严防梨火疫病传入我国梨火疫病为我国对外植物检疫对象，是仁果类果树的毁灭性病害。美国有１７个州发生此病，据美国农部１９７６年调查，全年因梨火疫病危害损失梨和苹果约４７０万吨。该病１９５７年传入西欧，１９５８年到１９６９年英国由于梨火疫病毁灭梨树约２万株... To prevent the introduction of pear fire blight in our country Pear Blight is the object of foreign plant quarantine in our country, is the pome fruit tree devastating disease. According to a survey conducted by the U.S. Department of Agriculture in 1976, about 4.7 million tons of pears and apples were lost to pear blight throughout the year. The disease was introduced into Western Europe in 1957, from 1958 to 1969, Britain destroyed about 20000 pear trees due to Pyrethrum blight ...