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) was developed after repeatedly selecting O. hyalinipennis with pyriproxyfen over eighteen generations. Thereafter, fitness costs, realized heritability (h) and cross-resistance were investigated. As a result of selection, Pyr-SEL (G) developed a very high level of resistance (resistance ratio = 464.23-fold) compared with the susceptible strain unselected over twenty generations Un-SEL (G). The Pyr-SEL (G) 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 estimate was 0.16 in Pyr-SEL (G). The developmental duration of O. hyalinipennis pre-adult prolonged, but traits of λ, r and R reduced in Pyr-SEL (G) compared with the Un-SEL (G). Also, the population projection obtained lower population size for Pyr-SEL (G) than Un-SEL (G). Fitness studies revealed that high resistance development to pyriproxyfen lowered the relative fitness of Pyr-SEL (G) (R = 0.38) compared with the Un-SEL (G). These findings may be practically valuable in tackling O. hyalinipennis resistance for better pest management.