Investigation of mortality rate of Drosophila melanogaster irradiated with nanosecond passively Q-switched microchip laser

Abstract

Lasers have been widely used for pest control because they are efficient and effective to kill pests. Efficient pest control has been achieved with pulsed lasers, however, there is less investigation of effects of pulse characteristics on the pest mortality. Here, the effects of laser beam diameter, pulse width, peak power, and repetition rate of a compact passively Q-switched microchip laser on the mortality rate of Drosophila melanogaster have been studied. The lethality dosing for 90% mortality rate (LD90) Drosophila melanogaster has been utilized for evaluating the effects of passively Q-switched laser on mortality of insects. The beam diameter comparable to the size of Drosophila melanogaster is effective and economic for killing insects. The energy fluence required for LD90 decreases about 6.5% as pulse width is shortened from 1.5 ns to 850 ps. The energy fluence required for LD90 decreases about one-third as the peak power of passively Q-switched microchip laser increases four times from 6.94 kW to 27.48 kW. The energy fluence required for LD90 decreases dramatically from 16.02 J/cm2 to 12.77 J/cm2 as repetition rate increases from 5.05 kHz to 9.9 kHz and then tends to keep as a constant around 12.7 kHz with further increase of repetition rate. Nanosecond passively Q-switched microchip laser with high peak power and high repetition rate is a promising light source for effective and efficient pest control.