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农业有史以来,病虫灾害是越来越多了,还是越来越少了?关于世界范围发生病虫害所造成的损失率,国外1967年和1994年分别有两个数字,即34.9%和42.1%,显然损失率是增加
Pest and disease have been increasing or decreasing in agriculture ever since? With regard to the losses caused by pests and diseases worldwide, there are two figures for foreign countries in 1967 and 1994 respectively, 34.9% and 42.1% , Obviously the loss rate is increased