Potential of Trichoderma spp. isolates and Trichoderma bioactive metabolites for biological control of aphid pests of cereals.

In this study we report the effects of some long-chain alcohols, obtained from an isolate of the fungus Trichoderma citrinoviride, on feeding preference of the aphid Rhopalosiphum padi, a major pest of cereal crops. Purification of these fungal metabolites was carried out by a combination of direct and reverse phase column chromatography and thin-layer chromatography. Chemical identification, performed by spectroscopic and chemical methods including nuclear magnetic resonance and mass spectrometry, led to isolation and structure determination of different primary alcohols of the general formula R-OH, wherein R is a long, unbranched, unsubstituted, linear aliphatic group. Feeding preference tests carried out with winged and wingless morphs of R. padi showed that these metabolites had a distinctly high fagodeterrent activity and thus restrained aphids from settling on treated leaves. The tested metabolites, have no chiral centers and therefore can be obtained in good yields through chemical synthesis, besides natural sources and can be potentially utilized for novel applications in biotechnical control of aphid pests.