Phythonematoxic properties and nematicidal potential of Tithonia diversifolia extract and residue on Meloidogyne incognita infecting yam (Discoria rotundata)

Abstract

A laboratory study and a screen house experiment were conducted to determine the phythonematoxic properties and nematicidal potential of extract and residue of Tithonia diversifolia (Hemsl.) A. Gray on Meloidogyne incognita, (Kofoid and White) Chitwood infecting yam. Alkaloids and saponins were found to be present in the constituents of Tithonia ethanol extract. Also, Tithonia water extract significantly (P ≤ 0.05) inhibits M. incognita egg hatch by 98% from 2 days after incubation (DAI) and was more evidenced with 100% inhibition at 9 DAI in the in vitro studies. M. incognita (5000 eggs/plant) reproduction, number of eggs and juveniles and galling were significantly (P ≤ 0.05) suppressed by Tithonia residue treatment at a rate of 30 tons/ha on yam (Discoria rotundata) in the screen house. The extract and residue of T. diversifolia have potential for the control of root-knot nematodes.

Keywords:

• Discoria rotundata
• root-knot nematode
• Tithonia diversifolia
• synthetic nematicide
• bio-nematicide