Compatibility of Steinernema Feltiae with Nemarioc AL Phytonematicide

Abstract

Background: Following the withdrawal of methyl bromide from the agrochemical markets, Steinernema feltiae was introduced into the South African agro-ecosystems as a biocontrol agent for various soil-borne pests including plant-parasitic nematodes. During the same time, Nemarioc-AL phytonematicide was being developed as an alternative to methyl bromide. The aim of this study was to assess in vitro the compatibility of S. feltiae and Nemarioc-AL phytonematicide. Materials and methods: Approximately 50 infective juveniles (IJ) of S. feltiae were exposed to 0.0, 1.5, 3.0, 4.5, 6.0, 7.5 and 9.0% Nemarioc-AL phytonematicide. The survival and mortality were recorded after 24, 48 and 72 hours (h). Results: At 24 h, the phytonematicide did not affect IJ. However, at 48 or 72 h, IJ survival and corrected mortality counts were inversely and directly proportional to increasing concentrations of Nemarioc-AL phytonematicide, respectively. Infective juvenile corrected mortalities at 0-15% and 0-19% were observed at 48 and 72-h, respectively. Survival and corrected mortality curves did not intercept each other in both trials, suggesting that IJ were tolerant to the phytonematicide. The optimum Nemarioc-AL phytonematicide concentrations affecting survival of S. feltiae IJ were 9 and 41% at 48 and 72 h, respectively. Conclusion: Since Nemarioc-AL phytonematicide caused mortalities of less than 20-30% for up to 9% phytonematicide, according to the International Organization for Biological and Integrated Control of Noxious Animals and Plant (IOBC) laboratory trial ratings, the results suggested that Nemarioc-AL phytonematicide and S. feltiae were compatible. Therefore, the phytonematicide and S. feltiae could be used concurrently in various agricultural systems.