An optical system to detect, surveil, and kill flying insect vectors of human and crop pathogens.

Sustainable and effective means to control flying insect vectors are critically needed, especially with widespread insecticide resistance and global climate change. Understanding and controlling vectors requires accurate information about their movement and activity, which is often lacking. The Photonic Fence (PF) is an optical system that uses machine vision, infrared light, and lasers to identify, track, and interdict vectors in flight. The PF examines an insect's outline, flight speed, and other flight parameters and if these match those of a targeted vector species, then a low-power, retina-safe laser kills it. We report on proof-of-concept tests of a large, field-sized PF (30 mL × 3 mH) conducted with Aedes aegypti, a mosquito that transmits dangerous arboviruses, and Diaphorina citri, a psyllid which transmits the fatal huanglongbing disease of citrus. In tests with the laser engaged, < 1% and 3% of A. aegypti and D. citri, respectfully, were recovered versus a 38% and 19% recovery when the lacer was silenced. The PF tracked, but did not intercept the orchid bee, Euglossa dilemma. The system effectively intercepted flying vectors, but not bees, at a distance of 30 m, heralding the use of photonic energy, rather than chemicals, to control flying vectors.

Optical tracking and laser-induced mortality of insects during flight.

Addressing the need for novel insect observation and control tools, the Photonic Fence detects and tracks mosquitoes and other flying insects and can apply lethal doses of laser light to them. Previously, we determined lethal exposure levels for a variety of lasers and pulse conditions on anesthetized Anopheles stephensi mosquitoes. In this work, similar studies were performed while the subjects were freely flying within transparent cages two meters from the optical system; a proof-of-principle demonstration of a 30 m system was also performed. From the dose-response curves of mortality data created as a function of various beam diameter, pulse width, and power conditions at visible and near-infrared wavelengths, the visible wavelengths required significantly lower laser exposure than near infrared wavelengths to disable subjects, though near infrared sources remain attractive given their cost and retina safety. The flight behavior of the subjects and the performance of the tracking system were found to have no impact on the mortality outcomes for pulse durations up to 25 ms, which appears to be the ideal duration to minimize required laser power. The results of this study affirm the practicality of using optical approaches to protect people and crops from pestilent flying insects.

Laser induced mortality of Anopheles stephensi mosquitoes.

Small, flying insects continue to pose great risks to both human health and agricultural production throughout the world, so there remains a compelling need to develop new vector and pest control approaches. Here, we examined the use of short (<25 ms) laser pulses to kill or disable anesthetized female Anopheles stephensi mosquitoes, which were chosen as a representative species. The mortality of mosquitoes exposed to laser pulses of various wavelength, power, pulse duration, and spot size combinations was assessed 24 hours after exposure. For otherwise comparable conditions, green and far-infrared wavelengths were found to be more effective than near- and mid-infrared wavelengths. Pulses with larger laser spot sizes required lower lethal energy densities, or fluence, but more pulse energy than for smaller spot sizes with greater fluence. Pulse duration had to be reduced by several orders of magnitude to significantly lower the lethal pulse energy or fluence required. These results identified the most promising candidates for the lethal laser component in a system being designed to identify, track, and shoot down flying insects in the wild.