The status of Bemisia tabaci (Hom.: Aleyrodidae), Trialeurodes vaporariorum (Hom.: Aleyrodidae) and their natural enemies in Crete

The non «B» biotype of Bemisia tabaci (Gennadius) is recorded for the first time in Crete in 1992, in the north east and south east of the island. Trialeurodes vaporariorum (Westwood) is the predominant whitefly on plants in the north and west of the island. Three surveys of Crete were made in 1992 and 1993 for natural enemies of B. tabaci and T. vaporariorum and resulted in the collection of 4 species of Encarsia, (plus a number of species that are unidentifiable at this time), an Eretmocerus sp. (unidentifiable at this time) and a fungal pathogen, Paecilomyces farinosus (Dickson Ex Fries) Brown & Smith. Encarsia adrianae was identified from T. vaporariorum; which constitutes its most westerly distribution point and a new host record respectively. B. tabaci and T. vaporariorum were found on horticultural crops, ornamentals and weeds. Populations of both whitefly species were severely depleted on field hosts throughout the island during the winter of 1992/93. Climatic constraints, competition with T. vaporariorum in otherwise suitable niches, effective natural enemies and an observed low level of polyphagy may explain the present limited distribution of the non «B» biotype of B. tabaci in Crete.