菜青虫(Pieris rapae Linne)是十字花科蔬菜主要害虫之一,近年来福州春季菜株平均被害率达85％,严重者达100％。笔者曾进行白僵菌防治试验,初步结果报导如下。 一、方法 喷菌前先进行田间虫情调查,选择菜青虫为害较严重的甘蓝菜作为试验地。然后采用培养一个半月的病菌,稀释戍1:50倍的菌液(每毫升含有854万个孢子),以手提式喷雾器喷射,至有液滴开始出现为止。以后每隔2天检查一次,并将死虫,死蛹拾回来,鉴定其死亡原因。凡是因白僵菌寄生致死,都有明显罹病症状,而在保湿条件下,培养2—3天即可长出白色菌丝和孢子。病菌致死率(％)=喷菌后罹病死虫总数/(活虫总数+各种死虫总数)×100对照区不作任何处理。 二、试验效果 在福建农学院及附近生产队进行了多次田间小面积防治试验,结果见表1。 由表1可以看出,应用白僵菌防治菜青虫其效果 Pieris rapae Linne is one of the major pests of cruciferous vegetables. In recent years, the average damage rate of spring vegetables in Fuzhou reached 85%, with severe cases reaching 100%. The author has conducted Beauveria control test, the preliminary results reported below. First, the method Spraying before the field insect investigation, choose cabbage caterpillar damage more serious cabbage as a test ground. The bacteria were then cultivated for a month and a half, diluted 1:50 times in bacterial liquid (8.54 million spores per ml), and sprayed with a hand-held sprayer until droplets began to appear. After every 2 days to check once, and dead insects, dead pupa pick up, identify the cause of death. All due to parasitic death of Beauveria bassiana, have obvious symptoms of illness, and in moist conditions, 2-3 days to grow white mycelium and spores. Bacterial lethality (%) = total number of dead bugs after spraying / total number of live bugs + total number of dead bugs × 100 Control area without any treatment. Second, the test results Fujian Agricultural College and the nearby production team conducted many field small area control test, the results shown in Table 1. As can be seen from Table 1, the application of Beauveria bassiana control cabbage worm effect