Determination of Pathogenicity of Choanephora cucurbitarum (Berkeley and Ravenel) Thaxt, Amongst Commonly Cultivated Vegetables in Calabar, Cross River State, Nigeria

Abstract

Choanephora cucurbitarum is a plant pathogenic fungus with a wide host range. The fungus was isolated from rotting fruits of Capsicum anuum, after it was observed that some vegetables were infected in the farm. The role of infection courts on severity was determined by inoculating the pathogen into soil, leaves and stems of the test plants. The test plants used were Abelmoschus esculentus, Amaranthus sp, Cucumis sativus and Vigna unguiculata. Determinants of pathogenicity were plant height, leaf reduction, fresh and dry weight. Results showed that the fungus was pathogenic to the test plants. A significant reduction in height, leaves, fresh and dry weight of the test plants was observed when compared with the control. The greatest effect of the pathogen was on the inoculated stem of the test plants with a mean of 42.94. The least effect was observed on infected soil with a mean of 92.99. Cucumis sativus showed the least effect by the pathogen with a mean of 84.18, while Abelmoschus esculentus showed the greatest effect with a mean of 44.59. The pathogen showed the greatest effect on leaves of Cucumis sativus with a mean of 20.45, while the least effect was on Vigna unguiculata with a mean of 36.77.Fresh weight ranged from 3.35g to 37.40g, Dry weight 2.15 to 7.90g as compared with the control which had a fresh weight of 7.0g to 57.25g and 3.8g to 11.90g for dry weight. Symptoms such as leaf blight, blight of the shoot apex, soft rot of stems, die back and decay of Vigna unguiculata pods were observed.