頁籤選單縮合
題名 | 甘蔗露菌病之研究=Studies on the Downy Mildew Disease (Sclerospora sacchari Miyake) of Sugarcane |
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作者 | 王卓三; 王茂軒; | 書刊名 | 中華農學會報 |
卷期 | 22 民47.06 |
頁次 | 頁51-62 |
關鍵詞 | 甘蔗露菌病; |
語文 | 中文(Chinese) |
英文摘要 | About forty-five years ago, a new disease of sugar cane was first found in Tainan,Taiwan. The symptom of the disease was yellow stripe on the leaves, and stunting in the young stage of plants. Sugar content of diseased plant was decreased 45%. MIYAKE indicated that the cause of the disease was Sclerospora sacchari MIY., and named the disease as downy mildew. In 1909 to 1911, it was prevalent in the south part of the island, however, during the past forty years it was limited at some localities. Recently, this disease spread all over the island except eastern Taiwan, and being a most important disease now. Three methods of spread of the disease have reported by the others: 1. conidia of cause transimissed to healthy one by one, 2. Oospores of the cause in the soil infected year by year and 3. Diseased stalk cutting off as seed-cane transprot to another district. The last one may be the most important factor because this disease spread so quickly in a short time. According to Mr.J.P. MARTIN report, downy mildew disease was found in Australia,Fiji, India, Japan, New Gurinea, Philippines and Siam, but it was not a major disease except Taiwan (Formosa), therefore, no further studies of this disease have reported. The following results were the studies of this disease by the author in 1954 to 1956. 1. Results of tests in laboratory and field observation, we found that, there were relationship between conidia production of caused organism and temperature, air-moisture and rainfall. Conidia production inhibeted in dry condition, lower temperature and rain. It is no relation between conidia production and soil moisture. May to October was the spread period of this disease every year in Tsungyeh or Hsinchu district. (See figures 1,2.) 2. Many workers reported that, oospore of causal organism was the infected material in the soil. In the test of diseased stem and leaves, we have a nagitive result.The author assumed that soil infection was not importance of this disease. 3. Mr.CHU has reported that a hot water treatment on the diseased cane cuttings at 40℃ to 46℃ for one hour and then 52° for 20 minutes continually could control the disease, however, some workers repeated it several times just got nagitive results. The author stated that two methods of hot water treatment for control diseased cuttings of downy mildew: (a) diseased single-eye or two-eye sutting was treated in 45℃ water for one hour and drying about 24 hours in room temperature condition then treated it again at 52℃ for 60 minutes; (b) cuttings was treated by hot water at first period as (a), but the second treatment was in 55℃ water for half an hour. Those two different treatments were repeated 13 and 10 times during the last two years respectively. (See table 3.) According to the author opinion the former was better than the later. The germination and growth rate of sugar cane which was treated by hot water better than the control. (See table 4.) 4. In the field test, we found that 0.2% karathane and 4-4-50 type of Bordeaux mixture spraying interval two weeks can protect the healthy plant free from the disease. 0.2% Phygon interval one week had been gotten the same result. It is apparent that the residual protective action of karathane and Bordeaux mixture last on sprayed leaves for 14 days, but it may be more saftly that apraying interval 10 days. (See table 5.) 5. Sugar content of diseased plant decreased differently either varieties or infective times. The earlier infected plant decreased more sugar than the later. Diseased plant which developed from diseased cuttings lost 50% to 60% of sugar than the healthy plant while the healthy plant which sprouted from diseased cutting was lower 20% of brix of cane juice than the healthy plant which germinated from healthy cutting.(See tables 1,2.) |
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