نقش علف هاي هرز در پايداري Verticillium dahliae عامل پژمردگي آوندي پنبه در استان فارس

ROLE OF ALTERNATIVE HOSTS ON ACTIVITY AND SURVIVAL OF VERTICILLIUM DAHLIAE THE CAUSAL AGENT OF COTTON WITT IN FARS PROVINCE

During growing season 1997-98 several non-host plants including weeds and field crops were colected in cotton growing region of Estahban ( Khir fields) in wheat , sugarbeet and cotton fields and brought to the laboratory. Roots and stems were washed, surface sterilized with 0.5% NaOCI and plated on selective alcohol agar medium. From 48 non-hosts species, mostly weeds, Verticillium dahliae was recovered from stem of Hibiscus sp. and roots of Datura stramonium. Solatium nigrum and Anthium sp. grown under natural condition. Certain weed species grown in artificially infested soil with microsclerotia of cotton isolate of V. dahliae, showed that the pathogen could colonize stem of Solanum letum, S.nigrum, Medicago lupulina and Hibiscus sp. and roots of Amaranthus sp.. Datura stramonium, Xanthium sp. and Chenopodium quinoa.