Carpogenic germination of Sclerotia of Sclerotiniasclerotiorum (Lib.) de Bary and development of an IDM modules for management of Sclerotinia rot of French bean
Loading...
Date
2015
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
AAU
Abstract
Studies conducted on morphological and pathogenic variability among 30 isolates of Sclerotiniasclerotiorum (Lib) de Bary, derived from infected French bean (Phaseolus vulgaris) plants showing typical symptoms of white mold, collected from different geographical location of NE. All the isolates showed variation in morphological characters based on their mycelial growth, colony character and sclerotial formations. Out of 30 isolates, 14 isolates showed highly virulent reaction, each of 8 isolates revealed moderately and less virulent reaction respectively on French bean. HPLC analysis of mycelial culture extracts of highly, moderately and less virulent isolates from S. sclerotiorum showed that higher number of phenolic acid and higher concentration of oxalic acid were observed in highly virulent isolates of S. sclerotiorum , while lowest number of phenolic acids and least conc. of oxalic acid detected in less virulent isolates. In in vitro study of growth of highly virulent isolates of S. sclerotiorum against fungal antagonists showed that T. harzianum caused maximum inhibition of radial growth of S. sclerotiorum among the antagonists. Maximum growth and least per cent inhibition of radial growth by different antagonists was observed in AS3 (Assam) isolate of S. sclerotiorum.
Effect of burial depth, soil drenching with Carbendazim and mycoparasites on carpogenic germination of Sclerotia of S. sclerotiorumwere evaluated under pot condition. It was observed that higher number of apothecia were produced when Sclerotia placed at ‘0’cm depth, while no apothecia were found at deeper depths viz,.6, 8 and 10cm respectively. Soil application of Carbendazim were more effective when applied 10 days after burial as compared to application at ‘0’ day of burial in inhibition of carpogenic germination of Sclerotia and there was a decreased sclerotial germination with increased concentration of fungicide. Amongst the antagonists, T. harzianum was found to be the most effective agent and caused highest reduction in carpogenic germination of Sclerotia followed by G. virens and T. koningii respectively.
Under field condition, maximum reduction of white mold incidence and higher growth response and yield were observed when seeds were treated with Carbendazim @ 0.2% and it was integrated with soil application of T. harzianum @ 2%(w/w) of soil and Carbendazim spray @ 0.1% at 15 and 30 DAG in FYM amended soil as compared to other treatment combinations.