Effects of aldicarb on the behavior of Heterodera schachtii and Meloidogyne javanica.

The toxic effects of sublethal concentrations of aldicarb were studied on eggs and second-stage larvae and males of Heterodera schachtii and second-stage larvae only of Meloidogyne javanica in a quartz sand substrate. Aldicarb was more toxic to eggs of H. schachtii than to those of M. javanica. Complete suppression of hatching occurred between 0.48 and 4.8 microg/ml aldicarb for H. schachtii whereas 100% inhibition of hatch of M. javanica occurred between 4.8 and 48.0 microg/ml. M. javanica hatch was stimulated at 0.48 microg/ml aldicarb. Migration of second-stage larvae of H. schachtii and M. javanica in sand columns was inhibited under continuous exposure to 1 microg/ml aldicarb. Infection of sugarbeet and tomato seedlings by larvae was inhibited at 1 microg/ml. H. schachtii males failed to migrate toward nubile females at 0.01 microg/ml aldicarb. This was partially confirmed in a field study in which adding aldicarb to soil resulted in fewer females being fertilized.