When 4 methods of sampling to determine larval populations of Hypera postica (Gyllenhal) were compared, all of them produced essentially the same ranking of 8 treatments of azinphosmethyl. The sequential stem method of sampling (% of stems infested × number of larvae per infested stem × number of stems per ft2) recovered about 90% of the actual population and thus provided the most accurate estimate. Eight or 9 sweeps with a 15-inch net were required to produce the same estimate. D-Vac sampling recovered 19-25% of the actual population, and pan sampling recovered 29-38%.