Effect of substrate composition on production of volatile organic compounds from Trichoderma spp. inhibitory to wood decay fungi

The production of volatile organic compounds (VOCs) by two Trichoderma isolates grown on sand infused with either malt extract broth or a minimal medium with the carbon:nitrogen levels similar to that found in Scots pine wood was examined. The VOCs were trapped in tubes packed with chromatographic adsorbant, then analysed by Integrated Automated Thermal Desorption-GCMS. A total of 45 individual VOCs were recorded. Principle Component Analysis was used to establish that the production of individual VOCs was dependent on both the Trichoderma isolate and the growth media type. The inhibitory effect of the VOCs from the two Trichoderma isolates was also tested on four common wood decay fungi. Although VOCs from both Trichoderma species grown on a malt agar medium consistently inhibited the growth of all four target fungi, effects were negligible when the isolates were grown on a minimal agar medium. The importance of the production of individual VOCs on the inhibition of the wood decay fungi and the implications for the biological control of such fungi are discussed. (C) 1997 Elsevier Science Limited.