Development of a PC-based automatic monitoring system for Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) in a rice warehouse

Flight traps were constructed and hung 6 m from the floor of a rice warehouse, with a 5 m polyvinyl chloride (PVC) tube attached to the base of each trap. The PVC tube channelled any Tribolium castaneum (Herbst) caught into a plastic specimen vial at the bottom. A pair of traps was placed at each of four designated locations in the warehouse. One of the pair of traps at each location had the vial resting on a top pan balance. The four balances were interfaced with an IBM-compatible personal computer. The signals from the balances were recorded as the weights of the insects by the computer sequentially and continually. The other trap at each location was set 1 m from the computer-controlled trap and acted as a reference trap. The insects collected from it were weighed manually on a daily basis. Trap catches using both methods were recorded for 50 days. The system was not influenced by temperature and r.h. changes, and dust fall was negligible. The weights of individual live beetles recorded monthly for 6 months did not change significantly. Thus the weights obtained during monitoring could be converted to the number of T. castaneum. A good correlation was obtained between the computer and manual trap catches, with a mean correlation coefficient of 0.898 (P < 0.001). These results demonstrate the feasibility of using a technique which monitors flight trap catches electronically and remotely.