Baseline information on using fermented crude extracts from <i>Cucumis africanus</i> fruit for suppression of <i>Meloidogyne incognita</i> and improving growth of tomato plants

Abstract

Bio-pesticides, when used as a post-planting pesticide, are limited by their potential ability to suppress the pest and their degree of phytotoxicity. Baseline information on the suitability of fermented crude extracts (FCE) of Cucumis africanus fruit as a post-planting bio-nematicide was determined on Meloidogyne incognita and growth of tomato in pot trials. Seedlings were inoculated with 1,130 eggs and juveniles/pot, while FCE  were applied weekly at 0, 10, 20, 30, 40, 50 and 60% dilutions. At harvest, nematode and plant data were  subjected to analysis of variance and the curve-fitting allelochemical response data (CARD) computer-based  model, respectively. Relative to inoculation level, final nematode population density (Pf) at the same level of  inoculation was reduced, while increasing dosages had no effect on Pf and reproductive factor values. Since  increasing dosages had no effect on Pf, the material could possibly still reduce this variable when applied below  10% dilutions. Dosages used were phytotoxic to tomato plants, but CARD model demonstrated that the material stimulated plant growth at dosages below 10%. In conclusion, baseline information from CARD  model suggested that FCE from C. africanus fruit have the potential to serve as a bio-nematicide and  bio-fertiliser on tomato provided the material was applied below 10% dilutions.

Key words: Cucumis africanus, bionemagation, effective microbe organisms, ground leaching technology, root-knot nematode.