Pathogenicity of Sclerotium spp. on common weeds in Meghalaya, India

Abstract

Sclerotium spp. are the major soil borne plant pathogens causing important plant diseases throughout the world. Two isolates SL 1 (Sclerotium rolfsii) and SU (S. delphinii) were used in pathogenicity test. Forty six common weeds (detached leaf and stem) were collected and used in pathogenicity test. Isolate SL1 (S. rolfsii) was pathogenic on both leaf and stem of all the common weeds except stem of Spilanthes paniculata. Isolate SU (S. delphinii) was pathogenic on both leaf and stem of all the common weeds. Incubation period on most of the common weeds was 1- 3 days except 6 days on Ageratum houstonianum and 4 days on Alternanthera philoxeroides, A. sessilis and Ischaemum rugosum with isolate SL1. Minimum days for sclerotia formation of SL1 isolate was 5 days on Emilia sonchifolia, maximum sclerotia production (38 nos.) was observed on Sonchus aspera. Incubation period on all the common weeds was 1- 3 days with SU isolate. Minimum days for sclerotia formation of SU isolate was 5 days on E. sonchifolia, Mikania micrantha and Urena lobata, maximum sclerotia production (46 nos.) was observed on Crassocephalum crepidioides. The weed A. sessilis was susceptible and U. lobata was most susceptible to isolate SL1 based on AUDPC. The weed A. houstonianum was susceptible and Commelina benghalensis was most susceptible to isolate SU.