JOURNAL OF PLANT PROTECTION RESEARCH Vol. 48, No. 2 (2008)

INTERACTION OF ROOT-KNOT NEMATODE (MELOIDOGYNE JAVANICA) AND TOMATO AS AFFECTED BY HYDROGEN PEROXIDE

Muwaffaq Ramadan Karajeh*

Department of Plant Protection and IPM, Faculty of Agriculture, Mutah University

Karak P.O. Box 7 (zip code 61710), Jordan

Abstract:

The effect of hydrogen peroxide (H₂O₂) on root-knot nematode (RKN, Meloidogyne javanica) in tomato was investigated. Soil drenching with exogenous H₂O₂ was done using seven H₂O₂ concentrations (1, 10, 100, 250, 500, 750 and 1 000 mM) at different application times (24 hours before the time of plant inoculation with the RKN (T1), at the time of inoculation (T2), and 24 hours after the inoculation time (T3). The nematode reproduction rate (eggs/g fresh root) was significantly reduced in all H₂O₂ treatments compared with the untreated control. The lowest reduction in nematode reproduction occurred at 10 mM H₂O₂. The application times T1 and T2 were significantly higher in reducing the reproduction rate than T3 at 250, 750 and 1 000 mM H₂O₂. The content of endogenous H₂O₂ in the treated plants was significantly higher than in the non-treated plants. Some phytotoxicity was apparent at the higher concentrations of H₂O₂ (≥ 500 mM) in the treated plants due to the accumulation of the endogenous H₂O₂. The treatments with 1 and 10 mM H₂O₂ did not differ from the untreated control in plant chlorophyll content while the content was significantly reduced at the higher concentrations. Exogenous application of H₂O₂ may have a direct effect on the nematode reproduction and an indirect effect on the treated tomato plants that can be elicited by H₂O₂ to resist the nematode infection.