Effects of Ultrasound on Capture of Heliothis zea and Ostrinia nubilalis Moths in Traps Equipped with Ultraviolet Lamps

Moths of the bollworm, Heliothis zea (Boddie) (Lepidoptera: Noctuidae), and the European corn borer, Ostrinianubilalis (Hubner) (Lepidoptera: Pyraustidae), flying incorn field were attracted to and captured in traps equipped with ultraviolet lamps. Ultrasound speakers were so arranged in the light traps that the same airspace was covered by light and sound. Since on any given night only 2 of the 4 speakers produced ultrasound, the repelling effect of the various pulse rates of ultrasound could be measured. Ultrasound pulse repetition rates of 10–150/sec reduced capture of H. zea in the light traps by 75%; rates of 2/sec or less were less effective. However, when the captured bollworm moths (from bothsilent and ultrasound-emitting traps) were checked for acoustic sensitivity by electrophysiological methods, only 2–7% of moths were deaf in both tympana. More than 90% of the moths caught in the light traps with speakers emitting pulsed ultrasound were not deaf. Thus, moth deafness alone was not responsible for the moth catch in the light traps equipped with speakers emitting ultrasound. Pulse repetition rates of 10–28/sec and pulse durations of 3–10/msec were the most effective stimuli forcausing H. zea to avoid light traps with speakers emitting pulsed ultrasound. Ultrasound stimuli consisting of 25 kilohertz, 10 pulses/sec, and pulse durations of l0 milli seconds were the most effective in reducing the catch of O. nubilalis