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. 2019 Feb 20;44(1):41–47. doi: 10.1584/jpestics.D18-064

Fig. 1. Aerial ultrasonic conditions and an experimental flow. Seedlings of each plant were irradiated with ultrasound of 40.5 kHz frequency with ca. 100 dB sound pressure level. The oscillation pattern was composed of intermittent pulse waves. The pulse width is 7 msec, and the pulse frequency repeatedly shifts. The intermittent pulse waves are illustrated (a). Irradiation with ultrasound started when plants were 1 week old, continued for 1–2 weeks (24 hr a day), and plants were inoculated with pathogens at 0 or 1 week after terminating ultrasound irradiation (b). Tomato seedlings irradiated with aerial ultrasound in a limited irradiation area (50 cm diameter at 70 cm from the oscillator) in a sound-proof area (c).

Fig. 1. Aerial ultrasonic conditions and an experimental flow. Seedlings of each plant were irradiated with ultrasound of 40.5 kHz frequency with ca. 100 dB sound pressure level. The oscillation pattern was composed of intermittent pulse waves. The pulse width is 7 msec, and the pulse frequency repeatedly shifts. The intermittent pulse waves are illustrated (a). Irradiation with ultrasound started when plants were 1 week old, continued for 1–2 weeks (24 hr a day), and plants were inoculated with pathogens at 0 or 1 week after terminating ultrasound irradiation (b). Tomato seedlings irradiated with aerial ultrasound in a limited irradiation area (50 cm diameter at 70 cm from the oscillator) in a sound-proof area (c).