canada thisle is one of serious weeds throughout the world and third serious weed in Europe. the control of this weed is very difficult due to its extensive lateral and diffused root systems, the lignified and spiny form of its stem and leaves and also the ability of high seed production. canada thistle seriously decrease crops yield. this study as started from 2006 and so far 12 branches arthropod contain a mite herbivore belonging to Arachnida and 12 species belonging to coleoptera have been found. among these agents, cassida rubiginosa species showed high population and efficiency on canada thistle and therfore this species can be a promising biological control agent for canada thistle.

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