据笔者调查 ,海南省自 1999年入春以来 ,出现了干热天气 ,气温比常年偏高 3～ 5℃ ,丘陵、山地还常伴有大雾天气 ,日夜温差大 (2 0～ 35℃ )。致使一些地区果白粉病大面积流行 ,造成果大量落花落果和花而不实 ,开花多 ,着果少。因此 ,防治白粉病已成为果保花保果的当务之 According to the author’s survey, since the spring of 1999, Hainan Province has witnessed dry and hot weather, with temperatures 3 ~ 5 ℃ higher than normal. Hilly and mountainous areas are often accompanied by foggy weather with large temperature differences between day and night (20 ~ 35 ℃) . As a result, the prevalence of powdery mildew in some areas became widespread, resulting in a large number of poplar fruit falling and discoloring, with many flowers and few fruits. Therefore, the prevention and control of powdery mildew has become the fruit of the 保 保 Paul flower and fruit protection of the task