The use of automated imaging systems providing close-up visual and thermal images of growing crops could provide early detection of plant pest and disease problems even before the appearance of visible symptoms.
Cameras and computer systems are available off the shelf and camera mountings can be attached to overhead glasshouse structures, although installation would be a major investment. HDC studentship project CP 60 tested the feasibility of this technology and informed the delivery of custom software for improved detection of individual thermal crop anomalies relative to the normal background temperature of the healthy crop.
Trays of bedding plants were partly shielded with plastic covers during irrigation and were therefore under stress. The effects were observed under suitable conditions but thermal effects due to pest attack or disease infection were not demonstrated. But it should be feasible to detect disease effects where they involve significantly reduced plant transpiration rates.
Separating the useful information in the images collected by the thermal camera from background "noise" was challenging. Results so far showed that detection of even very small temperature differences in plants was feasible. However, images collected under bright sunshine were fine but those taken under low light conditions presented a major challenge. The development of custom software capable of automatically distinguishing thermal effects indicative of plant disease from background noise effects will be essential for successful application of thermal imaging.
Horticultural Development Company
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