MORPHOLOGICAL VARIATION IN PLANOCOCCOIDES NJALENSIS OCCURRING ON COCOA IN GHANA

A study was made to determine the extent of morphological variation in Planococcoides jalensis (Laing), the most important mealybug vector o f cocoa swollen shoot virus (CSSV) in West Africa, and to resolve if m ore than one Planococcoides species is present. Fourteen populations o f P. njalensis collected on cocoa from different localities in Ghana a nd one population each on Gliricidia sepium (Jacq.) Steud and Coffea c anephora Pierre were compared by measured and meristic female characte rs using two types of morphometric analysis, Discriminant Functional A nalysis and Principal Component Analysis. The analyses showed that P. njalensis exhibited a wide range of intraspecific morphological variat ion, particularly in meristic characters, but failed to identify new P lanococcoides species. The results are discussed in relation to the co ntrol of the mealybug vectors of CSSV and to the suitability of Gliric idia as a shade tree for cocoa.