谷蠹的磷化氢抗性及其完全致死浓度与时间研究

STUDY ON PHOSPHINE RESISTANCE OF DIFFERENT RHYZOPERTHA DOMINICA(FABRICIUS) STRAINS AND THEIR COMPLETELY LETHAL CONCENTRATIONS AND EXPOSURE TIMES

采用FAO推荐的储粮害虫磷化氢抗药性测定方法,测定了2014年采自中国5个省9个地区(单位)谷蠹Rhyzopertha dominica(Fabricius)的磷化氢抗药性,并采用100、200、300、400、500m L/m3的磷化氢浓度,测试了害虫在不同时间的死亡率及其完全致死时间。试验结果为:来自广州市番禺区的谷蠹GZPYRd品系抗性系数为1;来自广州市东山区、福建省龙岩市、福建省漳州市、广州市花都区的GZDSRd、FJLYRd、FJZZRd和GZHDRd谷蠹磷化氢抗性系数(Rf)均小于50;来自河南省南阳市(HNNNRd)、山东省济南市(SDJNRd)、广西自治区南宁市(GXNNRd)和广州省岭南集团(GZLNRd)的谷蠹Rf分别为173.8、163.4、138.9和114.3倍,表现出了较强的磷化氢抗性。在100 m L/m3磷化氢浓度下,完全致死Rf为163.4的SDJNRd、Rf为114.3的GZLNRd和Rf为38的GZDSRd品系的相应时间为9.5 d、9 d和7.5 d;在磷化氢浓度为200 m L/m3时,完全致死SDJNRd、GZLNRd和GZDSRd品系害虫的时间均为5.5 d,浓度增加1倍,完全致死时间缩短近50%。磷化氢浓度在300 m L/m3以上,完全致死害虫的时间对于SDJNRd、GZLNRd和GZDSRd品系相应为4.5 d、4.5 d和4 d以内。结果表明,来自不同地区的谷蠹品系对磷化氢的抗性存在明显差异,即使在同一地区不同地点或单位采集的谷蠹对磷化氢的抗性差异也很大。100 m L/m3的浓度均可以完全致死弱抗性和较强抗性的谷蠹害虫种群,只是完全致死较强抗性谷蠹需要的熏蒸时间较长。磷化氢浓度升高可以缩短完全致死害虫的时间,但完全致死害虫时间与浓度的升高不成比例地相应缩短。不同磷化氢浓度完全致死同一谷蠹品系的Ct值不是一个固定数值,低浓度磷化氢完全致死害虫所需Ct值小,高浓度时完全致死害虫所需要Ct值大。

Phosphine resistance of nine Rhyzopertha dominica （Fabricius） strains collected from 9 areas of 5 provinces in 2014 was measured by the Food and Agriculture Organization （FAO） recommended method, and the mortality of each strain was investigated at different exposure times with phosphine concentrations of 100, 200, 300, 400 and 500 mL/m3 respectively. The results showed that the resistance coefficient of the GZPYRd strain （collected from Panyu, Guangzhou） was 1. The resistance coefficients of the GZDSRd （collected from Dongshan, Guangzhou） strain, FJLYRd （collected from Longyan, Fujian）, FJZZRd （collected from Zhangzhou, Fujian） and GZHDRd （collected .from Huadu, Guangzhou） were less than 50. The resistance coefficients of the strains of the HNNYRd （collected from Nanyang, Henan）, SDJNRd （collected from Ji＇nan, Shandong）, GXNNRd （collected from Nanning, Guangxi） and GZLNRd （collected from Lingnan, Guangzhou） were 173.8 ,163.4, 138.9 and 114.3, which had strong resistance to phosphine. The complete lethal time of SDJNRd （Rf=163.4）, GZLNRd （Rf=l14.3） and GZDSRd （Rf=38） strains were respectively 9.5 d, 9 d and 7.5 d at the concentration of 100 mL/m3, and accordingly 5.5 d, 5.5 d and 5.5 d at the concentration of 200 mL/m3 of phosphine. The complete lethal time was reduced nearly a half when phosphine concentration was increased 1 time. Furthermore, the complete lethal time for the strains of SDJNRd, GZLNRd and GZDSRd were respectively 4.5 d, 4.5 d and 4 d when the phosphine concentration was more than 300 mL/m3. These results indicated that R. dorninica strains collected from different regions had different levels of phosphine resistance. There even existed obviously different resistance levels for R. dominica strains collected from different areas in same region. Both weak and strong resistance strains of R. dominica could be completely killed with phosphine concentration of 100 mL/m3. The longer time was necessary for completely killing strong resistance strain. Althrough the complete lethal time can be reduced with higher phosphine concentration, there is a disproportionately corresponding relationship between the complete lethal time and increasing concentration. The C, value of different phosphine concentration for completely killing the same R. dominica strain was not constant. The lower phosphine concentration, the smaller value, and the higher phosphine concentration, the bigger value.