Fifth instar Plodia interpunctella (Hübner) larvae were exposed for 0, 1, 3, 6, 12, 18, 24 and 30 hours on concrete treated with 0.0013 mg active ingredient [AI] / cm2 of the juvenile hormone analog hydroprene. Larvae were exposed at 16, 20, 24, 28 and 32ºC, and there were five replicates for each treatment combination. After the larvae were exposed, they were removed from the treated concrete and held at the same temperatures until adult emergence.

Larval development time progressively decreased as the temperatures increased from 16 to 32ºC but increased as the exposure periods increased from 0-30 hours within the individual temperatures. The longest development time of 35 days was observed at 16ºC and the shortest development time of 16.5 days at 32ºC. A polynomial model described the relationship between larval development time, exposure period and temperature. No larval mortality occurred at 16ºC when the larvae were exposed only for 1 hour while above 16ºC, the mortality increased along with increasing temperatures and also with increased exposure periods. The highest mortality of 80% was observed when larvae were exposed at 32ºC for 30 hours. A polynomial model was used to describe the relationship between mortality, exposure period and temperature.