Californian thistle (Cirsium arvense L. Scop.) is a pest to the organic pea industry because flower buds may be accidentally harvested and are difficult to remove during processing. The Californian thistle gall fly (Urophora ...

Cirsium arvense (Californian thistle) is a problematic weed in agricultural systems throughout New Zealand and the rust fungus Puccinia punctiformis is a potential biological control agent for this weed. Puccinia punctiformis ...