Laboratory Trapping Studies with Sitophilus zeamais (Coleoptera: Curculionidae)1

Corrugated cardboard traps (Storgard®, Trece, Salinas, Calif.) were used to test attractive properties of combinations of synthetic pheromone and various food odors to maize weevils, Sitophilus zeamais Motschulsky, in laboratory test arenas. In both two- and four-choice tests, maize weevils preferred the (4S,5R) isomer of 5-hydroxy-4-methyl-3-heptanone (sitophinone) to the other three isomers. Cracked wheat was a stronger attractant than either whole wheat, wheat germ oil, or water. A strong synergistic effect between the (4S,5R) isomer and cracked wheat was demonstrated. Maize weevils were successfully lured out of a food source only when both cracked wheat and (4S,5R)-sitophinone were present in the trap. Only a slight reduction in catch was observed as weevils aged.