Test, Don't Guess. How to submit plant and insect samples for diagnosis.
Plant disease samples
Provide a good amount of root, crown, and leaf material–send the whole plant, if possible. Dig the plants; do not yank them out of the ground. Select specimens that exhibit early symptoms–a completely dead section may no longer contain the source of the problem.
Turf: The specimen should be at least 4" in diameter and as deep as the roots. Collect from the border between healthy and diseased turf.
Fruit, tubers, vegetables: Select specimens that show early stages of decay. Include leaves and stem, if possible.
For plant identification: Many Cornell Cooperative Extension officesprovide superb plant identification. Specimens that defy identification may be sent to Cornell. Try to pick plants that show both older and newer leaves and flowers.
For nematode identification: During the active growing season, use a standard 1" soil auger (tube) to collect six soil core samples at a depth of 4" below the surface of the soil. Collect randomly from an area of approximately one acre. (If sampling from an individual specimen such as a tree, collect the soil from within the dripline of the tree’s canopy.)
Mix the samples thoroughly in a clean container, then transfer about a pint of soil to a plastic bag. Be gentle; don’t overmix the soil. Some nematodes can be injured easily. Keep the sample cool until it’s shipped.
Wrapping and packaging plants
Whole plant in a "live" state: Wrap the roots and lower shoots in wet paper towels, then enclose in a plastic bag. If sending a potted plant, cover the pot with a plastic bag. You may wish to enclose the upper foliage in a plastic bag that’s had holes punched in it. Do not water the plant before shipping.
Fruits, tubers, vegetables: Wrap in dry paper towels or newspaper. Wrap again with aluminum foil, wax paper, or plastic that’s had holes punched in it.
To dry and press a specimen: Collect when its foliage is dry. Shake most of the soil out of the roots. Arrange the plant on paper; press down gently to flatten it. Cover with paper, then sandwich this between a few pieces of cardboard or within a press. Lay a weight on top. Store in a warm, dry area until the plant is dry.
On the submission form, describe what’s happening over the whole landscape (for example, are all trees affected, or only one species?), and the effects on an individual plant ("abnormal swelling in the main stem"). Tell us about your cultural practices: watering, mowing, fertilizing, and any chemical applications.
Include photographs with your submission– if it’s not too much trouble, and won’t delay shipping. Pictures can be extremely helpful, but most analyses are done without them. Take several views: the overall landscape, a close-up of a single plant, and a close-up of the symptoms of the problem.
Plant Disease Diagnostic Clinic
Department of Plant Pathology
334 Plant Science Bldg.
Ithaca, NY 14853-4203
Phone: (607) 255-7850
Fax: (607) 255-4471