Dutch Elm Disease Sampling Procedures

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Sampling instructions | Incorrect sampling | Forwarding specimens for diagnosis | DED sample submission form

Sampling Instructions

1. Sterilize your pruning tools with methyl hydrate (gas line antifreeze), alcohol or 1% bleach. The use of bleach can rust the pruning equipment.

2. Select the branch in the elm tree that is showing the typical DED symptoms of leaf wilt or browning. This may require the use of a pole pruner.

3. Check this branch for brown staining in the cambium under the bark, a symptom of DED. If staining is not found, try another branch on which the leaf symptoms appear. Some degree of straining must be present in order to warrant sampling.

4. When staining is found, select a portion of the branch measuring 1-2 cm (up to 1 inch) in diameter. Cut 5 or 6 pieces about 15 cm (6 inches) in length, from a part of this branch. Do not submit pieces from which the bark has been peeled. Samples must have bark intact.

5. Roll each piece of branch individually in wax paper, making sure that the wax paper surrounds the entire piece as you insert the next piece. After samples are rolled, tuck over ends. The sample should be tightly rolled and placed in a paper bag. The bag is then rolled tightly and taped shut to maintain proper humidity. (Do not place branches in a sealed plastic bag as it promotes molding).

6. Fill out a "DED Sample Submission Form" with your assigned code number, your name, complete location or street address, phone number and date sampled. Include one copy with the sample which will go to the lab.

7. Include any information about the tree or growing conditions under comments on the submission form that would be helpful in identifying the problem.

8. Ensure that the sample includes the same code number as on the submission form. Mark this number on the bag with a felt marker.

9. All samples should be kept in a cool place until reaching the lab to prevent deterioration. Send the sample by courier early in the week to:
Dr. Stephen Strelkov
Ag., Food and Nutritional Science
University of Alberta
410 Ag/For. Building
Edmonton, AB T6G 2P5

10. Tag the tree to identify it as being tested. Make sure that the same code number is on the tree, sample and the "DED Sample Submission Form".

11. Disinfect the pruner head, secateurs and knife before taking the next sample. (This will prevent the possible spread from an infected tree to an uninfected tree).

Incorrect Sampling

Collectors have sampled:

very small twigs that are impossible to peel or culture.
twigs or branches without the brown streaks on the cambium.
dead branches in the crown "just to be sure".

Samples have been:

allowed to dry out before or during shipment over hot long weekends.
Solution: Refrigerate for the weekend and ship Monday.
allowed to accumulate for a week or more before shipping.
Solution: Ship daily.
shipped in a plastic bag or bags.
Solution: Re sample and place in paper bag.
shipped without proper documentation (i.e. without precise locations).

These samples are all a waste of laboratory time. Re sampling is the only course of action. In Alberta, the best sampling time is from the onset of symptoms in July to the end of August.

Forwarding Specimens for Diagnosis

Samples can be sent to the lab using any private courier. The address is on the submission form. Send specimens early in the week and avoid late-week submission as specimens may deteriorate in transit.

Go to the Alberta Dutch Elm Disease Prevention page for more information about prevention efforts in the province.

For information about STOPDED or Dutch elm disease contact Janet Feddes-Calpas at STOPDED Hotline: 1-877-837-ELMS (3567)

Dutch Elm Disease Sampling Procedures

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