PELARGONIUM CULTIVAR SELECTION BY ADULTS OF GREENHOUSE-WHITEFLY (HOMOPTERA, ALEYRODIDAE)

Thirteen local Pelargonium x domesticum cultivars were evaluated for greenhouse whitefly, Trialeurodes vaporariorum (Westwood), preference. Some morphological and physiological characteristics of these cultivars were measured to determine their influence on greenhouse whitefly adult preference. Host plant characteristics and greenhouse microclimate accounted for 37.8 and 11.8% of the total whitefly adult distribution variability measured 62 h after the adults had been released. In the variability accounted for by the host plant, 26.5% was attributed to differences between cultivars and the rest (8.0%) to the leaf developmental stage. Hairiness and leaf size were correlated with whitefly adult distribution; the less hairy ones and those with larger leaves were the preferred cultivars. The other host plant characteristics that were measured (thickness of adaxial epidermal cuticle, fresh-dry weight relationship, and soluble sugars and protein) were not related to greenhouse adult preference. Egg laying was not significantly different in each cultivar.