Codling moth damage in the Hood River Valley is a major concern to pear growers. Several factors may be responsible for the increases in codling moth damage including resistance development, incorrect spray timing and the switch from organophosphate insecticides to more selective, but possibly less effective control alternatives. A major focus is determining if there is insecticide resistance present in the Hood River Valley. Codling moth populations were monitored for azinphosmethyl (Guthion) resistance in 2004. Several orchards were found to exhibit resistance compared to a known susceptible population. Orchards with potential resistance problems were identified by pheromone trap catches from several hundred trap locations. Resistance monitoring continued in 2005 in orchards with high codling moth populations. In addition to azinphosmethyl, resistance monitoring in 2005 also included the neonicotinoid insecticide acetamiprid (Assail), which is widely used as an organophosphate replacement for codling moth control. First generation codling moth males were collected with pheromone traps and tested for resistance by treating them with different concentrations of azinphosmethyl and acetamiprid. As in 2004, azinphosmethyl resistance was again detected in several orchards. Populations in some of these orchards also exhibited resistance to acetamiprid suggesting cross-resistance. Diapausing larvae were also collected in 2004 from orchards with high codling moth populations and treated with different concentrations of azinphosmethyl and acetamiprid to assess resistance. Diapausing larvae will be collected again to confirm results and evaluate other insecticides for potential cross-resistance.