Question

State one indicator each for infestation by insects and rodents in stored food grains. Describe one method each for controlling the population of insects and rodents.

Answer 1

Presence of cocoons, webs and weevilled grain indicates the infestation by insects.
Presence of excreta and holes in the bags indicates the infestation by rats.
Method of controlling insects in storage by fumigation : Fumigation is the-most effective method for controlling the insects without affecting the grains, e.g., ethylene dibromide. Depending on the quantity of grains to be fumigated, a certain number of EDB ampules wrapped in cloth are inserted a little below the surface of the grain and broken gently. The structure is left air-tight and undisturbed for a week. Toxic fumes diffuse and kill the insects.
Method of controlling rodents : Using single or multiple doses of rodenticide is the effective method of killing rodents.The, baits can be prepared by mixing flour of cereals with jaggery or sugar with edible oil and rodenticide in right proportion, .e.g, zinc phosphide.