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CHOANEPHORA POD ROT OF PIGEONPEA IN PAKISTAN

S.M. IQBAL, S. HUSSAIN, H.R. KHAN AND B.A. MALIK

Abstract: Extra early pigeonpea genotypes selected from ICRISAT materials planted at the National Agricultural Research Centre, Islamabad were found infected by a pod rot disease during September-October, 1990. The disease appeared as water soaked lesions which subsequently developed into a wet rot affecting both young and mature pods showing luxuriant whitish growth with black headed pin like sporangia around the pods. The pods damaged by insects were more affected than non-damaged pods. Withered and detached flowers also showed fungal growth. Pods near maturity were more susceptible than the young pods specially under humid conditions. The fungus isolated in pure culture on PDA medium was identified as Choanephora cucurbitarum (Berk and Rav.) Thaxter (Stevens, 1913). Detached healthy pods of pigeonpea cultivar ICCP-83015 surface sterilized with 0.5% sodium hypochlorite solution for 1.5 minutes, followed by washing in sterilized distilled water were dipped in a conidial suspension of C. cucurbitarum (6.5x10⁴ conidia/ml) and placed in sterilized Petri plates at room temperature (24±2°C) developed characteristic symptoms of the disease. There does not appear to be any previous report of C. cucurbitarum on pigeonpea in Pakistan. Pod rot of pigeonpea caused by C. cucurbitarum has been reported from India (Misra & Mehra, 1969). The fungus has been reported to parasitize Luffa acutangula Roxb., (Ghaffar & Kafi, 1968), Capsicum annum L., (Mirza & Qureshi, 1978), Vigna unguiculata (L.) Wilp (Bashir et al., 1985) and Vigna radiata (L.) Wilczek (Alam et al., 1984).

Pulses Programme, National Agricultural Research Centre, Islamabad, Pakistan.