بيماريهاي قارچي گوجه فرنگي در استان خراسان شمالي و واكنش چهار رقم تجاري نسبت به آنها

FUNGAL DISEASES OF TOMATO IN NORTH KHORASAN PROVINCE AND THE REACTION OF FOUR COMMERCIAL CULTIVARS TO THEIR PATHOGENS

The North Khorasan province is an important tomato growing area in Northeast Iran. Fungal diseases of tomato studied with survey and sampling of diseased plants from 15 villages of this province in 2005 and 2006. Fungi isolated from diseased plants tissues and purified. Then, their optimum temperature for growth determined. Their inoculation to seeds and transplants of four commercial cultivars, Falat, Mobil, Super stran B and PS, and reisolation from diseased tissues, showed incidence of the diseases: Fusarium wilt (Fusarium oxysporum f.sp lycopersici), Fusarium root rot (Fusarium solani), Rhizoctonia root rot (Rhizoctonia solani) and Black mold (Alternaria alternata) in this province. All cultivars were susceptible to these diseases in seed germination stage, but transplants of some cultivars showed significantly resistance. Occurrence of these diseases in this province and reaction of cultivars is reported for the first time from Iran