ABSTRACT
Biological control of weeds is the use of phytophagous natural enemies to reduce the population densities of target weeds. The most important approach to biological control of weeds has been the classical, or importation method, which is the introduction of natural enemies from the area of origin of the target weed. Many tephritid enemies of weeds have this requisite high degree of host specificity, and are employed as classical biological control agents. Biological control projects have stimulated many studies on the biology and ecology of Tephritidae. Many biocontrol tephritids for weedy Asteraceae attack capitula. There was a modest weed biocontrol participation of two papers in this Symposium. This reflects the Symposia’s historically primary interest in frugivorous tephritid pests. A considerable number of biocontrol tephritids induce gall formation in the attacked capitula or stems of their host plants, and as noted in A. Freidberg’s review of gall inducing Tephritidae, they are the second most notable cecidogenous family of Diptera.
