Bio activity of some botanicals on Helminthosporium infestans L. and Solanum aethiopicum L. (host)

Some botanicals were assayed in two laboratory trials for their relative toxicities to African eggplant (Solanum aethiopicum L.) and Helminthosporium infestans causing leaf spots disease at the Department of Crop Science, University of Nigeria, Nsukka. In the first experiment on the toxicity of the protectants to S. aethiopicum, three concentrations (10, 20 and 30 g/ml) were used. Four concentrations (0.03, 0.06, 0.12 and 0.25 g/ml) were used in the second experiment on the toxicity of the botanicals (Azadirachta indica leaves, Gongronema latifolia leaves, Garcinia kola seeds, Zingiber officinale stems and Carica papaya leaves) to H. Infestans. Distilled water served as control in each case. Solanum seeds dressed with G. kola germinated faster and attained 100% germination 14 days after incubation (DAI). On the other hand, Z. officinale inhibited the seed germination most, resulting in the least germination being recorded on seeds treated with Z. officinale. Similarly, all the plant extracts assayed inhibited the growth of H. Infestans to varying degrees relative to check at 3 days after inoculation. Anti-fungal activity of extracts on H. Infestans decreased in the following order: G. kola at 0.12 g/ml (90.00%) > C. papaya at 0.25 g/ml (59.54%) > G. kola at 0.06 g/ml (59.15%) > G. kola at 0.03 g/ml (55.15%) > A. Indica at 0.06 g/ml (53.67%) > Z. officinale at 0.03 g/ml (52.65%) > control (7.71%). The seeds extracts of G. kola at 0.12 g/ml therefore proved more effective in the suppression of H. infestans relative to other botanicals and concentrations and were be recommended as a good alternative in its control in the field.   Key word: African eggplant anti-fungal, inhibition, protectants, toxicity.