Insect infestations of post-harvest products can occur at any stage after a commodity leaves the field, including in storage facilities, processing plants, warehouses, and retail stores. Long-term monitoring of these insect pests can provide information on their ecology and behavior and inform integrated pest management programs to maintain food quality more safely and with less lost product. High levels of spatial and temporal variation have been shown to occur over relatively short-term scales but understanding long-term patterns within a food processing facility could reveal patterns that provide better predictability for pest management programs. Ten years of insect trap capture data was analyzed and evaluated for influences of environmental variables and for spatial dynamics for two insect species, Trogoderma variabile, the warehouse beetle and Plodia interpunctella, the Indian meal moth. Both species are commonly found in food and seed processing and storage facilities and can be destructive to stored commodities. Here we assess environmental variables including temperature on insect trap captures as well as underlying spatial variation across years and within years.
Results/Conclusions
We found that the Indian meal moth and the warehouse beetle did not commonly occur in the same spatial areas and Indian meal moths were more reliably caught in the same traps over time compared to warehouse beetles. Indian meal moths were caught most consistently where the facility was open from floors 1-4, where the insects could fly easily. We also found that temperature was the best environmental variable that predicted increases in populations of both species. Increases in warehouse beetles from 0 insects per trap started to occur at a maximum daily temperature of 21.1oC and occurred at a maximum temperature of 19.4oC for Indian meal moths. Fumigation of the facility resulted in rapid declines but fumigations in warm months had a quick rebound in insect populations. These results indicate that monitoring Indian meal moths in locations where populations are consistently captured will provide enough information for population management decisions but monitoring warehouse beetles must occur across the spatial scale of the facility to track these pests efficiently. Pausing monitoring efforts throughout the cool months may also save money and time, and restarting monitoring when temperatures reach predicted thresholds will provide suitable information on insect populations and treatment options.