[The toxicity of acaricides and synthetic pyrethroids against red spider mite, Tetranychus urticae Koch Complex]
1992
Yusof Ibrahim | Dzolkhifli Omar | Adnan Othman (Pertanian Malaysia Univ., Serdang, Selangor (Malaysia). Plant Protection Dept.)
The toxicity of four acaricides and five synthetic pyrethroids against red spider mite, ((Tetranychus urticae Koch)) complex, was evaluated in the laboratory using the slide-dip technique. Mortality was recorded at 48 h post treatment and data were subjected to probit analysis. Based on the LC* values, the order of toxicity of the chemicals tested was as follows: amitraz deltamethrin = cypermethrin (Cymbush) = fenvalerate cypermethrin (Ripcord) permethrin bromopropylate = chinomethionate azocyclotin. The LC* value for amitraz was 2.5 ppm while for chinomethionate it was 37.5 ppm. Repeated tests on the toxicity of the pyrethroids using leaf-dip technique at the LC* and LC* values obtained earlier from the slide-dip technique revealed a lower level of mortality. The highest mortality obtained was 21.0 percent from fenvalerate treatment at the LC* value. Thus test techniques were found to give different toxicity values on the red spider mite.
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