Abstract

A micro-feeding assay was developed for testing small amounts of synthetics and extracts as antifeedants for Hylobius pine weevils. We devised a simple setup consisting of 5 x 5-mm pieces of thin layer chromatography cellulose plates used in pairs for a bioassay involving choice. After application of 1.5 mul solutions and evaporation of the solvent, each plate received a 5 mul aliquot of 1 M sucrose as a feeding stimulant. The test period was 4 h at 25 degreesC with 6 days of starvation before the test, compared to just the 1 day sufficient for twig tests. Deprivation of water for 1 day at 65% RH before the test was critical because it increased feeding but not mortality. The combination of starvation and thirst reduced the relative variance ( coefficient of variation) to below 50%. There was a good correlation of antifeedant activity in the microassay with the activity in a standard twig test. The microassay needs only several mg for a test series, whereas the twig test needs grams

Published in

Journal of Pest Science
2004, volume: 77, number: 4, pages: 191-195
Publisher: SPRINGER HEIDELBERG

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