Effect of ultrasound on stem borer Sesamia nonagrioides

Mediterranean corn stalk borer (Sesamia nonagrioides) is one of the major pests in corn and sugarcane fields of Khuzestan province, southwest Iran. Application of ultrasound  for physical control of insect pest with hearing ability can be used as appropriate alternative for chemical control in integrated pest management program. In this study, repellency effect of different ultrasonic frequencies and wave shapes on the moth was evaluated using free-choice tests. Moreover, effect of the effective ultrasound on some biological characteristics and larval distribution patterns of the insect were studied in non-choice experiments. The frequency 40 KHz had the highest repellent effect for the moths. However, the wave shape did not significantly influence the repellency property. In frequency 40 KHz, longevities of 1st -3rd instar larvae were significantly reduced (4.97-8.33%). Furthermore, weights of all larval instars significantly affected by the ultrasound and reduced (3.61-12.66%). Investigation on the larval distribution pattern exposed to the ultrasound indicated that the larvae migrated from front of ultrasonic source and tended to escape from the ultrasonic source.  Results of the study implicated potential of the ultrasound for controlling S. nonagrioides population. However, the results of the laboratory study require field studies for validation.