| Chinese wolfberry is a kind of Solanaceae Lycium shrub, its fruit is precious Chinese herbal medicines and health products. In recent years, the areas of wolfberry in Gansu province continues to expand, and wolfberry anthracnose has become one of the most serious diseases of wolfberry fruit, once it occurred, will cause devastating damage and great economic losses. In view of the importance of the disease, in this paper, based on the pathogen identification, we studied the biological characteristics of pathogen fungi, the epidemiology of disease in field, to determine toxicity of fungicides, in order to provide a theoretical basis for deeply understand the disease, to make scientific field management and comprehensive prevention and control measures. The main results as follows:1.The fruits of Chinese wolfberry with typical anthracnose symptoms were collected from Jingyuan County and Jing Tai County. By using the method of tissue isolation, we get the fungi which caused Chinese wolfberry anthracnose. By means of conidial suspension and the mycelium in two ways to inocubate to the wolfberry fruit by acupuncture treatment, the strain reisolated from the diseased fruit was the same as the pathogen we used. This showed that the isolated pathogens were pathogenic fungi of Chinese wolfberry anthracnzzose. The 4 isolates were transferred onto PDA plates and observed it. The first mycelia were colorless, and turned grey after 5 days. The conidia were clavate, single cell, colorless, one or more oil drops, 9.41-16.55×2.94-6.67μm; the acervulus not have bristles and nearly circular; conidia heap were orange red. Through the analysis of ITS sequence, the 4 isolates were highly homologous to Glomerella acutata, the similarity was 100%. By using neighbor-joining method, the phylogenetic tree of Colletotrichum species was constructed, JAX had the nearest distance with FJ938293.1(Glomerella acutata) in Ge Bank, the nearest of DSX, WHX and JTX were FJ478063.1(Glomerella acutata). According to the morphological and molecular identification results, the 4 tested pathogens were identified as Colletotrichum acutatum.2. In this study, biological characteristics of Colletotrichum acutatum was studied by mycelia growth method and spore germination method. The results showed that: the optimum temperature for mycelia growth was 25℃; 10% wolfberry juice of PDA was the best of the 8 culture media in the experiment; the optimum p H was 6; the optimum carbon source was glucose and mannose; the optimum nitrogen source was Gly, 25℃, p H6, light condition, sucrose and Na NO3 were the best for sporulation. The rate of spore germination was highest under the condition of temperature, 30℃, p H5 and RH:100%. The mycelium and conidium could not survive at 50℃ for 10 min and 55℃ for 10 min respectively.3. In 2013 and 2014 years, the results of the observation of Chinese wolfberry anthracnose occurrence showed that: Chinese wolfberry Anthracnose in the form of conidia and mycelium overwinter in the stiff fruits, which become the next primary infection source. In 2013 and 2014, the disease was beginning at mid June. In 2013, the incidence continues to rise at mid June to mid September, in the middle of September reached 60%, the disease was epidemiced, the farmers suffered heavy losses. In mid July 2014 the incidence rate was 2.49%, after mid July the incidence rate remained at this level, Chinese wolfberry anthracnose not really popular.4. The sensitivity of the colony growth of Colletotrichum acutatum to 19 fungicides was tested by inhibition zone method. The inhibition of spore germination by each fungicide were determined by sporulation method. A total of 10 kinds of fungicides used for the field trials. The results showed that the control and prevent efficacy of 430 g·L-1 tebuconazole SC(3000×), 60%triazole ether-metiram WG(2000×), 450g·L-1 prochloraz EW(1200×) and 40%flusilazole EC(6000×) against C. acutatum were more than 70%. |
PDF Full Text Request