In vitro Evaluation of Biocontrol Agents against Leaf Spot Disease of Okra Caused by Cercospora sp.

Abstract

Okra (Abelmoschus esculentus) is an important vegetable crop that cultivated in tropical and subtropical regions of the world. It is mostly grown for its delicate fruit, stem, flower and bud. Like other crop, okra is also attacked by many diseases. Among all diseases, leaf spot is major disease which causes heavy loss to the crop. During isolation and identification it was identified as Cercospora and varied in their cultural and morphological character. Pathogenecity test was also proved by using Koch’s postulates. During course of study, 4 bio control agents were evaluated under in vitro condition for their effectiveness. Among all bio control agents Bacillus subtilis showed maximum inhibition at different time intervals of 68.14 %, 76.00 %, 81.17 % at 72 hrs, 120hrs, 168 hrs respectively followed by Trichoderma harzianum with 66.02 %, 72.27% and 77.25 % respectively at 72hrs, 120 hrs, 168 hrs. Similarly other bio control agents –Trichoderma asperellum and Pseudomonas fluorescens were also found effective with inhibition of 62.60 %, 70.74%, 76.24% and 60.20%, 69.45%, 75.05% respectively at 72hrs, 120hrs, and 168hrs. The result from present investigation revealed that Bacillus subtilis was found most effective in the suppression of pathogen growth. In future investigations, this bio-control agent might be further assessed for the effective treatment of okra leaf spot disease.