Effects of Methanolic Extracts from the Leaves of Brimstone, Cassia, Lemon Grass and Chanca Piedra on Meloidogyne Incognita in the Laboratory

Abstract

A laboratory experiment was carried out at the Nematology Unit of International Institute for Topical Agriculture (IITA), Ibadan in 2005. The experiment was conducted to assess the effect of 0,5,10 and 20% methanolic extracts of brimstone (Morinda lucida), Cassia (Cassia acutifolia), Lemongrass (Cymbopogon citratus) and Chanca piedra (Phyllanthus amarus) as well as the effect of 1000 ppm carbofuran on the egg hatch and juvenile mortality of Meloidogyne incognita. The experimental design was a factorial type fitted into a completely randomized design (CRD). Laboratory tests were also carried out using standard procedures to determine the bioactive materials with nematicidal or nematostatic properties in the test plants. The results show that on the 8th day of observation, carbofuran and the highest level (20%) of aqueous extracts of all test plants completely inhibited egg hatch while the control (distilled water only) recorded 93% commulative egg hatch. It was also observed that between 98-100% juvenile mortality was recorded in all treatments by the 8th day whereas the untreated control had about 8% juvenile mortality. Generally, treatment level and length of exposure time to treatment were proportional to increased juvenile mortality. Tannins and flavonoids were present in all the test plants while saponins and oxalates were found in all the test plants except in Cassia acutifolia and Cymbopogon citratus respectively. Crude alkaloids were present only in C. acutifolia