Drones using infrared imaging for detailed reports

When infrared filters are applied to the high definition photo on the left, this diseased chrysanthemum — with yellow areas in center, as seen in the inset image, and in the center of the larger photo — immediately stands out from its numerous neighbors. (Photos courtesy of Kirk Floyd, KDrone Services)

DAMASCUS, Md. — In the current fraught coronavirus environment, perhaps you’ve heard about the new calibrated infrared technology that’s being used at overseas airports to measure and screen passengers’ temperatures in real time.
That technology has also made an entrance into our region’s agriculture and horticulture industries.
Over the last year, the University of Maryland Extension has been working with Kirk Floyd, owner and chief pilot of KDrone Service to discover not only new ways to safely apply sprays to nursery stock, particularly field planted trees, but also pick up early signs of plant distress across multiple acres.
The latter is where the use of infrared technology comes into play.
Like people, evidence of plant damage from disease or other stressors shows up as hot spots on infrared imaging.
Thus, using infrared cameras mounted on a drone, Floyd can, for example, fly over a field full of hundreds of potted chrysanthemums and determine which ones are under stress from either disease or insects.
This is critical because “once damage begins to show on the plants, then that crop is unsaleable,” said Stanton Gill, Principal Extension Agent in entomology and Integrated Pest Management of UM.
Infrared cameras mounted on drones can also be used to monitor large in-field irrigation systems and detect any water leaks when they occur. In this instance, any water leaks will cause the soil to be cooler than the areas around it and the infrared camera will pick those leaks up as a blue color on the resulting image.
Similarly, multispectral and RGB (Red-Green-Blue) cameras can be mounted on a drone to also detect plant disease and stress problems after the resulting photography is run through the appropriate computer algorithms.
Such techniques become “an effective scouting tool,” explained Floyd, “because although they won’t tell you what the disease or pest stress is, they will tell you where it is.” When you’re dealing with hundreds or thousands of plants spread across tens or hundreds of acres, locating individual problem plants early is, of course, more than half the battle.
Once you’ve identified the problem, a spray drone can then be used to “precision apply the appropriate treatment,” said Floyd. “Of course, the biggest advantage is that people are not involved in the application area,” he continued.
Indeed, thanks to a grant, this is an area that Floyd and Gill, along with the assistance of UM plant pathologists, Dr. Karen Rane and David Clements, have been able to make considerable progress on during last year’s season by going into different size tree nurseries and testing the coverage using water and water sensitive papers.
The testing revealed interesting tidbits: “We found the nozzle type makes a big difference in coverage,” stated Floyd.
He also highlighted that coverage goals can vary depending on what’s being applied. For instance, while explaining the results of one of their successful nursery tree runs, Floyd noted, “We felt it was pretty good coverage, although Dave and Karen would have liked the card to basically be blue.”
He also pointed out that “with a pesticide drone operator, there’s a lot at stake, including a lot of liability,” if you’re working with an operator who doesn’t have the requisite background and experience. Both he and Gill encouraged nursery owners and farmers who were looking into the technology to research the pilot certification requirements as well as vet thoroughly any independent contractors they decide to engage.
“If an operator doesn’t know what they’re looking at or don’t understand the plant maps they’re constructing, the information is useless,” said Floyd, who also has extensive first-hand experience in the landscape and nursery industries. “Making sure that your contract guys know what they’re doing,” explained Floyd, includes ensuring they have not only all the necessary pesticide certifications, but also a remote pilot license — yes, you must have one from the Federal Aviation Administration to operate a drone in furtherance of a business — to protect you, your staff, and your plants.