VARIATION IN SUSCEPTIBILITY TO PYRIPROXYFEN IN 4 LABORATORY STRAINS OF PODISUS-MACULIVENTRIS (SAY) (HET., PENTATOMIDAE)

The susceptibility of four laboratory strains of the spined soldier bu g, Podisus maculiventris (Say), to the juvenile hormone mimic pyriprox yfen was examined in the laboratory. Fifth instar nymphs (<24 h old) w ere exposed to pyriproxyfen via ingestion of treated drinking water. L C50 values fora long-term laboratory strain originating from Florida ( FLO), a more recently introduced strain from Indiana (IND), and two mi ldly inbred strains (IS1, IS2) of the latter origin, were comparable, ranging from 39.8 to 61.6 mg a.i.. l(-1). However, slopes of dose-mort ality curves indicated that the susceptibility of the four populations of P. maculiventris decreased in order of IS2 > IS1 approximate to FL O > IND. The results of this study are discussed with respect to strai n maintenance and quality control of natural enemies used to test side -effects.