Seasonal Abundance of Russian Knapweed Seedhead Fly, Urophora xanthippe (Dip: Tephritidae) and Identification of its Parasitoids in Cold Semi-Arid Climate

Resumen

Russian knapweed (Acroptylon repens (L.) de Candolle) is a perennial plant and a native of Eurasia which is now spread in many parts of the world. It is essential to control this weed as it competes with crops for vital resources, which results in significant losses. Russian knapweed head flies (Urophora xanthippe) have been reported as one of the biological control agents of this species in Iran. In this study, adult head flies were captured using yellow sticky traps, and their gender was recorded. To investigate the potential parasitoids coincided with the start of each generation, 100 bolls of spotted knapweed were put in a box closed with mesh 1 % mm (20×15×15cm) and put in a growth chamber at 25 ± 1°C, 65 ± 5% RH and 16:8 h L:D.. Results showed that the gross and net fecundity rates were significantly different on rose cultivars. Species collected were sent for identification to the Iranian Research Institute of Plant Protection. Based on these results, the insects density occurred in nature from early May to early July. Evidence indicates that head fly density rises in nature from 5 June. In the weather of Birjand, the Density of head flies was maximized from 10 May to 25 June in Birjand. The peak appearance of head flies coincides with the emergence of the second generation. Two Hyperparasites pupae were identified as Microdontomerus annulatus (Spinola) and Eurytoma sp. belonging to the Torymidae and Eurytomidae family. Based on the information provided, it may be possible to find a more optimal time to use insecticide to control Acanthiophilus helianthi Rossi, which does not coincide with the peak flight of U. xanthippe.