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一、前言在美国东南部,桃树夭折病(PTSL)是桃树生产中的一个极其严重的问题。该地有900多万株桃树,年产35万吨,约占美国鲜桃总产量的一半。PTSL 引起的桃树死亡情况每年不一。近几年,每年死树约3%(即30万株),相当于每年损失200万美元。树休严重死亡发生在1982年(仅佐治亚州30万株)、1978年(东南地区50万株)和1984年(东南地区50万株)。
I. INTRODUCTION In the southeastern United States, PTSL is an extremely serious problem in peach production. There are more than 9 million peach trees in the area, with an annual output of 350,000 tons, accounting for about half of the total U.S. peach production. Peach tree deaths caused by PTSL vary from year to year. In recent years, about 3% of tree dead (or 300,000 trees) each year is equivalent to an annual loss of 2 million U.S. dollars. The serious death of trees occurred in 1982 (only 300,000 in Georgia), 1978 (500,000 in the southeast) and 1984 (500,000 in the southeast).