Reaction of meloidogyne incognita eggs to hatching in aqueous plant extracts

The southern root-knot nematode, Meloidogyne incognita is a major limiting biotic factor affecting plant growth and yield in the tropical and sub-tropical worlds. Synthetic pesticides constitute the principal means to control the menace of the pest. Natural pesticides derived from plant parts offer alternative control strategy due to the identification of nematicidal properties in many flowering plants. A preliminary in vitro experiment evaluated the potential of five plant extracts (pawpaw root, leaf, seed and false yam tuber and leaf) to inhibit the hatching of eggs of M. incognita. Three concentration levels (w/v) that is 2, 4, and 8% of cold aqueous extracts of the plant parts were filtered into 6 cm Petri dishes and Petri dish, infested with 100 M. incognita eggs. Hatching of eggs was monitored over a three time period; 24, 48 and 72 h after infestation of the eggs in the respective aqueous extracts. The best result was obtained with false yam tuber extract in which 0, 3 and 5 eggs hatched while 26, 44 and 76 eggs hatched in distilled water (the control treatment) representing a hatching inhibition of 100, 93 and 93% at the three exposure time and concentration levels respectively. The current study which documents the first attempt at using false yam, Icacina senegalensis to control plant parasitic nematodes is environmentally friendly and cost effective. The formulation of the active ingredients of these botanicals as bio-pesticides would reduce the over-dependence on synthetic pesticides which have deleterious effects on man and the environment.