Variability and Integrated Management of Anthracnose Colletotrichum lindemuthianum of French Bean

Abstract

newline Extensive surveys were conducted to assess the prevalence of french bean anthracnose in four important french bean growing districts of Jammu region (Jammu, Kathua, Rajouri and Udhampur). The overall disease severity ranged between 9.31-38.45 and 6.57-36.62 per cent, during the cropping season of 2021 and 2022, respectively. The disease severity showed positive and significant correlation with maximum and minimum temperature during both the cropping seasons. On the basis of pathogenicity test, twenty isolates of Colletotrichum lindemuthianum were grouped into three categories viz., highly, moderately and less virulent. The pathogenicity test (CL1-CL20) on cultivar Anupama recorded the disease severity ranging between 17.61-42.29 per cent. PDA medium recorded the best mycelial growth followed by CDA, OMA, RSA and FA while, poor mycelial growth was recorded on PCA medium. Twenty isolates were also classified into different categories on the basis of cultural and morphological characters viz., growth pattern, colony margin, colony colour, growth rate/day, size and shape of conidia. The isolates exhibited different shapes of conidia and the size of conidia ranged between 9.31-10.04×3.18-3.67 µm to 12.99-13.96×5.14-5.88 µm. Pathogenic variability of all the isolates revealed that CL16 designated as race 503 was found most virulent among all the other isolates. newlineOut of one hundred twenty two genotypes, thirty one genotypes were found to be moderately resistance whereas, fifty two and thirty nine genotypes were found moderately susceptible and susceptible, respectively. Among bio-control agents, Trichoderma harzianum was the most effective in inhibiting maximum mycelial growth (70.81%) of the pathogen. Among fungicides, Propiconazole was found significantly superior over all the other fungicides in inhibiting cent per cent mycelial growth of C. lindemuthianum. Under field conditions, seed treatment with Propiconazole at 2ml/kg of seed + two foliar sprays of Propiconazole at 0.1 per cent was the most effecti