Effect on Locusts and Green Bristle Grass by 808nm Laser Irradiation

To explore new physical means in controlling locusts, near infrared semiconductor diode laser (wavelength 808 nm, power 2 W) was used to evaluate the effect on locusts and green bristle grass by laser irradiation. Locusta Migratoria Manilensis and fresh gramineous plant green bristle grass were chosen as experimental objects. To observe the death rate of locusts, the heads of I-III instar nymphs and VI-V instar nymphs were irradiated at different irradiation distances and time, and the results were noted two hours, two days and three days after treatment. To observe the growth state of green bristle grass after irradiation, the leaves and stems were irradiated at different distances and time. The results indicated that the locusts were killed when power density nears the tissue´s thermal damage threshold (10 W/cm²). Besides, the death rate was higher along with longer irradiation time, greater power density (nearer irradiation distance) and younger instar nymphs. At distance 3 cm and time 2 s, the death rate of I-III instar nymphs was 80% 3 days after irradiation, and the gross growth state of green bristle grass kept well. So, locusts especially before III instar nymphs can be killed easily and green bristle grass is not influenced if only suitable laser energy and wavelength are chosen. In this work, the results proved it´s feasible to control locusts by laser.