OUTDOOR FLIGHT ACTIVITY AND IMMIGRATION OF RHYZOPERTHA DOMINICA INTO SEED WHEAT WAREHOUSES

Authors: TOEWS, MICHAEL; Campbell, James - Jim; ARTHUR, FRANKLIN; RAMASWAMY, SONNY - KANSAS STATE UNIV

Submitted to: Entomologia Experimentalis et Applicata
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/7/2006
Publication Date: 9/1/2006
Citation: Toews, M.D., Campbell, J.F., Arthur, F.H., Ramaswamy, S.B. 2006. Outdoor flight activity and immigration of Rhyzopertha dominica into seed wheat warehouses. Entomologia Experimentalis et Applicata 121: 73-85.

Interpretive Summary: The lesser grain borer, a serious pest of stored wheat, is currently managed with routine pesticide applications or fumigation with phosphine. An outdoor insect monitoring program was investigated that would allow pest managers to target pest control efforts when infestation pressure is high. Insect traps were positioned inside and outside Foundation wheat seed warehouses in Kansas and Nebraska to determine when and where the insects were immigrating into the facilities. Insects primarily entered the facilities under overhead doors and there were two peaks in insect capture, one in early spring and another in autumn. These studies demonstrated that outdoor-pheromone baited traps are effective monitoring tools for determining when grain-handling facilities are most susceptible to infestation and that exclusion around overhead doors may be an effective non-chemical component of a pest management program.

Technical Abstract: The flight activity of lesser grain borer, Rhyzopertha dominica F. (Coleoptera: Bostrichidae), was monitored at two Foundation wheat seed warehouses during the 2003 and 2004 field seasons, using pheromone-baited Lindgren funnel traps positioned indoors and outdoors. General stored-product insect activity was monitored also using unbaited sticky traps positioned inside the warehouses near overhead doors. The objectives of this study were to study seasonal patterns in R. dominica flight activity, determine periods of time when warehouses were susceptible to infestation from outside sources, investigate the importance of doors as routes of entry into warehouses, and test the effectiveness of exterior door gaskets around overhead doors for mitigating insect immigration. Pheromone traps were useful for monitoring R. dominica activity; however, the capture rates decreased when lures were not changed weekly. Large flight peaks were documented in early May and September through October, and insect captures inside warehouses were correlated with timing of outdoor captures. Multiple regression analyses showed that slightly more than half of the variability in R. dominica captures could be explained by ambient air temperature and wind speed 2 h before sunset. Stored-product Coleoptera captured on unbaited glue boards around overhead doors included Ahasverus advena, Cryptolestes ferrugineus, R. dominica, Sitophilus oryzae, Tribolium castaneum, Trogoderma variabile, and Typhaea stercorea. Door gaskets significantly reduced insect capture on glue boards placed around the overhead doors, and generally restricted their entry to ground level. These studies demonstrate that outdoor pheromone-baited traps are effective monitoring tools for determining when grain-handling facilities are most susceptible to infestation and that exclusion may be an effective component of a pest management program.