Occurrence and distribution of Colletotrichum disease of cocoa in South India
Among the diseases of cocoa (Theobroma cacao L.) recorded from India, only Phytophthora diseases (Phytophthora palmivora (Butl.)Butl.), leaf spot and pod rot (Colletotrichum gloeosporioides -(Penz.) Sacc;) and charcoal pod rot (Botryodiplodia theobromae Pat.) were found to be the major ones. C. gloeosporioides causes three types of foliar symptoms viz. leaf blight, shot hole and irregular leaf spot, and pod rot of cherelles and young pods. Leaf blight was found in all the districts surveyed. Shot hole was not observed in Alleppey and Idukki districts of Kerala and Bangalore and Tumkur districts of Karnataka. But irregular leaf spot was observed only in three districts of Karnataka. Pod rot was found in all the districts surveyed except Idukki district. Out of 101 gardens surveyed, the frequency of occurrence of leaf blight was maximum (78 per cent) followed by shot hole (42 per cent) and irregular leaf spot (12 per cent). Pod rot was noticed in 60 per cent of the gardens surveyed. The distribution of disease symptoms was also found to be affected by cropping patterns. Incidence of leaf blight was found to be more prominent under heavily shaded conditions. On the other hand shot hole incidence was mostly observed in cocoa-coconut mixed gardens and cocoa pure gardens where the shade is comparatively less. The incidence of irregular leaf spot and pod rot did not show much variation in relation to cropping patterns. Incidence of foliar symptoms and pod rot was more in gardens of lower altitudes (0-120 m). From the present study, it can be inferred that Colletotrichum disease of cocoa, except irregular leaf spot, is widespread in the major cocoa growing areas of India and is likely to occur in epiphytotic proportions in the near future.
| Main Authors: | , |
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| Format: | biblioteca |
| Published: |
1983
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| Subjects: | THEOBROMA CACAO, COLLETOTRICHUM GLOEOSPORIOIDES, ENFERMEDADES FUNGOSAS, SINTOMAS, DISTRIBUCION NATURAL, MORBOSIDAD, INDIA, |
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