WAEC Agricultural Science 1992 Theory question 105

Any eight: reduce yield by eating leaves, stems, roots; reduce quality and market value of produce; transmit diseases (e.g. aphids carry rosette virus); cause death of plants; increase cost of production (pesticides, labour); damage stored produce; create wounds for disease organisms; reduce viability of seeds; cause loss of income/food shortage; some are useful (pollinators, natural enemies, silk, honey)

Mostly harmful effects; a beneficial point may be added.