Performance evaluation and host range of seed fly Urophora xanthippe (Dipt.: Tephritidae) in order to biologically control of weeds crap in Birjand

To evaluate the efficiency of head flies Urophora xanthippe (Dipt.: Tephritidae) in control of knapweed through the destroying of seed, three experiments was conducted separately in the field, greenhouse and laboratory condition at University of Birjand in 2010. The first experiment was conducted for evaluation of the ability of U. xanthippe to the destroying of seed andreducing of the number of knapweed seed. Other experiments carried out to determination of host range and preference of insect. The results showed that the average of seeds in attacked boll (6.35 ± 0.01) had significant difference with no attacked boll (11.83±0.01), in treated plants. Also, the mean number of seeds (including seeds intact and damaged) had significant difference between the treated plants (11.82±1.02) and the control (29.77±1.02). The results of this study showed that the attack of U. xanthippe causes 64.00±0.01 destroying of knapweed seeds in natural conditions. Due to the high potential of U. xanthippe in reducing the number of seeds and also, a limited host range, it can be used as a biological control agent of knapweed in the integrated management of this weed species.