Factors influencing the capture of Japanese beetles : wind speed and direction, trap deployment protocol, lure type, and trap efficiency

Abstract

In this study, factors affecting Japanese beetle (JB) trap captures (eg wind direction and speed, lure type, trap deployment and efficiency) were investigated in the field using semiochemical baited traps. Fifty-two percent of 667 JB observed flew directly upwind toward a trap with a dual lure (sex pheromone + floral kairomone), especially when wind speed exceeded 1.5 m/s. Within thirty seconds after approaching 2 m of a trap baited with a dual lure, 43%, 35%, and 22% of 138 observed beetles were captured, flew away, or landed on the trap, respectively. Of 265,884 beetles captured, 48% were captured by a cluster of 3 traps each with a single dual lure, 30% by a single trap baited with 3 dual lures, and 22% by a single trap baited with one dual lure. Traps baited with the floral lure (ie kairomone) and the floral lure and the sex pheromone (ie dual lure) captured similar numbers (39% and 41%, respectively) of JB and both captured more beetles than traps baited with the pheromone alone (12% and 8% for the sex-pheromone from the dual lure and sex-pheromone standard, respectively). Traps baited with the floral kairomone alone or with sex pheromone captured a 1:1 sex ratio (M:F) while pheromone-only traps captured a 3:1 (M:F) ratio of JB. No additive or synergistic effects of the pheromone and floral kairomone were observed. To our knowledge, this study is the first to quantify in real time the flight behavior of a beetle toward traps in the field.