A new silverleaf-inducing biotype Ms ofBemisia tabaci(Hemiptera: Aleyrodidae) indigenous to the islands of the south-west Indian Ocean

Abstract

AbstractFollowing the first detection of tomato yellow leaf curl virus (TYLCV) from R=union (700 km east of Madagascar) in 1997 and the upsurge ofBemisia tabaci(Gennadius) on vegetable crops, two genetic types ofB. tabaciwere distinguished using RAPD–PCR and cytochrome oxidase I (COI) gene sequence comparisons. One type was assigned to biotype B and the other was genetically dissimilar to the populations described elsewhere and was named Ms, after the Mascarenes Archipelago. This new genetic type forms a distinct group that is sister to two other groups, one to which the B biotype is a member and one to which the Q biotype belongs. The Ms biotype is thought to be indigenous to the region as it was also detected in Mauritius, the Seychelles and Madagascar. Both B and Ms populations ofB. tabaciinduced silverleaf symptoms onCucurbitasp., and were able to acquire and transmit TYLCV. Taken together these results indicate that the Ms genetic type should be considered a new biotype ofB. tabaci.