PLANT HEALTH DIAGNOSTIC METHOD AND PLANT HEALTH DIAGNOSTIC DEVICE
Provided are a plant health diagnosis method and a plant health diagnosis device enabling the detection of initial damage in a young individual plant suffering from pests or the like in a large-scale plant cultivation site. The method comprises diagnosing the state of health of a plant on the basis of chlorophyll fluorescence emitted from the chlorophyll in the plant body, wherein a first minimum point (s) occurring after a maximum point (p) where the chlorophyll fluorescence intensity is greatest, and a first maximum point (m) occurring after the minimum point (s) are determined on a temporal change curve of the chlorophyll fluorescence intensity
(S, M) are defined as the chlorophyll fluorescence intensities at the minimum point (s) and at the first maximum point (m) occurring after the minimum point (s)
and the values of (S) and (M) are compared to evaluate the state of the plant. The state of a plant, which cannot be visually confirmed by the outward appearance, can be detected by the comparison of the values of the chlorophyll fluorescence intensities (S, M), and therefore the state of an individual plant can be diagnosed at an early stage.