NEW RECORD OF Podosphaera xanthii ON Ageratum conyzoides L. IN PAKISTAN

Powdery mildew fungi are one of the important pathogens and cause a significant damage in various plants. ageratum conyzoides l. is a widespread perennial weed having important medicinal and biocontrol properties. in april 2012, a severe outbreak of powdery mildew was observed on a. conyzoides. powdery mildew symptoms were mainly observed on stem and both sides of young and mature leaves, but not on floral parts. on the basis of morphological characters, the fungus was identified as a podosphaera xanthii. pathogenicity test was conducted in green house at 22°c and 80% rh and seven days after inoculation, white powdery mildew colonies appeared on the leaf surface. fungal colony was reexamined for the confirmation of pathogen. this is the first report of p. xanthii on a. conyzoides in lahore, pakistan.