灭幼脲对粘虫幼虫的毒力和中毒症象的分析

TOXICITY AND SYMTOMATOLOGY IN THE ANALYSIS OF THE TESTING INSECT, MYTHMINA SEPARATA (WALKER)

■经灭幼脲处理后的中毒症象及灭幼脲对粘虫的毒力。

Treated with Diflubenzuron (DFB) at early instar, the oriental armyworm larvae(instar 3—5), normal developmental process of which were disrupted, died of failure to molting. Molt disruption can also occur during the larvalpupal molt. Retention of the last instar head capsule on the pupa resulted in a larval-pupal intermediate, which is the same as juvenile hormone analog induced symptom.Granett, J. et al. (1980) measured the Percentage of ingested DFB which was absorbed through gut into hemocoel of the western spruce budworm and douglas-fir tussock moth, these species absorded only 10 and 16％, respectively, of ingested DFB in 24 hr. The bulk of the ingested DFB passed through the gut-apparently without being absorbed or metabolized. Ivie, G. et al. (1978) measured various levels of DFB in the house-fly and the stable-fly, after cuticular treatments of the material in acetone, only 1％ or less of applied DFB was Present within the insects after 24 hr. In consideration of the oriental armyworm with 6—7 days for the 6th instar, treatment during the 1st day of the last larval instar resulted in delayed expression of Symptom until adult emergence and reproduction causing eggs failing to hatch. Since (1) DFB was excreted quickly, (2) these was no direct inhibited symptom in contact site, and (3) toxicity of DFB was Permanent and most symptoms appeared in relation to metamorphosis, it is suggested that the mechanism of toxicity of DFB is an interference to dynemic of hormone.