Jatropha curcas (Physic nut) is a potential plant source for production of biofuel. The growing concern over global warming and climate change due to CO emissions from fossil fuel has roused global attention towards renewable, 2 more environmentally friendly alternative sources of energy. Anthracnose disease caused by Colletotrichum species is one of the most wide spread plant diseases in the tropics. We investigated the causal pathogen of Jatropha curcas anthracnose in South-western Nigeria. Samples were collected from seeds and diseased seedlings of four J.curcas accessions raised at the Forestry Research Institute of Nigeria nursery under natural infection. Culturing and isolations from the samples were carried out at the Plant Pathology laboratory of Crop Protection and Environmental Biology. Cultural and morphological characters of the fungi were observed. Pathogenicity of the isolate was confirmed on J. curcas seedlings. The experiment was carried out in a Randomized Complete Block Design (RCBD) with five replicates. Data were collected on disease intensity (incidence and severity). Evaluation of disease incidence (%) and severity (1-5, ranging from no disease to highly susceptible) were calculated and data were analysed using Analysis of Variance (ANOVA) and significantly different means were separated using LSD at 5% (p ≤0.05) level of significance. Colletotrichum species, was identified to cause anthracnose on four Jatropha accessions, causing symptoms with high disease intensity on the plants; anthracnose (29.0%), cankers (41.4%), shoot dieback (79.4%). The susceptibility of Jatropha accessions to anthracnose caused by the fungus, Colletotrichum gloeosporioides (Penze.) Penze & Sacc was confirmed. To maximize yield of this oil plant and sustain the new hype in its cultivation for biodiesel production, anthracnose disease ought to be effectively managed.
Key words: Accessions, Biodiesel, Cankers, Global warming, Pathogens.