How do I take samples of plants?

How do I take samples of plants?

At this point in the diagnostic process, you probably have a tentative diagnosis of the problem. You are now focusing on confirming your suspicions. Each type of plant problem can require special techniques to get the best sample back to colleagues or to a diagnostic laboratory. Following are a few hints adapted from Ohio State University Extension bulletins:

Obviously, many times you can only sample a small portion of a plant, but when large numbers of small plants are affected, collect entire plants, including roots. If 500 rhododendrons are going down, do not just send a leaf or two. Dig plants to keep roots intact rather than simply pulling the material out of the ground. Remove excess soil by gently shaking or washing with water. Do not wet leaves or stems. Wrap roots so clinging soil won’t be loose in the packaging. Do not ship wet plants; let them air-dry first.
If only a portion of a plant is sampled, include the part showing symptoms. Also, when possible, collect about a pint of roots, soil and fine rootlets.
When only localized parts of a plant are affected (leaf spots, stem cankers), ship several examples of the affected parts. Stem and branch sections should include a short section of healthy tissue so the transition area between healthy and diseased tissue is included. For example, if collecting a sample to check for Verticillium wilt disease, select 1-inch diameter stem sections about 6 inches long, ideally from the area where the stem transitions between healthy and diseased tissue, rather than collecting dead stems.
If shipping, press non-woody plants or leaves on small twig between paper and put them between pieces of stiff cardboard, then place in a padded envelope. For succulent plants, samples packed in airtight plastic often decay before arriving in a lab. Place the leaves of such specimens between paper towels before packing. Use strong containers, filling spaces with shredded paper or other materials to cushion the sample in transit. Use rapid mail delivery for best results.