Host-plant susceptibility to the carrot fly, Psila rosae. 3. The role of oviposition preferences and larval performance

The acceptability of various plant species to ovipositing carrot flies was weakly, but significantly correlated with the host's suitability for larval development. Both adult host-plant preferences and larval performance as d etermined in laboratory experiments explained a part of the variation in su sceptibility among the various test plants observed in the field. Across th e whole set of plant species examined, antixenosis contributed more substan tially to resistance than antibiosis, while the reverse seemed to be true f or carrot cultivars.