Technical Abstract: In 2005, captures of overwintered adult plum curculio, Conotrachelus nemuphar (Herbst) (Coleoptera: Curculionidae), in standard black masonite pyramid traps baited with known attractants did not result in significant captures compared with unbaited traps as they had in 2003 and 2004. These baits included the synthetic aggregation pheromone, grandisoic acid (GA) alone, a 6-component systhetic host plant volatile combination identified from foliar and woody tissues of a Stanley plum tree (6-Tree) in combination with GA (6-Tree+GA), and the synthetic fruit volatile benzaldehyde (BEN) in combination with GA (BEN+GA). In 2005, the average daily temperature was below 13 degrees C, much cooler that in 2003-2004, We hypothesized that plum curculio could not discriminate between baited and unbaited traps because of reduced release rates of odor-bait stimuli due to their temperature-driven release system. Based on data collected from 2003-2005, we found that plum curculio captures in traps baited with GA alone, 6-Tree+GA, and BEN+GA were significantly related to temperature, and we created a predictive model to determine the level of activity, i.e. trap captures in baited traps compared with unbainted traps we would expect to observe at a particular temperature for these same odor stimuli. Our models predict that at temperatures between approximately 11 degrees C to 13 degrees C we would expect to see no difference between captures in baited and unbaited traps. For captures in odor-baited traps to reach twice those in unbaited traps, our model predicts that temperatures must reach 19.2 degrees C for GA alone, 18.5 degrees C for 6-Tree+GA, and 15.8 degrees C for BEN+GA.