Biological Control of Phytophthora Blight on Sweet Pepper

• Main Authors: Chen, Chien-Ming, 陳建名
• Other Authors: Wu, Wen-Shi
• Format: Others
• Language: zh-TW
• Published: 1996
• Online Access: http://ndltd.ncl.edu.tw/handle/69054509141691910312

碩士 === 國立臺灣大學 === 植物病蟲害學系 === 84 === A total of 5220 bacteria isolated from rhizosphere of tomato and sweet pepper were screened by dual cultures. Concomitant cultures on 5 kinds of media for ability to control Phytophthora blight of sweet pepper caused by Phytophthora capsici. Seven isolates exhibited antagonism not only to P. capsici but also to other plant pathogenic fungi and were brought to bioassy in the screenhouse. Isolate #294 among seven isolates was more consistency in their control efficacy and reduced the amount of propagule survived in the potting media of P. capsici. The combination of#294 antagonist and various ingredients which were molasses, glutamate, calcium hydroide, peptone, and ammonium oxalate to constitute C5 and A10 formulation. The maintenance of #294 antagonist in C5 and A10 formulation lasted for 3 months with population density of 10 cfu/ml. While the population with N.B. declined rapidly in 7 days. Compare the populationmaintenance of C5, N.B., and 0.1M magnesium sulfate solution on #294 antagonist survival. The results showed that the hightest recovery freguencies of #294 antagonist labelled with antibiotic resistance markers were potting medium incorporated with C5 formulation. The amount wuth C5 was 5.9 times higher than N.B. in 7 days. By means of adding detergent diluted to 1000ppm,the modified formulation was effective to inhibit the sporangia germination of P. capsici than C5. A10 and other liquid fertilizers tested which included fish extract, sea algae extract, humic acid, Garmu, Condola, complex of amino acids and complicated liquid fertil- izers. In greenhouse experiment, modified formulation reduced the disease index in average by 50% and better than previously formulations, even though with antagonists involved in them.