Write the modes by which insects affect the crop yield?

Hint: There are various factors that affect the growth of a crop. Some of these are environmental like weather conditions but some are living like various kinds of pests. These act as barriers to getting the proper crop yield.

Complete answer:
There are two ways in which an insect harms a crop yield. One is the direct way in which it eats the leaves or damages the wood and the other is an indirect way in which it doesn’t harm the crop as much itself but leaves an infection behind like the fungal, bacterial or viral infection.

There exist various modes through which these insects make our life miserable causing a less crop yield-
Cutting- this is a direct as well as the most common way in which an insect affects the crop. It cuts the leaves, wood or the crop so that it can’t be used further. Such a type of crop becomes a waste as nobody wants to eat a half-destroyed crop. It is of no use in the commercial market as well as for the farmer too. Examples of such insects are leafhoppers, thrips, aphids etc.

Suckers- there are other kinds of insects too that suck the cell sap with the help of proboscis which ultimately damages the plant for further use leading to less crop yield. Examples of such insects are whitefly, bugs etc.

Boring- some pests utilize the nutrition from the plants, these are either fruit borers and stem borers. This pest burrows a specific part of a crop and uses it as a shelter. Examples of such insects are the deathwatch beetle, wharf beetle etc.

Note: Locust are one of the most dangerous pests and when present in millions they destroy the crop drastically. These pest effects to human health too either by creating famine due to less crop yield or by the infected crop yield.