Toxicity Tests with Vinegar Eelworm. I. Counting and Gulturing

The plant-parasitic nematodes have this in common with their relatives parasitic in animals, that they are unusually resistant to chemical control. It is not merely that substances lethal to the nematode are harmful to the animal or plant, for in both cases there are usually in the nematode’s life cycle free-living stages, and these are also highly resistant. Apparently the nematode cuticle, egg shell, and vitelline membrane are effective barriers to the penetration of many substances which might be expected to be good contact poisons. Several of the best modern insecticides have given disappointing results against plant eelworms (Ellis and Clayton, 1948). On the other hand some of the simpler halogenated hydrocarbons have been fairly effective, against both animal nematodes (CCl 4 , C 2 C1 4 ) and plant eelworms in the soil (C 2 H 4 Br 2 , C 3 H 4 Cl 2 ).