Prevalence and distribution of Fusarium leaf spot of Plumbago zeylanica caused by Fusarium chlamydosporum in Bhadra Wildlife sanctuary in Karnataka.

摘要

Plumbago zeylanica, commonly known as 'Chitrika', is an important endangered medicinal herb used extensively in ethnomedicine. Studies were conducted to determine the causal agent of a foliar disease affecting P. zeylanica plants in Bhadra Wildlife sanctuary during 2006-2009. The incidence and severity of foliar fungal disease in forest regions as well as the distribution pattern of disease in the sanctuary was determined. Diseased foliage samples were analyzed for certain secondary metabolites. The causal agent of the foliar disease was identified as Fusarium chlamydosporum in the samples collected from Lakkavalli, Kemmannugundi and Kakanahosudi state forests of the sanctuary. The incidence and severity of the disease was high in Lakkavalli forest during the December-March period. The pathogen was evenly distributed in all the three forest regions. Analysis of the diseased foliage samples indicated the presence of alkaloids, such as flavonoids and phenols which increased with increase in infection due to F. chlamydosporum, while the levels of steroids decreased. The study also revealed that the leaf spot became severe during winter months which altered the secondary metabolite content in infected foliage.