Tuesday, December 4, 2007

Troubleshooting for Horticultural Professionals II

Troubleshooting skills are critical for all horticulture professionals. This is a continuation of information on how to troubleshoot.

Troubleshooting (continued)

9) Recognize Patterns

Patterns are useful in determining if the problem is man-made, biological, chemical, environmental, or related to soil type. Patterns can be regular, circular or semi-circular, scattered, irregular, or involve whole sites.

10) Take adequate representative samples.

Comparison samples are a necessity to diagnose problems properly in many cases. Use site patterns, plant symptoms, site history, and cultural practices to determine what kind of samples you need and where to collect them. Label all samples and make notes about the samples. For comparison samples, collect normal and affected plants where possible.

If plant parts are sampled, choose those that show symptoms. If foliage is showing symptoms, consider whether a local or a larger whole branch or whole plant sample is needed. Consider if root samples will be needed. Dead plant parts may not be diagnostic; take samples from parts of the plants that are showing signs of problems but are not already dead.

If soil related problems are suspected, soil from both good and bad areas should be collected
If there are varying degrees of injury, take plants that represent all stages. Desiccated samples or rotten plant samples are worthless because secondary organisms may have colonized the sample and masked the real problem.

For soil compaction problems use a penetrometer or a soil probe to get an indication of possible problems. Subjectively compare the amount of pressure it takes to push the soil probe to the depth that compaction is suspected in the problem area and where no compaction is occurring. Dig some plants and observe the roots for restricted or abnormal growth. Look for polypropylene twine around the stem, pot bound roots, circling roots, shallow root systems, or roots that take an abrupt lateral turn.

For suspected salt damage problems, pull your soil sample from the plant rooting zone. For a possible temporary nutrient deficiency problem, take a root zone sample and a normal depth sample for comparison.

When sending samples to a diagnostic laboratory, follow recommended procedures for sampling, handling, and shipping provided by the lab.

11) Keep the samples in good condition.

Don't let plant samples dry out in hot conditions and don't let them begin to decay before you deliver them for evaluation. Adult insect should be handled with care so as not to damage them. Larvae and other soft-bodied insects should be kept in 70 percent alcohol. Water can be used instead of alcohol, if you can get the samples to an entomologist within a few days. Nematode and disease samples must be kept cool to keep the nematodes and other pathogens alive during transport to the laboratory. This also decreases the development of secondary organisms which can confuse diagnosis.

12) Invite expert opinions when you're not sure.

No one can know everything so use your expert contacts to fill in the details and confirm your diagnosis. Remember this is not a competition. Everyone must work cooperatively to solve client problems.

13) Diagnose the problem and then help your client correct it.

When trouble-shooting, a quick and accurate response is important. However, if laboratory tests are needed to confirm a diagnosis, wait for results before recommending corrective action. Throughout the investigative process, eliminate the minor factors to discover the primary cause. For example, although phosphorus deficiency symptoms can indicate a need for phosphorus fertilization, the deficiency can be caused by root pruning insects, poor drainage, low pH, low temperature, or chemical damage. To correct the deficiency effectively, determine which factor(s) is responsible before taking action. Applying the wrong treatment will cost your client money and may still not solve the problem. There will be times when it is not economically feasible to correct the problem, or it may be too late in the season to correct the problem economically. In these cases, use the opportunity to teach your client how to prevent the problem in the future. New problems do develop occasionally. New problems can often look very similar to old problems. Pay even closer attention to the clues that don't fit the old pattern. Keep an open mind! Remember, new problems may require basic research and a longer time to diagnose effectively.

14) Keep a record of everything.

Use a camera to take pictures. A visual record of affected plants, normal plants, and site patterns will be very useful. Keep written records of all the information you garner on the problem, all the expert contacts you make, special sampling you do, and other pertinent information. This documentation may be needed in court and will be invaluable in backing up your conclusions as well

From a UD Cooperative Extension Factsheet, originally written by Bob Mulrooney and Derby Walker for agricultural crop advisors and adapted for horticultural professionals by Gordon Johnson.

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