Question

How do insect affect the crop plant? How are they protected ?

Answer 1

Insects are responsible for two major kinds of damage to growing crops. First is direct injury done to the plantby the feeding insect, which eats leaves or burrows in stems, fruit, or roots. There are hundreds of pestspecies of this type, both in larvae and adults, among orthopterans, homopterans, heteropterans, coleopterans, lepidopterans, and dipterans. The second type is indirect damage in which the insect itself does little or no harm but transmits a bacterial, viral, or fungal infection into a crop. Examples include the viral diseases of sugar beets and potatoes, carried from plant to plant by aphids.

Today, dependable crop yields are obtained by using disease-resistant varieties, biological control practices, and by applying pesticides to control plant diseases, insects, weeds, and other pests. 

Answer 2

Insects eat up the plant leafs and disturb the fertility of the soil. To protect them,farmers use spray fertilizers to stop them and protect plants.