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Behavioural response of the entomopathogenic nematodes Steinernema carpocapsae and Heterorhabditis bacteriophora to oxamyl
Author(s) -
GAUGLER RANDY,
CAMPBELL JAMES F.
Publication year - 1991
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1991.tb04851.x
Subject(s) - oxamyl , heterorhabditis bacteriophora , biology , entomopathogenic nematode , carbamate , heterorhabditis , galleria mellonella , nematode , veterinary medicine , host (biology) , pesticide , toxicology , agronomy , ecology , medicine , biochemistry , virulence , gene
Summary Infective juveniles of the entomopathogenic nematode Steinernema carpocapsae show a low level of locomotory activity that is presumed to limit their usefulness as biological insecticides. A 30 μg ml ‐1 solution of the carbamate pesticide oxamyl reduced the proportion of nonmobile nematodes by nearly two thirds to 35%, while stimulating a 7.5‐fold increase in sinusoidal movement. This increase in activity did not result in a corresponding increase in host‐finding. Oxamyl treatment did not enhance infective juvenile pathogenicity to Galleria mellonella larvae. At higher concentrations, oxamyl caused aberrant nematode movement and partial paralysis. Heterorhabditis bacteriophora infective juveniles maintain a high level of locomotory activity. Treatment with 30 μg ml ‐1 oxamyl increased the proportion of sinusoidal over nonsinusoidal movements, but infective juvenile host‐finding and pathogenicity were significantly reduced. Higher rates impaired movement and induced complete paralysis. We conclude that oxamyl is incompatible with S. carpocapsae and H. bacteriophora. The concept of chemically activating infective juveniles to increased locomotory activity and thereby achieving enhanced efficacy is inconsistent with our results.