Inheritance mode and properties of fipronil resistance in Oxycarenus hyalinipennis Costa (Hemiptera: Lygaeidae)

The dusky cotton bug (DCB), Oxycarenus hyalinipennis Costa (Hemiptera: Lygaeidae) is one of the most important pests of cotton. Fipronil belongs to phenylpyrazole and is being used against various insect pests. To reduce the resistance to this insecticide, the present study was planned to examine the inheritance mode and preliminary mechanism of resistance to fipronil in DCB. A fipronil selected strain had a 9855-fold level of resistance after 11 generations of selection with fipronil. The median lethal concentration of reciprocal crosses F-1 (Fipro-Sel.male x Lab-Pop female) and F-1 (Fipro-Sel. female x Lab-Pop male) showed no significant difference and degree of dominance values were 0.60 and 0.58 for F1 and F1(-)), respectively, suggesting autosomal and incompletely dominance of resistance to fipronil in fipronil selected strain of DCB. Monogenic model of inheritance revealed polygenic resistance to fipronil. Realized heritability (h(2)) value was 0.24 for fipronil resistance. The study of synergism indicated that PBO (Piperonyl butoxide) and DEF (S, S-butyl phosphorotrithioateases) did not enhance the toxicity of fipronil on both populations. The study on inheritance mode of fipronil resistance in DCB may help delay the resistance with insecticides.