Samples should be sent by overnight delivery for virus assays. Carefully dig up and submit entire plant if possible. Place soil and roots in one plastic bag, then place another bag over the top of the plant. In the case of large trees and shrubs, submit a branch or part of the plant showing typical symptoms in a plastic bag. Various sized roots, specifically fine fibrous ones, should be submitted with soil in a plastic bag for fungal isolations.
Roots showing healthy and damaged areas are preferred.
Severely rotted roots alone may be overcome with secondary invaders, which can mask the primary cause of the problem. Submit container-grown plants with a plastic bag over the top. Submit one quart of soil in a plastic bag for nematode assay. A full soil box full is needed to test for soluble salts, nutrient imbalances, and unfavorable pH values. If a soiless medium is involved, one quart of this medium is required.