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Morphological variation in Planococcoides njalensis occurring on cocoa in Ghana

Padi, B., Hollander, J.
Entomologia experimentalis et applicata 1996 v.79 no.3 pp. 317-328
Cacao swollen shoot virus, Coffea canephora, Gliricidia sepium, Planococcoides njalensis, females, morphometry, principal component analysis, trees, Ghana
A study was made to determine the extent of morphological variation in Planococcoides jalensis (Laing), the most important mealybug vector of cocoa swollen shoot virus (CSSV) in West Africa, and to resolve if more than one Planococcoides species is present. Fourteen populations of P. njalensis collected on cocoa from different localities in Ghana and one population each on Gliricidia sepium (Jacq.) Steud and Coffea canephora Pierre were compared by measured and meristic female characters using two types of morphometric analysis, Discriminant Functional Analysis and Principal Component Analysis. The analyses showed that P. njalensis exhibited a wide range of intraspecific morphological variation, particularly in meristic characters, but failed to identify new Planococcoides species. The results are discussed in relation to the control of the mealybug vectors of CSSV and to the suitability of Gliricidia as a shade tree for cocoa.