Recognizing Deciduous Tree and Recognizing Evergreen Diseases
At first glance, it may be difficult to determine if an evergreen is suffering from insect damage, disease, or environmental stress. But the second glance, followed by a closer study of the symptoms, can help you to make that determination.
Before you take that second glance you do need to know what kind of plant it is, and what a healthy specimen looks like. Is it a juniper, a pine, a spruce, or a yew? Do you know the species, or cultivar?
Now, take that second glance and answer this question: Where are the symptoms on the tree? At the top, or the bottom? On one side? Which direction does that side face? Are the symptoms on the branch tips, or the new growth? Or are they seen toward the interior of the tree (second year, or earlier growth? When did the symptoms first appear? Recently? Think back to what the tree or shrub looked like last year. Were their similar symptoms developing in mid-summer or fall?
Study the foliage and the area next to the damage. Do you see any discoloration, spotting, streaking or banding of the foliage? Of the stems? Do you see any galls on the foliage? Are there any fungi growing on branches or on the trunk? Is there evidence that insects have been or are feeding?
Last, but not least, take into account the possibility of a disease caused by the environment in which the plant lives. This means that some requirement of the plant is not satisfied, and, therefore, the plant is weakened. This could be lack of space for root growth, air or water pollutants, extremes of moisture, heat, cold, light, soil pH, and nutrients. To diagnose this type of decline, you must first rule out other diseases or insects, and then examine the site carefully. In addition, consider the possibility that the plant has suffered damage due to mechanical injury? Some diseases only occur when the plant is stressed or has been damaged by another cause.
Once you have carefully detailed the symptoms, compare your list with information from reliable sources about the plant in question. The Cooperative Extension Office has detailed information about the most prevalent diseases on plant material found in our area. If you are unable to determine exactly what is causing the problem, take a fresh branch sample to the County Extension Office, along with the list of symptoms that you observed. If necessary, the sample can be forwarded to the K-State diagnostic laboratory. Proper diagnosis is the key to adopting the proper control measures, and the details you provide from your on-site observations are invaluable.