Abstract
Abstract:
Galium spurium L. (Rubiaceae), native to Europe, is an increasingly serious annual weed of cultivated crops in the prairie provinces of Canada. The gall mite Cecidophyes rouhollahi Craemer (Acari, Eriophyidae), originally found on the related plant species Galium aparine L. in southern France, was evaluated as a potential biological control agent for G. spurium. In greenhouse tests, C. rouhollahi caused severe stunting and complete prevention of seed production by G. spurium. Host specificity tests showed that C. rouhollahi developed only on three closely related annual Galium species in the Kolgyda section. No native North American Galium species were attacked, with the exception of G. aparine. A review of available information on G. aparine suggests that it is probably an introduced species in North America. It has been reported that a related gall mite attacking G. aparine might be associated with a plant virus. A series of tests on a greenhouse colony of G. spurium infested with C. rouhollahi showed no evidence of viral infection. On the basis of these results, C. rouhollahi has been approved for field release against G. spurium in Canada. [ABSTRACT FROM AUTHOR]
