BIOLOGY OF Colletotrichum capsici AND MANAGEMENT OF ANTHRACNOSE OF CHILLI

Abstract

Four isolates of Colletotrichum capsici infecting chilli in four major growing areas of Bangladesh were collected and purified to characterize in terms of cultural, morphological, physiological and pathogenicity. Another field experiment was conducted to search out a suitable management option against anthracnose disease of chilli. Five treatments viz. planting in raised bed, space planting (50x50cm), Micro tech-1 @ 10ml/L water, Metaril 72 WP @ 2g/L water and Control were applied. The isolates varied significantly in their cultural, morphological and pathogenic traits- viz. colony color, shape, margin, texture and production of conidia. The optimum temperature and pH for the radial mycelial growth of Colletotrichum capsici were recorded at 25-30°C and pH 6.0-6.5, respectively. No growth was observed at 10°C and 35°C temperature. Excellent (++++) sporulation was recorded at temperature 25 and 30°C and pH 6.0 and 6.5 for all the isolates. The pathogen Colletotrichum capsici grew well on PDA medium. The highest (87.00 mm) radial mycelial growth was obtained on PDA. Good (+++) sporulation was recorded at CDA media for all the isolates. No growth and sporulation was found in V-8 A and WA media. The length of conidia varied from 9.9-51.8μm. Mean length of conidia was maximum 28.40 μm in isolate BoCC-1 and minimum 2.88 μm in isolate PaCC-1. The breadth of conidia ranged from 0.33-12.40 μm. The highest mean breadth 4.56 μm was observed in isolate BoCC-1 and the lowest 2.88 μm in isolate PaCC-1. The highest disease score was found in Isolate BoCC-1 and RaCC-1 in case of red (7.00) and green (5.00) chillies, respectively. On the other hand, the lowest disease score was found in Isolate GaCC-1 and PaCC-1 in case of red (5.00) and green (3.00) chillies, respectively. The lowest plant infection (25.45%) and highest yield (456.3 g plant -1 ) was obtained from planting in raised bed followed by application of Metaril 72 WP @ 2g/L water.