HOST SPECIFICITY OF ALTICA CARDUORUM GUER. (COLEOPTERA: CHRYSOMELIDAE)

Abstract

The flea beetle Altica carduorum Guer. could be reared only on plants of the closely related genera Cirsium, Silybum, and Carduus. The relative acceptability of the different species within this group was correlated with the closeness of their taxonomic relationships to Cirsium arvense (L.) Scop. It is concluded that, in the field, the beetle will be restricted to attacking a few species of Cirsium and will not endanger any economic plant in North America. Thus it is a suitable insect to be used for the biological control of C. arvense in North America. Results of preliminary liberations of A. carduorum are insufficient to indicate if it will exert effective control of the weed in Canada.