Efficacy of Three Selected Botanicals in the control of Botrytis cinerea Associated with Damping Off in Citrullus lanatus (Thunb.) Matsum and Nakai.

Abstract

The use of plant extracts in controlling plant diseases has witnessed appreciable success; such was exploited in this study when efficacy of extracts from Azadirachta indica, Calotropis procera and Anacardium occidentale, each at different concentrations; 30 mg ml-1, 60 mg ml-1, 90 mg ml-1 and 0 mg ml-1 (Control), were examined in vitro to control Botrytis cinerea that causes damping off disease of Citrullus lanatus var. ‘lanatus’. Result showed that the mean inhibition in colony diameter at 90 mg ml-1 ranged from 0.26-2.26 (A. indica), 0.43-3.30 (C. procera) and 0.13-2.50 (A. occidentale) compared respectively to 0.5-4.36, 0.57-4.33 and 0.43-4.10 in their 0 mg ml-1 concentration. The 90 mg ml-1 concentration that has the least fungal growth evident at different days in all extract used was significantly different (p≤0.05) from the 0 mg ml-1. Furthermore, percentage inhibition in A. occidentale (37.50%) and A. indica (43.33%) were slightly significant (p≤0.05) at 90 mg ml-1 concentration but was significant (p≤0.05) in C. procera (17.50%). From this study, it can therefore be recommended that field trial of these medicinal plants on the control of damping off disease caused by B. cinerea can be achieved as the concentration of the extracts used here increases. Also, the use of these extracts should be inculcated as part of cultural control measure, since they are easy, simple and cost-effective in making.