Small-Plot Tests with Synthetic Juvenile Hormones on Alfalfa Weevil in Maryland and Pennsylvania

When synthetic juvenile hormones were field-tested in 1971 and 1972 in Maryland and Pennsylvania vs. 4th instars of Hypera postica (Gyllenhal), 1 compound significantly increased the mean weight of normal adults, and substantially increased the mortality of pupal-teneral adult weevils. A dose-mortality correlation was observed with 6,7-epoxy-3,7-dimethyl-l-(3,4-[methylenedioxy]phonoxy)-2-nonene, and repeatable biological activity was demonstrated at both locations, but the 2nd application often did not increase performance. At any given dose, fewer than 10% of the live adult weevils had morphogenic aberrations. No untimely ovipositional activity that indicated premature termination of adult diapause was observed.