Capture rates of the European pine sawfly, Neodiprion sertifer, in pheromone traps, with special regard to effects of wind speed

Males of the European pine sawfly, Neodiprion sertifer Geoffr., were marked and released downwind from pheromone traps, baited with 100 mug of the sex pheromone (2S,3S,7S)-3,7-dimethyl-2-pentadecyl acetate. Males were release d 5 m downwind from one trap, or downwind from five traps, 50 m or 200 m aw ay. The average capture rates after 24 hr were 21.5%, 17.7% and 3.8%, respe ctively. The capture rate was highest at moderate wind speeds (1-2 m/sec) i n the 50 m experiments, whereas it decreased above wind speeds of 1.5 m/sec in the 200 m experiments. With no precipitation and > 13.5 degreesC during overcast, wind speed is presumably the most important climatic factor for N. sertifer males flying upwind to a pheromone source. Travel time, the ela psed time form take-off to landing on the trap, varied considerably, and th e shortest recorded travel times were 1, 6 and 45 min for the 5, 50, and 20 0 m experiments, respectively. The trap efficiency i.e., number of captured males per number of males that landed on the trap, was estimated at 52% in the 5 m experiments. The sampling range after 24 hr was calculated at appr oximately 400 m by regression analysis. The combination of the males' fligh t ability during upwind progress and their longevity (12 days), suggests a potentially large seasonal sampling range of the traps used in this study.