insect pests. INSECTS AFFECTING FIELD CROPS 4Q7. saturated with it, should be placed on top of the grain. As the gas that comes from it is heavy it will sink and reach all parts of the bin. Remember that this gas is inflammable and explosive. If the grain in the bins can be heated to 120° F. all the weevils in all stages of development will be killed. The Saw-toothed Grain-beetle (Silvanus surinamensis}.— Unlike the weevils, which are somewhat cylindrical, this small grain-beetle is quite flat. It may easily be recognized by the serrate margins of the prothorax. The larvae are long and slender and provided with six legs, enabling them to move about freely and thus injure several grains. The methods of control are the same as for the weevils. The Angumois Grain-moth (Sitotroga ccrealella).—In the south the grain-moth is even a worse pest than the weevils for it often occurs in almost incredible numbers and attacks wheat in the field as well as in the granaries. The moths fly from the storerooms while the wheat is heading, and lay their eggs on the grain. The larvae make their way into the kernels and become full grown about the time the wheat is mature. Other generations follow, the members of each attacking the grain wherever it is found, in the field, in the stack, or in store-rooms. Corn is not attacked as often as wheat, but seed corn stored in barns may often be badly injured. The grain should be threshed as early as possible and stored in tight bins or good sacks. If it becomes infested while stored, it may be treated with car- bon bisulphide. Cleanliness about the barns and particularly around the granaries is most essential. Badly infested grain may be fed to chickens or hogs. The Mediterranean Flour-moth (Ephestia kuehniella).— Mills are sometimes overrun with the larvae of a small grayish 32 FIG. 234.—Adult, pupa, and larva, of the saw-toothed grain- beetle, Silvanus surinamensis. (
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