Effects of modified atmospheres, temperature and humidity on the growth and development of Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) in feihe infant milk powder

Tribolium castaneum (Herbst) is a common stored product pest that damages various stored goods across the global. To identify the effects of modified atmospheres (MA), humidity and temperature on the growth and development of T. castaneum in Feihe infant milk powder, the modified atmospheres were set at 75% nitrogen (N₂) and 25% carbon dioxide (CO₂), with air as the control. Two different temperatures and humidities were set at 30 °C, RH 80% and 25 °C, RH 40%. The results revealed that T. castaneum larvae exposed to the warm and moist southern conditions (30 °C, RH 80%) feeding on flour and yeast diet had a significantly shorter developmental duration. The larval weights were significantly increased in T. castaneum feeding flour and yeast diet compared with those of T. castaneum feeding milk powder under high temperature. The elevated temperature significantly increased the mortality of larvae. However, 4.4% of the survival larvae successfully grow into adults at the cool and dry northern conditions (25 °C, RH 40%). The mortality rate of eggs was 100% when eggs were sealed and treated by MA under warm and moist temperature and humidity for 96 h, and the mortality rate of 5th instar larvae increased to 100% on 7th day. Moreover, the activities of CAT and GST were decreased in all stages of T. castaneum feeding on infant milk under temperature and humidity stress. Additionally, 5th instar larvae fed with infant milk powder showed significantly fluctuated activity of POD, SOD and P450 in all stages of T. castaneum. However, T. castaneum is more susceptible to milk powder sealing with air under warm and moist temperature and humidity. The present investigation demonstrated that temperature treatment and modified atmospheres effectively prevented growth and development of T. castaneum in milk powder. These results also contribute to suitable strategies for storage of milk power.