THE POTENTIAL OF SEPARATE AND COMBINED APPLICATION OF SOME PLANT EXTRACTS AND DEFENSE INDUCER MOLECULES FOR CONTROL OF Meloidogyne javanica

Abstract

The effect of aqueous extracts of Nigella sativa, Ferula assa-foetidae, Peganum harmala, and Portulaca oleracea, separately and in combination with salicylic acid (SA), β–aminobutyric acid (BABA), and jasmonic acid (JA) were examined for the control of M. javanicain the laboratory and greenhouse. Eggs and second-stage juveniles were exposed to different concentrations of the plant extracts and defense inducer (DI) molecules. In the greenhouse, the effect of treatments on the number of juveniles in roots, nematode reproduction, and plant growth were evaluated. The highest mortality of juveniles and lowest egg hatch occurred after exposure simultaneously to F. assa-foetidaextract and BABA for 72 hr. Concomitant application of F. assa-foetidaextract with 1.5 mM concentration of all DI molecules inhibited penetration of juveniles into roots as effectively as cadusafos which was used as a standard nematicide. Concurrent application of 1.5 mM BABA or SA with all of the plant extracts lowered nematode reproduction similar to the nematicide standard. Application of plant extracts and DI molecules did not affect fresh or dry shoot weight, but did affect shoot height and root fresh weight. Based on our data, the defence inducer molecules, in combination with all of the plant extracts that were tested, have potential for the control of M. javanica.