Message Board Thread - "Detection of diseased trees and plants "

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Detection of diseased trees and plants Gary Orlove 7/11/2000
Does anybody have information on the use of infrared cameras for the inspection of trees and plants for diseases?
RE:Detection of diseased trees and plants Gary Orlove 9/5/2000
Most of the literature available on this topic deals with reflected near infrared from the sun. However there are a few references to the use of a thermal infrared camera for detection of stressed and diseased plants. Please take a look at the following:

Crops under stress detected by infrared imaging Moisture stress during crop production might not be detected by human eyes, particularly during a moderate water shortage, such as that caused by the partial blockage of irrigation tubes in greenhouse vegetable production.

A technique has been developed to use an infrared imaging system for early detection of plant stress. Infrared images display an increase in foliar temperature in water- stressed plants before wilting is visible detect decay early in winter squash during storage.

This nondestructive, noncontact method is useful in plant science research and commercial greenhouse production. See

Color Infrared Films are being used or have been used in agricultural and forest surveys for the detection of crop yields, crop and tree diseases, and insect pests in forests and orchards, as well as in the identification of tree species. For example, changes in infrared reflectance have been used to detect diseased trees in citrus groves and to pick out elms infested by the Dutch elm disease.

Forest Survey
Aerial photographs of foliage made with color infrared-sensitive films often show great variations in infrared reflectivity even when leaves visually show just small variations in shades of green. Although there is a similarity in visual color between deciduous and evergreen trees, healthy deciduous trees have a much higher infrared reflectivity than healthy evergreens. As a result there are significant differences between the colors of these trees as recorded on these films. Also, these color differences are most important in differentiating between healthy and sick specimens. Experienced photointerpreters also take into account the size and shape of the objects as well as color differences when making interpretations. (Shape and size differences are more apparent when stereo pairs are viewed.) Generally, in spring and summer, healthy deciduous trees photograph magenta or red, and healthy evergreens photograph brownish red. Dead or dying deciduous leaves or evergreen needles usually photograph anywhere from dark red to green or even yellow. The leaves of deciduous trees, which turn red or yellow in autumn, still retain some of their infrared reflectivity for a while. Consequently, red leaves may photograph yellow, and yellow leaves may photograph white. In any given vegetation, the season, the water and mineral content of the soil, and the age and health of the vegetation may cause its infrared reflectance to vary. In fact, the first sign of a distressed tree (or plant) is often a decrease in infrared reflectance, which frequently first becomes apparent in color infrared photography.

Heat is on for plant disease diagnosis

Anyone who has had a bout of flu knows that high temperature and fever often presage illness. Now an analogous phenomenon in plants has been exploited by researchers to predict infection in tobacco before any other outward disease symptoms are detectable on the plants. Using an infrared video imager, researchers at the University of Ghent in Belgium have noted temperature hot spots around virus-infected leaves eight hours before any signs of disease are visible. Their infrared technology could be useful for rapidly diagnosing plant pathogen infection, studying plant--pathogen interactions, and ultimately selecting pathogen-resistant plants in crop-breeding programs.

Dominique Van Der Straeten and her colleagues had previously noted that the accumulation of salicylic acid, a defense molecule produced by plants in response to infection, appears to affect leaf temperature. In the present study, they confirm that the accumulation of salicyclic acid in the leaves of tobacco plants infected with tobacco mosaic virus results in local temperature elevations of 0.3--0.4 C that can easily be imaged using a high-resolution infrared camera. When they looked at the phenomenon more closely, the temperature hike appeared to be due to the closure of stomata---pores on the leaf surface that regulate the release of water (rather like human sweat glands). Salicylic acid appears to induce stomata closure, thereby preventing water loss and leading to the rise in temperature. The authors suggest that the nondestructive and predictive aspects of the approach will be of wide use for the early detection of plant diseases. See

Strains of specific stresses, such as water, have been succesfully sensed nonvisually by relating thermal infrared emissions to the water and energy balance of the plant. It is suggested that existing techniques may provide evidence of nonvisual strain, but they must be interpreted with a thorough understanding of the physiological alterations of stressed plants. See
Re:Detection of diseased trees and plants Chas 3/3/2004
I was unable to access the first three links in your post. One said the search engine ShopNav was unable to find the address, and the last two were 404 errors.
I am an aspiring thermographer, but have been involved in agriculture for all of my life. I am glad to see some articles steering towards this industry. thanks.
Trees, no leaves, looking for more info Coen T Service Netherlands 11/4/2004
Hello. recently I visited a workshop were one of the speakers was Mr.Catena. He told that by looking to the wood of a tree and by it's temperature differences you could find ill trees. he was looking for "cold spots".
Being interesed, knowing a little bit about thermography (L II), I did some tests. I saw things which I could not explain. Who knows something about thermography and trees.
Re:Detection of diseased trees and plants Gary Orlove 1/24/2005
More links that may be of interest

Use of infrared thermography for monitoring stomatal closure in the field: application to grapevine

Visualization of freezing progression in turfgrasses using infrared video thermography.

Thermography for Estimating Near-Surface Soil Moisture under Developing Crop Canopies

Robotised time-lapse imaging to assess in-planta uptake of phenylurea herbicides and their microbial degradation

Thermography studies of the spatial and temporal variability in stomatal conductance of Avena leaves during stable and oscillatory transpiration

Freezing of Barley Studied by Infrared Video Thermography

Presymptomatic visualization of
plant–virus interactions by thermography

Isolation of stomatal mutants by infrared thermography

Gary Orlove
Infrared Training Center
Re:Detection of diseased trees and plants Dr vanlio 11/19/2005
i am interested too in measuring trees. Have you found any interpretation?
you speak of Mr catena, why haven't you contacted him?
can i have his address?
Re:Detection of diseased trees and plants Top Gun 4/24/2006
Back in the mid 1990s while working with ISI cameras and Monroe thermography, Mr. Monroe mentioned infrared detection of "prewilt" in citrus trees. He said that once a citrus tree shows signs of wilting due to lack of water, it invariably dies. Trees with plenty of water showed a lower foliage temperature and those that were in the "prewilt" stage were warmer.

Just passing this on- I havn't researched it and took the gentleman at his word. --Steve Moore
Re:Detection of diseased trees and plants tripod 8/23/2006
Could someone tell me if a take a sample of wood from a supposedly diseased tree is there anywhere this could be taken to be analyzed to see if ndeed this tree is diseased?
Re:Detection of diseased trees and plants gioga2008 2/28/2012
You can find interesting information in my website (theory and some practice), where you can download some papers in English and Franch

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