Study On Physiological And Ecological Characteristics Of Naval Orange Anthracnose Pathogens And Disease Control

Jiangxi Ganzhou is one of the main producing areas of naval orange. In recent years, with the continuous expansion of cultivation, complex and changing climate, lead to more large-scale anthrax orange orchard, seriously affected the yield and quality of navel orange. So, naval orange anthrax-specific research was necessary and urgent.In this paper, six strains of naval orange anthracnose pathogens were isolated from diseased leaves. According to different collecting zone, named respectively: AYB4,XFB8-1,LNB21-2,HJA9,GXA5-1,LNB11。According to the experiment results of cultural and morphological characteristics, consulted the classification criteria of Colletotrichum edited by Sutton (1980). The strain GXA5-1 and LNB21-2 biological characteristics, the strain GXA5-1 chemical drug indoor and biological control bacteria affect test.The results were as follows:1 six strains of naval orange anthracnose pathogens colony and morphology characteristics1.1 Colonies characteristics28℃, PDA, six days, myceliums were white or yellowish white or gray. Edges were neat. Myceliums were sparse or dense. The Colonie backs secreted orange or purple or dark green pigment. Sometimes, we could clearly visibled concentric physalospora.1.2 Morphology characteristics28℃, PDA, six days, AYB4,XFB8-1,LNB21-2 conidia were cylindrical, HJA9,GXA5-1 LNB11 conidia were crescent. The sizes of conidia were 11.74-22.41×2.86-6.29μm.Fungi sexual stage was not observed, trauma to germs invading.2 The strain GXA5-1 and LNB21-2 Biological characteristics2.1 Mycelia optimum temperature was 28℃. 2.2 The percentage of conidia germination was 100% at relative humidity range above 75%.2.3 Mycelia and conidia could growth in Various pH, the best pH was 6, but Neutral partial acidic can growth well.2.4 The growth of mycelia and conidia were not strict with light conditions.2.5 The best carbon source was glucose.2.6 The best nitrogen source was KNO3.2.7 The results of Physiological and biochemical appraisal, could secreted various extracellular enzyme such as catalase,oxidase,amylase,Lacquer enzyme etc, could use gelatin and Various sugar, but could not produce H2S.3 The strain GXA5-1 Chemical drug indoor testChemical drug indoor test indicated that Prochloraz (25%) Could restrain mycelia growth and inhibition conidia germination, EC50 of inhibit growth conidia was 0.021 mg/mL, EC5o of inhibition conidia germination was 0.004 mg/mL.4 The strain GXA5-1 Biological control bacteria effect testThe result of Biological control bacteria effect test, Streptomyces albogriseolus, inhibit mycelia growth was the best, diluted 10 times,100 times,200 times the relative inhibition rates were 96.31%,85.82%,62.69%. Bacillus subtilis Cohn inhibit conidia germination was the best, diluted 10 times,100 times,200 times the relative inhibition rates were 89.93%,67.59%,48.76%.