Pest

A fatal epidemic disease; a pestilence; specif., the plague.

Anything which resembles a pest; one who, or that which, is troublesome, noxious, mischievous, or destructive; a nuisance.

any unwanted and destructive insect or other animal that attacks food or crops or livestock etc.; "he sprayed the garden to get rid of pests"; "many pests have developed resistance to the common pesticides"