Concept:Cassava mosaic disease is a viral disease spread by a whitefly vector.Explanation:• The disease is caused by cassava mosaic virus.• It is transmitted by whiteflies of the genus Bemisia, especially Bemisia tabaci.• Among the options, only Bemisia nigerensis belongs to the whitefly group that transmits cassava mosaic.• The other insects are crop pests but not vectors of cassava mosaic virus.Answer:D. Bemisia nigerensis