Diagnosis, Identification And Biological Control Of Blueberry Disease

The planting of blueberry in China has been industrialized on a massive scale since it was introduced from abroad.However,during this process,blueberry related diseases also occurred.So far,two major types of diseases have been discovered,infective disease and physiological disease.Among all kinds of infective disease,the leaf spot infected by fungi pathogen has the earliest onset and widest spread,while nutritional deficiency symptoms of soil is the most common one of physiological disease.The research is about new blueberry leaf spot disease in Dalian,Liaoning province of China.Separated and purificated one strain fungi from lesions of leaf and Koch's postulates were fulfilled.With morphological observation,ITS andβ-tubulin sequences' identification, we got a result as the blueberry leaf spot disease' pathogen was Pestalotiopsis clavispora in Liaoning Province.This establishes a method to identify fungi pathogen.Then endophytic fungus which were isolated from the Blueberry were chosen preliminarily.Through ITS sequences' identification,they were Trichoderma hamatum and Chaetomium globosum.The control rate of zymotic fluid of 10%,20%,30%by T.hamatum were 52.69%,67.31%, 78.31%and the same to C.globosum number were 69.19%,74.47%,83.36%.Inhibiting rates of T.hamatum and C.globosum against P.clavispora by method of flat paired culture also proved to be effective.Furthermore,we tested that T.hamatum can produce antifungal chitinase and investigated physiology characters both of them.This work could provide a potential method of biological control against P.clavispora.Blueberry is planted within nutrient fluid which has vermiculite and six different levels of Magnesian Ion concentration between 0.2 mmol/L and 10 mmol/L.Two months later,we discovered that the plant grew appropriately in the nutrient fluid with the level of 12.5mmol/L, and high level results to curled exsciccation of leaves while low level leads to chlorosis.By testing the growth of plants,photosynthetic parameter,chloroplast pigment and conductivity,we reached the conclusion that ground substance of 1.5 mmol/L magnesium concentration is best for the growth of blueberry and the mass concentration should be between 0.095%to 0.11%.This experiment laid the foundation of Magnesian nutrition diagnosis and rational application of Magnesian fertilizer.