جداسازی، تعیین توان بیماری زایی و دامنه میزبانی فوزاریوم های پاتوژن گل جالیز

In the summer of 2006, 18 isolates of Fusarium spp. were obtained from Egyptian broomrape (Orobanche aegyptiaca) in tomato fields in Karaj, Varamin and Golpayegan areas (Iran). In pathogenicity test of the isolates on Egyptian broomrape with stem puncture method, local symptoms were occurred after 3-4 days which finally resulted in wilting of the host plants 10-12 days after inoculation. The pathogens were re-isolated from infected tissues and each one was compared with its original culture. Among the pathogenic isolates, one of them was recognized F. equesiti and five other F. oxysporum. To evaluate the virulence of pathogenic isolates with soil inoculating method, three isolates reduced the number of Egyptian broomrape plants from 82.7 to 89.7 percent which were significantly more virulent than the other isolates. Host range test showed no symptom on tomato, soybean, red bean, chick pea, canola, sugar beet, sunflower, tobacco, cucumber, cucurbit, maize, wheat, barley, cotton, rape seed, alfalfa and clover when they were soil-inoculated with the selected isolates at 510ا 6 spores ml-1. The highly virulent isolates were selected for further investigation on microbial control of the parasitic weed.