Sample Submission Procedures For Plant Disease Diagnosis

Selection of samples

  1. Select a sample that shows distinct symptoms.  If there are varying degrees of damage, include samples that are in varying stages of the problem.  Include a healthy plant or parts of plant if possible. Do not send us dead, dried samples - they can rarely be used for diagnosis.
  2. Send as much of the plant as possible. Depending on the problem, roots and shoots may both be necessary.  Often foliar symptoms are the result of a root problem.
  3. For roots: dig plants, do not pull them up.  Include as much of the root as you can dig out and leave adhering soil on the roots.
  4. For branches, shoots and leaves:  make sure several leaves or twigs are included that have symptoms.  Cut symptomatic sections of limbs or branches.
  5. Keep all samples refrigerated until ready to send (exceptions listed below).
     

Packaging of samples

  1. Put stems and leaves in a plastic bag, do not add water or wet paper towels.  Put roots with soil in a separate plastic bag, do not add water or wet paper towels.
  2. Put samples in a suitable box or mailing container so they will not be crushed.  Mail on Monday through Wednesday only so that samples do not sit over the weekend.
  3. Always include the name of the host plant, a description of the problem, dates of symptom development and sample collection, location, and the contact person for questions and/or results.
     

Special situations

Turf - use a cup cutter or knife to cut plugs or squares about 2 inches across and as deep as roots will hold soil.  Sample from the inside, edge, and outside of the problem area, and put these samples in separate bags marked accordingly.  Do not add wet paper towels or water. 

Fungal fruiting bodies such as conks or mushrooms - place as much of an intact structure as possible into a paper bag; do not use plastic for fresh fungal structures. 

Nematodes must be sampled from moist soil around the root.  Put a pint of moist soil (dig down to moisture if needed) in a plastic bag and seal.  Include small roots.  Keep cool but not cold. 
 
Sample Submittal Form

Extension Plant Pathology  | Department of Plant Pathology


December 12, 2006

http://ag.arizona.edu/PLP/plpext/sample/sample.htm