围垦区梨树金龟子的防治浙江省萧山市有２万多ｈｍ２（公顷）围垦土地，栽植了几十公顷梨树，近年来梨树上的金龟子为害十分严重，直接影响梨树的长势和收成。据１９９１年调查，金龟子在梨果上的为害率达１０％，在梨叶上的为害率为１２．５％。针对上述问题，于１９９２... Prevention and Control of Pear-tree Scarab in Reclamation Area There are over 20,000 hm2 (hectare) reclaimed land in Xiaoshan City, Zhejiang Province, where dozens of hectares of pear trees are planted. In recent years, the beetle damage on pears is very serious and directly affects the growth and harvest of pear trees. According to a survey conducted in 1991, the damage rate of chafer on pear fruit was 10% and that on pear leaf was 12.5%. For the above problem, in 1992 ...