EARLY DETECTION OF SIMULATED HERBIVORE ATTACKS IN SORGHUM FIELDS THROUGH THE DEPLOYMENT OF VERY-LOW-POWER GAS SENSOR NETWORK

Abstract

This paper reports a novel method of detecting simulated herbivore attacks (mechanical damages) on a plant by sensing emitted gas, which was enabled by developing and deploying a very-low-power gas sensor network in an actual sorghum farm. When a group of nearby sorghum leaves were cut (simulating herbivore attacks), the damaged plants started emitting a unique volatile organic compound (VOC) marker, hexanal, ultimately increasing its concentration up to 60 ppm in 62 minutes within an area of less than 1.0 m diameter from the cut point. The emitted hexanal was detected by a near-zero-power (<100 pW) gas sensor that utilized a nanogap structure to provide normally-dormant (thus minimal power consumption) but continuously sensing capability for hexanal. When the near-zero-power gas sensor detected the target gas in concentrations above a pre-set threshold (29 ppm), it connected an internal switch to flow power and wake up the rest of the circuitry including a micro-controller, a display module and a wireless module, ultimately sending an alert through the wireless network to a central station. This result demonstrated the first, within our knowledge, gas sensor network and actual field demonstration of early (stimulated) herbivore attacks. © 2022 TRF.