Nematicidal activity of phytochemicals and their potential use for the control of Meloidogyne javanica infected eggplant in the greenhouse

Abstract

Nematicidal activities of 17 phytochemicals belonging to the monoterpene, sesquiterpene, phenylpropene and alkaloid classes were assessed in vitro and in pot experiments under greenhouse conditions. The results showed that, based on LC50 values, monoterpenes and phenylpropenes were more toxic than sesquiterpenes and alkaloids to second-stage juveniles (J2) of Meloidogyne javanica. α-Terpinene (LC50 = 36.22 mg/L) displayed the highest toxicity against juveniles, followed by α-pinene (LC50 = 47.49 mg/L), nerolidol (LC50 = 53.60 mg/L) and eugenol (LC50 = 73.45 mg/L). Furthermore, α-pinene, α-terpinene and nerolidol were highly effective in reducing egg hatching of M. javanica after 7 days of treatment displaying IC50 values of 43.28, 49.26 and 50.39 mg/L, respectively. The three compounds showed nematicidal activity against eggs comparable to a reference nematicide, oxamyl. In pot experiment with eggplant, α-pinene, α-terpinene, eugenol and nerolidol induced remarkable reduction in number of galls, egg-masses and eggs per plant, and number of second stage juveniles in soil at concentration of 500 mg/L. Also, these compounds increased the growth parameters of eggplant compared with infected control. α-Terpinene gave nematode control and plant growth similar to oxamyl. The results suggest that these four compounds could be applied for M. javanica management.