Inhibition of Esterase Mediated Hydrolysis of 1-Naphthyl Butyrate in the B-Biotype Bemesia tabaci (Hemiptera; Aleyroididae) in Australia
Mar 8, 2019

Crop Protection WCRC WCRC2

A colourimetric squash test was used to distinguish between native and B-biotype Bemisia tabaci (Gennadius), for field identification in Australia. This test is based on overproduction of esterase iso-enzymes by B-biotype B. tabaci. This test has occasionally been shown to give a false negative due to organophosphates temporarily binding to esterase enzymes and inhibiting its reaction with an artificial substrate 1-naphthyl butyrate (Byrne and Devonshire, 1991). While it is desirable to have a quick whitefly identification test, it is also important to know if prior treatment with organophosphates will affect the results. Results obtained by polyacrylamide gel electrophoresis demonstrated that the esterase mediated hydrolysis of the artificial substrate 1-naphthyl butyrate is inhibited from 24 to 48 hours after exposure of B-biotype B. tabaci to 0.1% active ingredient organophosphate concentration on exposed leaves. This hinders the ability of the quick identification test to distinguish between resistant B-biotypes and susceptible native B. tabaci if organophosphates were used within 48 hours.

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