MORTALITY OF IMMATURE STAGES OF TRIALEURODES-VAPORARIORUM (HOMOPTERA, ALEYRODIDAE) ON REGAL GERANIUM, PELARGONIUM X DOMESTICUM

Preadult mortality and egg production by resulting adults of greenhouse whitefly, Trialeurodes vaporariorum (Westwood), were measured on 13 Pelargonium x domesticum cultivars and related to some plant characters. There was a significant effect of cultivars on the mortality of eggs, first to second instars, and total preadult mortality, but not that of third to fourth instars. Total preadult mortality was 2.6 times higher on the least suitable cultivar than the most suitable. Egg mortality was the most influential component shaping total preadult mortality according to the cultivar. Total mortality in each cultivar was significantly and inversely correlated with adult preference, so that the cultivars less preferred by females for oviposition were also less suitable for the survival of progeny. In the mortality-plant character relationship analysis only egg and total mortality were significantly and positively correlated with leaf-soluble glucose content. The cultivar variable also affected egg production by adults that emerged from larvae developed on them, but it could not be correlated with any of the plant characters measured.