SUMMARY

Dialeurodes citri (Hom. Aleyrodidae) first invaded citrus orchards in the South Adriatic, near Dubrovnik, during 1977. Since the characteristics of the pest have not been studied in Croatia, this paper reviews its morphology, locations, host plant range and biology. Leaf samples, collected all over the Croatian coast and islands, were observed in the laboratory for purpose of creating a map with citrus whitefly locations, morphological description and a list of host plants. The pest biological cycle and population trend were investigated in the region of Split (May 1996-May 1998). The presence of citrus whitefly was confirmed in all citrus-growing areas of Croatia. The number of noted host plants was somewhat lower than in Mediterranean countries. Other than citrus, it also colonised and harmed laurustinus (Viburnum tinus Hemsl.), persimmon (Diospyros kaki Thunb.) and several plants of Oleaceae. The citrus whitefly had three generations on citrus per year. However, the part of larval population that belonged to second generation did not finish the post-embryonic development and it remained on the summer flush leaves and awaited the hibernation. The appearance of adults followed the appearance of young citrus growth. All development stages had three population peaks during vegetation period. The presence of young larval stages (L-1, L-2) was pronounced during the middle of June, August and October. The pest overwintered mainly as fourth instar larva. On deciduous persimmon trees it had two generations per year