TOXICITY OF HARMAL, RHAZYA STRICTA, TO MELOIDOGYNE INCOGNITA AND PRATYLENCHUS JORDANENSIS

Abstract

Aqueous extracts of leaf, root and rhizosphere soil of harmal, Rhazya stricta, were tested against Meloidogyne incognita and Pratylenchus jordanensis under controlled conditions. Leaf extract exhibited ovistatic effect at 12.5 and 25 per cent and ovicidal effect at 50-100 per cent concentration against M. incognita. Sixty-two per cent reduction in eggs hatch was recorded at 100% concentration of leaf extract. Leaf and root extracts exhibited higher rate of toxicity against second-stage juveniles of M. incognita and all stages of P. jordanensis than soil extract. The rate of nematode mortality increased markedly with increase in concentration of leaf and root extracts from 50-100 per cent. Application of chopped leaves of harmal at 2.75 T/ha to an alfalfa field reduced the populations of P. jordanensis in soil and roots.