Concept:Insects that damage crops by biting and chewing possess strong mandibles used for cutting and grinding plant parts.
Sucking pests, such as whiteflies and mealybugs, use piercing-sucking mouthparts, so they are excluded from this group.
Explanation:Armyworms are leaf-eating caterpillars that bite and chew crop leaves.
Termites are chewing insects that attack roots, stems, and wooden plant tissues.
Grasshoppers are typical chewing pests that consume large portions of leaves and stems.
Crickets also chew, but cotton stainer, mealybug, and whitefly feed by piercing and sucking sap.
Thus, option A and B contain sucking insects, and option C includes cotton stainer, which is not a chewing pest.
The only group where every insect is a biting and chewing pest is armyworm, termite, and grasshopper.
Answer:D. Armyworm, termite and grasshopper