^(60)Co-γ辐射对尼氏钝绥螨抗多虫畏性状的诱导及其它生物学效应

THE INDUCED PYRETHROID-RESISTANCE AND OTHER BIOLOGICAL EFFECTS BY ^(60)Co-γ RADIATION ON Amblyseius nicholsi EHARA et LEE(Acarina: Phytoseiidae)

本文首次报道了^(60)Co-γ射线辐射诱导抗药性产生的方法,以2000拉德(rad)的剂量辐射3次,约1年时间培育出尼氏钝绥螨Amblyseius nicholsi Ehara et Lee对拟除虫菊酯农药多虫畏具抗性的两个品系:单抗1(FR1)与双抗(PFR)品系。多虫畏对其致死中浓度LC_(50)由敏感品系的8.22×10^(-5)ppm分别提高到1.3347×10^(-3)和1.4307×10^(-3),抗性水平提高24.16和24.83倍,比直接用农药筛选出的两个品系——单抗1(PR1)与三抗(PDFR)品系的培育时间(27个月)缩短一半以上。FR1,FR2及PFR对常用的几种拟除虫菊酯农药:敌杀死,灭扫利、兴棉宝及来福灵均有一定的交互抗性(3—8倍),其LC_(50)比这些农药田间施用浓度要高3—23倍,为抗性品系的田间利用提供了条件。通过观察辐射的生物学效应再次证实该螨为拟单倍体种(Parahaploid)这一特征。

This paper reported: 1. The 60Co-r radiation induced pyrethroid-resistance of predatory mite, Amblyseius nicholsi, an important natural enemy of citrus red mite Panonychus citri. 2. Some other biological effects of 60Co-r radiation on A. nicholsi. The LC50s of S-5439 (a pyrethroid insecticide) to the two strains, FR2 and PFR which were radiated three times with 2000 rad (dosage rate= 140 rad/ min) of r-ray and selected with S-5439 for 12 months, were 1.3347× 10-3 and 1.4307× 10-3 ppm respectively, and were about 23-fold compared with that of the sensitive strain. And the selecting periods of FR2 and PFR were shorter than half that of FR1 and PDFR which were selected only with S-5439 for 27 months. FR1, FR2 and PDFR were all performed some extent cross-resistance to other pyrethroid insecticides. The LC50s of the tested pyrethroids to FRK FR2 and PFR were higher than their application concentrations in fields. It will be desirable for the practical utilization of these resistant strains in biological control of pest mites. The results of radiation genetics suggested that A. nicholsi might be a parahaploid species. The increase of 60Co-r dosage resulted in the decrease of sexual ratio (: ). The RLD50s (Medium Radiation Lethal Dosage) of F1 eggs estimated from the obtained data were different in the two cases of radiating only male father or both male and female parents.