Understanding geographic and host range expansion of stored product insects to improve quarantine and pest management programs.

Many species of stored product insects have been spread by commerce, a few recently enough to have a written record. The bean weevil, Acanthoscelides obtectus (Say), Mediterranean flour moth, Ephestia kuehniella (Zeller), and Angoumois grain moth, Sitotroga cerealella (Olivier), have some of the most complete early records. The larger black flour beetle, Cynaeus angustus (LeConte) may have the most complete record of both geographic and host range expansion. The introduction of heated buildings and storage sites has allowed tropical species to establish in temperate climates. The adoption of combine harvesting has increased the prevalence of insect pests requiring grain damage such as the saw-toothed grain beetle, Oryzaephilus surinamensis (L.). Relatively few pest introductions result in establishment, but repeated introductions are common, increasing the chances of establishment. Preharvest infestation, diapause, and survival on food residues in the grain marketing system and other foods in natural habitats have increased the likelihood of establishment. Introduction of containerized shipping in the late 1960s may have reduced cross infestation of cargoes, provided containers were fully disinfested prior to loading. Remote monitoring may be necessary as an alternative to opening each container for early detection of infestations. The importance of limiting importation of pesticide resistant strains is mentioned often but there are few papers on practical implementation of such programs. Movement of natural enemies with stored commodities is common and this has resulted in their wide geographical distribution. Knowledge of geographic and host range expansion can be important for development of quarantine and pest management programs.