| This study was conducted to develop an integrated disease management system of turfgrass using antagonistic microorganisms, fertilizers and fungicides as an alternative measure for the chemical control. Attempts were made to estimate the effect of calcium hydroxide, silicate fertilizer and urea on the mycelial growth of Rhizoctonia solani AG2-2 and the development of large patch in vitro and in vivo, and to establish the most promising combination of fertilizer, fungicide and antagonistic microbes. The reduction rates of agrochemicals in golf course using microbial products in Korea were decreased 29.3% to 80% yearly. The mycelial growth of Rhizoctonia solani AG2-2 were completely inhibited at 2,000, 1,000, and 3,000ppm concentration by calcium hydroxide, silicate fertilizer and urea, respectively. Inhibition effect of silicate fertilizer was the highest, but that of urea was the lowest compared with other treatments. Treatment of calcium hydroxide at rate of 100g/㎡ was the most effective, and control effect appeared from 30 days after treatment in spring, which was better in autumn than in spring. Silicate fertilizer treated at rate of 100g/㎡, 200g/㎡ in spring and 50g/㎡ in autumn were very effective. Urea at rate of 30g/㎡ was more effective than 60g/㎡ and 120g/㎡. The efficacies of mepronil and toclofos-methyl, applied twice in spring and once in autumn, were 83.8% in spring, which persisted to 70% in autumn compared with untreated plot. The efficacies of Trichoderma harzianum were the highest by 55% in spring, but those of Bacillus amyloliquefaciens BL-3 and Peudomonas putida were the highest by 80% in autumn among other antagonists tested, when two organisms were applied twice in spring and once in autumn. The most promising co-treatment against large patch was toclofos-methyl with Bacillus amyloliquefaciens BL-3 and calcium hydroxide at rate of 300g/㎡, silicate fertilizer 100g/㎡ and urea 80g/㎡. This combination treatment was more effective against autumn epidermics than spring epidermics and resulted in the efficacies of 93.1% suppression over the untreated plot as of October 21th. |
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