Physical Factors Influencing Orientation of Tyrophagus putrescentiae (Schrank) (Sarcoptiformes: Acaridae) to Food-Baited Traps

Abstract

Tyrophagus putrescentiae (Schrank) (Sarcoptiformes: Acaridae) is a serious pest of post-harvest durable stored food products for which traps are being developed as important tools for integrated pest management. This work addresses the effects of trap design, trap location, time of response, and light on the orientation of released groups of 7200 pedestrian T. putrescentiae to food-baited traps in experimental rooms maintained in full darkness at 28 °C and 70% RH. A standard trap made from a disposable Petri dish and four commercially produced stored-product pest traps of different designs were compared and evaluated for efficacy in trapping mites. Subsequent experiments evaluated the effect of trap placement, trapping duration, and light on mite capture. More mites were captured in the standard Petri dish trap when compared singly or side by side with four different commercial trap designs, so the standard trap was used in all other studies. Further experiments found that mites could be trapped 1 h after release at a distance of 2 m from the release point and at six meters from a mite source within 24 h. A greater number of mites were caught in traps placed along a wall than those away from a wall, demonstrating thigmotaxis to an edge. Traps at various heights on a shelf rack suggested that walking mites tended to be positively geotactic whether the source of mites was from the floor or from the top shelf at 1.8 m from the floor. More mites were caught in black-painted traps than in unpainted clear plastic traps in fully lighted rooms, suggesting that mites seek refuge from brightly lighted conditions. Light emitting diodes deployed with traps or assayed alone determined mites oriented positively to traps with violet or ultraviolet, with least preference to green, yellow, red and white lights. This research provides new information on orientation by T. putrescentiae that may help optimize trap designs and trap deployment for pest management decisions.