Poplar Stain Fungus And Their Biological Control

Poplar is one of China's four major tree species, but also China's fast growing tree species, but during the processing and useing would be a serious discoloration of the wood, reducing the timber level and the quality of end products, a direct impact on the economic benefits of production. Therefore,biological control of poplar sapstain fungi is studied to be the very real economic significance.Firstly,studied the sapstain fungus,then selected the strain B19 with broad antagonistic effect to staing fungus and studied the antagonistic mechanism of B19 under fermentation conditions.The results are as follows:1. Stain pathogen Lasiodiplodia theobromae (Pat.) Griff.& Maubl. cause poplar stain speedly,but Curvularia lunata relatively slow.The influence of environmental factors on the staining fungus showed that both two fungus are sensitive to the extremely acidic conditions,especially C. lunata growed better under alkaline conditions than slightly acidic conditions.They were capable of growing in the temperature range of 10℃to 35℃. Their maximum, minimum inhibition temperature were 40℃and 5℃. Fungus can grow best under full illumination conditions.2.A strain B19 had stronger and stable antagonistic effect against staining fungus were selected from eight bacteria through agar plate experiment.3.The wood chips that dealed with B19 fermentation filtrate still healthy ten days after placing in the dish which filled with staining fungus.However the control chips occur with varying degrees of staining a week after.This showed that B19 can effectively prevent the wood discoloration.4. The fermented conditions of strain B19 were optimized.When the strain cultured with conditions as follow:culture medium temperature 35℃and culture time 46 hours,initial pH 6.0,200r/min in shake,revolutions with 50ml medium in 250ml conical flask,the strongest antagonistic effect would be exhibited.5. Strain B19 can inhibit mycelim growth and germination of staining fungus spores.After treated by B19 fermentation filtrate mycelial deformation, spores do not germinate,swollen and form a round spherical bubble.