Characterisation and in-vitro Control of Curvularia lunata , the Causal Agent of Brown Leaf Spot Disease of Rice in Ghana

Abstract

Irrigated rice production is common in the coastal savannah zone of Ghana. Recent observations have shown the incidence of a new leaf spot disease in some rice basins in the area. Research was carried out to determine the incidence and severity of the disease in the area, identify the causal agent using its cultural and morphological features, complemented with phylogenetic studies of the internal transcribed spacer region. Also, the effect of some selected fungicides and an antagonistic Trichoderma harzianum on the mycelial growth of the fungus was determined in vitro. The disease was found in all the major rice growing districts in the coastal savannah zone with severities ranging from 22.6 to 50.9%. Curvularia lunata was identified as the causal agent of the disease. Carbendazim, Nordox and Mancozeb, totally depressed the mycelial growth of the fungus whiles T. harzianum inhibited the growth of the fungus. These fungicides and antagonistic organism have the potential for the control of the disease in the field.