INSECT PESTS ASSOCIATED WITH RURAL MAIZE STORES IN MEXICO WITH PARTICULAR REFERENCE TO PROSTEPHANUS-TRUNCATUS (COLEOPTERA, BOSTRICHIDAE)

A survey was carried out into the occurrence of insect pests infesting rural stores in five regions of Mexico. Stores were sampled using phe romone-baited crevice traps, bait-bags and maize samples every 28 d fo r an entire storage season. Maize and store temperatures, and grain mo isture content were measured. The most numerous primary pests were Sit ophilus zeamais Motsch., Sitotroga cerealella (Olivier) and Prostephan us truncatus (Horn). P. truncatus was more abundant in stores in the d rier, temperate regions of Guanajuato, La Laguna and Jalisco than in t he more tropical regions, Veracruz or Chiapas. In La Laguna (and to so me extent in Jalisco), many more P. truncatus were detected in the sto re using the crevice trap than were counted in the maize samples, perh aps because crevice traps may attract beetles from outside the store. La Laguna and Chiapas had significantly fewer larvae of P. truncatus i n the samples than other regions, probably a result of the lower grain moisture content. Grain damage levels were very low in La Laguna and they occurred later in Guanajuato than elsewhere. The three pest speci es causing most damage were S. zeamais, S. cerealella and P. truncatus . It is suggested that P. truncatus was important in causing damage pr imarily in Guanajuato, whereas S. zeamais and S. cerealella caused mor e damage elsewhere, particularly in more humid areas.