The ecology of Chondrilla juncea in the western Mediterranean.
This study was conducted to examine the distribution of C. juncea in relation to various environmental conditions in the western Mediterranean where the plant occurs naturally. C. juncea was found to occur at low densities throughout much of the region with occasional areas of high density. The highest densities occurred following human disturbance, for example, in poorly cultivated and abandoned vineyards and in continuous cereal cultivation. Dense populations of C. juncea were also reported on sandy soils (up to 92.6% sand). Organisms that were found to damage or destroy the plant included the rust Puccinia chondrilla, the powdery mildews Erysiphe cichoracearum and Leveillula taurica, a gall mite Aceria chondrillae and the aphid Dactynotus chondrillae. It is concluded that the relative unimportance of C. juncea as a weed in the Mediterranean area is due mainly to local agricultural practices and soil conditions rather than to the prevalence of natural enemies. See also WA 18, 345 and WA 21, 2468-9.