BIOSENSOR FOR VOLATILES RELEASED BY DAMAGED PLANTS

One of the most crucial problems in biological or biotechnical plant p rotection is the timing of starting an application. The proposed biose nsor measuring overall degree of plant damage is a useful tool for sol ving the problem. If plants are damaged, for instance by cuts made art ificially or by biting or chewing insects, volatile organic compounds (VOCs) will be released to a higher extent and in a different composit ion compared with undamaged plants. The biosensor based on an electroa ntennographic technique uses the sensitivity and selectivity of an ins ect's antenna to detect the changes in composition of the VOC. This me thod is comparatively simple, inexpensive and sensitive (e.g. 1 ppbv c is-3-hexen-1-ol, dynamic range: 1 ppbv-100 ppmv) with respect to usual mass-spectrometric methods of VOC trace analysis. Moreover, the respo nse time (10 ms) and the measurement cycle time (3 min) are short and the biosensor yields an overall parameter easier to deal with than com plex mass-spectrometric data arrays. The lifetime of one antennal prep aration, however, is 4 h and has to be improved. This paper presents r esults emerging from laboratory experiments with the Colorado potato b eetle (Leptinotarsa decemlineata Say).