Geographical distribution and host range in Nigeria of the mango mealy bug, Rastrococcus invadens Williams, a serious exotic pest of horticulture and other crops

Abstract

The geographical distribution and host range in Nigeria of the mango mealy bug, Rastrococcus invadens Williams (Hemiptera: Pseudococcidae), a serious exotic insect pest of mango and many other crops is reported. The spread of R. invadens in Nigeria is at present limited to Lagos, Ogun and Oyo States of the humid south-west contiguous with the Republic of Benin, where the incidence of the pest has previously been reported. Infestation has not been observed in any of the 11 states of the north nor in the Federal Capital Territory all of which have lower rainfall and relative humidity. R. invadens is highly polyphagous on over 20 species of host plants in 12 different plant families ranging from fruit crops which constituted 42.85% of the crops attacked, to food crops (14.28%), and to shade trees and ornamentals (42.85%). Severity of attack which was based on the number and area of foliage, Inflorescence and fruits attacked by R. invadens alone or together with sooty mould was highest in mango, citrus, breadfruit, guava and ornamentals including oleander, frangipani and roses. Hosts with mild infestation include maize, pawpaw and croton. The frequency with which infested plants are being felled, burnt or sprayed with synthetic chemicals suggests the panic which R. invadens attack has caused to growers.