【摘要】 本文报道印楝素对亚洲玉米螟Ostrinia furnacalis Guene幼虫生长发育的抑制作用和引起幼虫各器官的病变症状。用含20ppm印楝素的人工饲料饲喂亚洲玉米螟3—4龄幼虫2天,然后换入正常饲料,可使幼虫期显著延长,最后不能化蛹而死亡。印楝素对幼虫的作用是缓慢的,虫体受药后还可发育一个龄期。处理幼虫的行为失常,取食动作逐渐消失,主要靠消耗体内的水分和脂肪来维持生命。幼虫的胸足变黑,胸部出现褐色斑,这些部位的表皮分层不正常,真皮细胞坏死或自溶。处理幼虫的大脑萎缩,生殖器官和前胸腺肿大,前胸腺细胞膜厚而松散,血淋巴中β-蜕皮酮含量显著降低。从整个中毒症状来看,印楝素可能作用于亚洲玉米螟幼虫的神经和内分泌系统,从而逐渐引起各器官的病变。更多还原

【Abstract】 A seres of experiments were conducted on the effects of azadirachtin at concentration of 20 ppm mixed with artificial diet on the growth of the larvae of the Asiatic corn borer Ostrinia furnacalis Guenee. The third or fourth instar larvae were fed with the diet containing azadirachtin for two days, then, the normal diet was given. Results of our experiments show that, after treatment, the larval period was markedly prolonged, pupation was inhibited, the larval body shrank gradually, the fat content reduced and black thoracic leg and brown thoracic spot were observed. The treated larvae finally died. Upon examination with light and electron microscopes, it was found that the fat body of the treated larvae appeared abnormal, necrosis was found in the epidermal cells of thoracic legs and the thoracic epidermal cells disappeared, the cuticle did not show clear layers, the ovaries and testes swelled markedly. The prothoraeic gland cells greatly expanded and, the cell membrane became thicker and looser. The content of the β-ecdysone in the hemolymph of the treated larvae determined by ra-dioimmunoassay was markedly tower (6.36pg/μl) than the control (49.76 pg/μl). Our observations showed that the nerue and endocrine systems of the larvae were affected by azadirachtin.更多还原