MITOCHONDRIAL DNA VARIATION OF BEMISIA TABACI (GENNADIUS) (HEMIPTERA: ALEYRODIDAE) INFESTING CASSAVA IN KENYA

Abstract

Bemisia tabaci is a widely distributed crop pest affecting the yield of a broad range of agricultural, fiber, vegetableand ornamental crops. It is an extremely polyphagous pest that causes direct damage and can act as a vector ofviral plant diseases. Populations of Bemisia tabaci that are morphologically indistinguishable and with differentbiological traits have been known to exist; they show differences in rates of development, host range, insecticideresistance and virus transmission efficiencies. The objective of this study was to investigate the biotype identity ofB. tabaci infesting cassava in Kenya using the mitochondrial cytochrome oxidase I (mtCOI) sequence as a molecularmarker. The mitochondrion cytochrome oxidase one gene fragments were phyologenetically analyzed usingneighbor joining method. Results revealed two distinct haplotypes of cassava associated B. tabaci in Kenya. Thefirst haplotype consisted B. tabaci collected from the Eastern and Coast provinces of Kenya in a sub-cluster with 68boot strap value. They closely resembled B. tabaci genotypes from the southern parts of Africa (Mozambique,South Africa, Swaziland and Zambia) and B. tabaci isolate from West Africa (Ghana). The second haplotypecomprised of B. tabaci collected from cassava growing regions in Nyanza and Western provinces of Kenya in a subclusterwith 94 boot strap value. They shared close sequence homology with cassava B. tabaci from Uganda andTanzania. The findings of this study form part of important documentation on B. tabaci biotype status in Kenya forpest management purposes and for the prevention of invasive biotypes which may be more dangerous.