The Detection and Control of Strawberry Anthracnose
Date Issued
2015
Date
2015
Author(s)
Liang, Yu-Ping
Abstract
Anthracnose (Colletotrichum) is a severe disease of strawberry (Fragaria × ananassa Duchessne) in Taiwan, which often results in wilting of plants. The capability of detecting and monitoring the inoculum sources and density in the field would aid in prevention and control of this disease. Thus, this research is aimed to develope a semi-selective medium for pathogens of strawberry anthracnose, and to apply it to detect Colletotrichum in strawberry plants, soil and other plants. By comparing the inhibition effects of 25 antimicrobial chemicals on Colletotrichum and major contaminating microbes, and selecting those inhibiting the latter but not the former, it was found that PDA-BBITM (potato dextrose agar (PDA) with 5 mg/L benomyl, 10 mg/L boscalid, 5 mg/L iprodione, 50 mg/L tetracycline hydrochloride, and 10 mg/L metalaxyl) could effectively isolate Colletotrichum from strawberry plants and weeds with less disturbance from the contaminating microbes compared with previously used semi-selective media. Besides, this medium could also detect Colletotrichum from crowns of symptomless strawberry seedlings. Applying this medium to detect Colletotrichum in field-grown seedlings, it showed that the detection rate is positively associated with the replanting rate. Thus, it is suggested that PDA-BBITM can be applied in the system of healthy seedlings certification. For detecting Colletotrichum in soil, the same combination of antimicrobial chemicals could also be used, but the PDA medium needed to be replaced with Czapek-Dox agar, modified by using pectin as the carbon source, to reduce the disturbance of contaminating microbes. By this modified Czapek-Dox agar, it was discovered that the survival rate of Colletotrichum conidia in soil would be less than 30% after 60 days, while solarization and flooding could reduce the survival rate rapidly. In addition, diseased debris could hardly be detected with Colletotrichum after buried in soil for 70 days, indicating that Colletotrichum might not be likely to survive in soil for a long time in wet and hot climate in Taiwan. None of 11 tested weeds developed anthracnose symptoms after inoculated with Colletotrichum conidia, but most of them could be detected with Colletotrichum at 28 days after inoculation. We also found that the weeds collected from strawberry growing fields, including Clinopodium gracile (Benth.) Kuntze and Eleusine indica (L.) Gaertn., could be detected with Colletotrichum pathogenic to strawberries. Finally, to compare and evaluate the control effeciency of fungicides and antagonistic microoragnisms to strawberry anthracnose, difenoconazole, thiabendazole + oxine-copper, pyraclostrobin, penconazole, triflumizole, Streptomyces sp. Yu-01 and Bacillus subtilis were tested in pot tests, and the results showed that pyraclostrobin exhibited the highest control rate among them.
Subjects
Colletotrichum
control
detection
semi-selective medium
strawberry
survival
SDGs
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-104-R01645017-1.pdf
Size
23.54 KB
Format
Adobe PDF
Checksum
(MD5):9078acf05f9a3bb0a74e36439f0cb8e4