Application of Near Infrared Laser in Controlling Locust

To broaden the range of laser's application, continuous near infrared semiconductor diode laser (wavelength 808 nm, power 2W) was used to evaluate the effect on Locusta Migratoria Manilensis locusts by laser irradiation. The heads of VI-V instar nymphs were irradiated at the 4 cm distance from the output light pane of laser and 2s /4s irradiation time respectively, and the activity of locusts was observed. The heads of I-III instar nymphs and VI-V instar nymphs were irradiated at different irradiation distances and time, and the death rate of locusts were noted two hours, two days and three days after treatment. The results indicated that the activity of locusts decreased to a lower level when power density of laser is less than tissue's thermal effect threshold (10 W/cm
²
), and the irradiation time was longer, the activity was lower. When power density nears the tissue's thermal damage threshold, the locusts were killed. Besides, the death rate was higher along with longer irradiation time, greater power density (nearer irradiation distance) and younger instar nymphs. At distance 3cm and time 2s, the death rate of I-III instar nymphs was 80% 3 days after irradiation. So, locusts especially before III instar nymphs can be killed easily if only suitable laser energy and wavelength are chosen. In this work, the results proved it's feasible to control locusts by laser irradiation.