At field rates (ca 0·1–10 μg active ingredient/ml), non-fumigant nematicides such as oxamyl do not kill plant-parasitic nematodes directly but act by impairing neuromuscular activity. The present study has shown that neutral lipid levels in 2nd-stage (infective) juveniles of Globodera rostochiensis, which had been incubated with the oximecarbamate nematicide oxamyl (1 μg a.i./ml) for between 8 and 35 days, were significantly (P < 0·05) greater when compared with controls maintained in water alone. The difference between treatments was found to be due principally to changes in the lipid content in the posterior half of the body which appears to act as the major long-term lipid store. When nematodes were allowed to recover for 72 h following incubation for 35 days with oxamyl, their infectivity was not significantly (P > 0·05) different from that of controls. This work is discussed in relation to the action of oxamyl and similar nematicides and to the use of controlled-release formulations as a means of increasing their efficacy.
