Rapid Detection of Colorado Potato Beetle Damage Using Small Unmanned Aircraft.

Remote sensing with small unmanned aircraft systems (sUAS) has potential applications in agriculture because low flight altitudes allow image acquisition at very high spatial resolution.  Damage to potato fields by the Colorado potato beetle (Leptinotarsa decemlineata) rapidly increases from initial infestations; early detection allows more options for integrated pest management and biological control.  We conducted an experiment on Ranger Russet potatoes at the Oregon State University Hermiston Agricultural Research and Extension Center (HAREC) with 4 levels of infestation (0, 1, 3, and 5 beetles per plant) and 4 replications arranged in a randomized block design.  Daily, we flew a quadcopter at three altitudes with a Tetracam, Inc. (Chatham, CA) Multiple Camera Array with 5 bands (blue, green, red, red-edge, and near-infrared) and one up-looking calibration channel.  Over three days, damage in some plots increased from 0 to 29%, with almost all of the damage becoming visible on the third day.  Damage was correlated with the total number of beetles (sum of released and immigrants) beetles). Plot-scale spectral vegetation indices were not well correlated with initial levels of damage, whereas plot heterogeneity of NDVI was best correlated. Simple algorithms of heterogeneity may be automated and do not require image mosaicing.  False positive detections will be frequent but manageable.