国产25％灭幼脲Ⅲ号胶悬剂在供试浓度范围内(0.25—250ppm)对菜粉蝶(Pierisrapae L.)有较强的生物活性。可抑制卵的孵化并引起初孵幼虫死亡,幼虫龄期愈小对药剂愈敏感。幼虫死亡多发生在脱皮和化蛹阶段。少数幼虫进入蛹期后继续死亡或不能正常羽化,呈“半蛹一半成虫”态。幼虫期浸体法施药效果好于浸叶饲喂法。受药幼虫几丁质合成受抑,含量减少,内表皮变薄并出现剥离和断裂,脂肪体碎裂、崩坏以至消失。 The domestic 25% diflubenzuron suspension No.3 showed strong bioactivity to Pieris rapae L. in the concentration range of test (0.25-250ppm). Can inhibit egg hatching and lead to the death of newly hatched larvae, the younger the larvae, the more sensitive to the agent. Larval death occurs mostly in the stage of peeling and pupation. A small number of larvae continue to die after pupal stage or can not be normal emergence, was “half adult pupa” state. The larvae immersion method is better than the immersion leaf feeding method. The drug larvae chitin synthesis inhibited, reduced content, the inner epidermis thinning and peeling and fracture, fat body fragmentation, collapse and even disappear.