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Better Pictures for Diagnosis

August 13, 2003

Pictures are worth more than a thousand words in diagnosing a plant problem. Taken incorrectly, however, the pictures may be nearly useless. Images (photos or digital) are a welcome addition to samples sent to the clinic. Those who have used the Extension digital diagnosis system know that the image submitted is the main source of information. Here are a few tips from a diagnosticianís point of view on how to take better pictures for diagnosis.

Focus and lighting are the two most frequent problems. Take the time to get the picture in focus. That seems rudimentary, but we receive many blurred images. Hold the camera still and squeeze the shutter-release button rather than moving the whole camera as you push the button to shoot. Always work with the sun or major source of light behind you. With the light source behind the subject, the image is dark, looks like a shadow, and masks details needed for diagnosis.

How do you know what pictures to take if you donít know the cause? Try to use the pictures to show the diagnostician the complete problem. We then try to determine the cause. Three good pictures are usually enough. Pictures should show the overall pattern in the landscape, the pattern on one plant, and a close-up of the symptoms.

Stand back and get a view of the entire lawn or garden. This shows the condition of nearby plants, overall damage, possible site problems, and many features you might not think to mention or describe.

Next, move closer and photograph the entire plant from the soil line to the top of the plant. For trees, it is important to see how the trunk enters the soil, tree shape and branching pattern, and injury pattern. Pull back foliage from around the plant base and take a picture of the base as it enters the soil.

Finally, take an image of the insects, spots, blights, lesions, odd coloring, or whatever particular problem you see. In a few cases, it helps to put the insect or lesion under a microscope to see insect parts or fruiting bodies of fungi. Extension offices are set up to take digital images through dissecting microscopes. Often, however, it is not necessary to show that much detail. Although pictures are not necessary to obtain a diagnosis, they certain add to accuracy and convey the extent of the problem.

Author: Nancy Pataky


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