Laboratory induced selection of pyriproxyfen resistance in Oxycarenus hyalinipennis Costa (Hemiptera: Lygaeidae): Cross-resistance potential, realized heritability, and fitness costs determination using age-stage, two-sex life table

Pyriproxyfen is a biorational insecticide from IGR family, used worldwide against several economic pests. To evaluate the risk of pyriproxyfen resistance in dusky cotton bug, Oxycarenus hyalinipennis Costa (Hemiptera: Lygaeidae), a major concern for cotton producers, and to formulate strategies effective to tackle resistance, a field collected population was selected with pyriproxyfen under laboratory conditions using seed-dip method. A resistant strain designated as Pyr-SEL (G(18)) was developed after repeatedly selecting O. hyalinipennis with pyriproxyfen over eighteen generations. Thereafter, fitness costs, realized heritability (h(2)) and cross-resistance were investigated. As a result of selection, Pyr-SEL (G(18)) developed a very high level of resistance (resistance ratio = 464.23-fold) compared with the susceptible strain unselected over twenty generations Un-SEL (G(20)). The Pyr-SEL (G(18)) conferred strong cross-resistance to bifenthrin (146.59-fold), lambda-cyhalothrin (132.96-fold) and fenoxycarb (91.06-fold), whereas showed moderate cross-resistance to diafenthiuron (28.86-fold) and fipronil (22.73-fold). The h(2) estimate was 0.16 in Pyr-SEL (G(18)). The developmental duration of O. hyalinipennis pre-adult prolonged, but traits of l, r and R-0 reduced in Pyr-SEL (G(18)) compared with the Un-SEL (G(20)). Also, the population projection obtained lower population size for Pyr-SEL (G(18)) than Un-SEL (G(20)). Fitness studies revealed that high resistance development to pyriproxyfen lowered the relative fitness of Pyr-SEL (G(18)) (Rf = 0.38) compared with the Un-SEL (G(20)). These findings may be practically valuable in tackling O. hyalinipennis resistance for better pest management. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

Pyriproxyfen resistance was evaluated in a field collected population of dusky cotton bugs, resulting in the development of a highly resistant strain (Pyr-SEL (G(18))) showing strong cross-resistance to other insecticides. Fitness studies indicated that high resistance development to pyriproxyfen lowered the relative fitness of the resistant strain compared to the susceptible strain.