Research On Biological Control Of The Main Diseases Of Pear By Trichoderma

Pear scab and pear perennial canker are the two widely distributed pear fungus diseases caused by Venturia nashicola Tanaka et Yamamoto and Pnysalospora pinicola Nose in China, resulting in early fruit and leaf fall, thence yield and fruit quality loss. Traditional control of the two diseases involves a mass use of chemical products, raising the amount of residues on the fruit and environmental pollution, prone to building up resistance of the fungi. Accordingly, alternative measures are urgently called for to produce healthy pear fruits using as little and as environmentally-friendly plant protection products as possible.Trichoderma exists widely in the soil around root, on the leaf, and can destroy harmful fungi and counteract the selection of a resistant population, independent from degree and mechanism of resistance of the fungi, which make it a good candidate agent of biological control of fungi. Use of Trichoderma to control fungus disease has been reported to be successful in other plants than pear.In the present study, physiological responses of two fungi, Venturia nashicola and Pnysalospora pinicola Nose were investigated, when induced by Trichoderma. Results revealed that PPO, CAT, POD and SOD activities of both fungi decreased after infection by Trichoderma, along with reductions in GSH and ASA level and increases in MDA content and O₂^- generation rate. These indicated that Trichoderma damaged the active oxygen elimination system of fungi, leading to their membrane lipid peroxidation and growth inhibition.Furthermore, application of Trichoderma products to the control of the pear scab and pear perennial canker were tested, it was found that spraying of 4×10⁶ Trichoderma sporus suspension can efficiently control the occurrence of the two diseases to an economical end.