Remote imagery aids in detecting and managing plant disease

The ability to observe the health of a field from images taken remotely by satellites or aircraft may have a positive economic and environmental impact on plant disease management, say plant pathologists with The American Phytopathological Society (APS).

According to Karl Steddom, associate research scientist at the Texas Agricultural Experiment Station in Amarillo, Texas, “remote sensing” in plant disease management is the practice of gathering information about a crop’s health without physically scouting the field. Typically, this occurs through images captured from aircraft or satellites, but there are also ground-based applications. “The ability to view images of an entire field provides plant pathologists with greater precision and accuracy in disease assessment,” he said. “By using remote imagery to differentiate between healthy and diseased plants, we are then able to determine how many acres are impacted by a particular disease,” said Steddom.

Researchers first used remote sensing to differentiate between healthy and diseased crops in the late 1920s after U.S. Army pilots reported that cotton root rot spots were readily visible from the air at high altitudes. These spots were then photographed by hanging a camera over the side of the aircraft. The stark contrast between healthy cotton plants and the bare soil where the pathogen had killed the plants made the spots stand out in the photographs and the vertical angle allowed for comparative measures of healthy and diseased acreage.

Remote sensing has the potential to save time previously spent randomly scouting fields for potential disease. “Using images captured remotely enables us to identify those areas that need closer surveillance,” said David Jones, research associate at the Texas Agricultural Experiment Station in Amarillo, Texas.

By targeting the area that is infected, farmers can spray the areas that are affected rather than the entire field. “This reduces the amount of pesticide that is applied and the number of applications needed, reducing the cost of treatment and possible harm to the environment,” said Jones.