Plant Talk |
CAUTION:The information and recommendations in this article are applicable to Harnett County, NC and may not apply in other areas.
HELP! MY PLANT IS SICK, 06/06/97
A typical call to my office might sound something like this. Caller: "I have a geranium that has gooey stuff and little green bugs all over the leaves." Me: "Take two soil samples and call me in the morning."
Actually, I strive to be more helpful than that, but plant problems can be difficult to solve. Unlike people, you cannot ask them where the pain is. So here are some tips on how to solve plant problems.
Plant problems usually fall into one of four categories: insects, diseases, nutritional problems, and injury.
Insect problems are often easy to identify. You can actually see the critter doing the damage. It is trickier when the insect has eaten its fill and flown on to the neighbor's yard, or when the insects are too small to see without a magnifying glass. And some insects like to bore into the stem or trunk where they can cause damage without being seen. So be sure to look on the underside of leaves, and for small holes in stems or trunks. Also keep in mind that some insects help us by eating pest insects. Be sure to identify it before trying to kill it.
Diseases can be a little harder to identify. They are usually caused by bacteria, fungi, or viruses. Typical signs might be a grey powdery coating on leaves (powdery mildew) or a black sooty substance (sooty mold). However, since most disease organisms are microscopic, you may only be seeing the symptoms (i.e. leaves falling off or plant wilting). Sometimes the disease organism is in the soil, which can only be determined by laboratory tests. Nutritional problems can often be confused with disease problems. This is why the words "soil sample" creep up so frequently in my column. It is the only way to be sure that the plant has the nutrients and soil environment it needs to be healthy.
Injury is the fourth category. Frost injury is usually fairly easy, since there will be visible effects immediately after the event. But other causes could be high winds, or disturbance to the root zone from construction activity or vehicle traffic.
I normally play 20 questions with callers ("Where was the plant on the night of the 27th?"). If I cannot determine the cause over the phone, I may request you to bring a sample to my office. As a North Carolina resident, you have at your disposal a laboratory staffed by highly trained professionals, whose sole job is to identify plant problems. If you bring me a sample, I will send it to the lab for you at no charge!
A good sample consists of several handfuls of foliage, from both healthy and damaged parts of the plant. I will also need at least one quart of soil, collected from 4 or 5 spots around the plant and to a depth of 6 inches. Try to include part of the fine root system in your sample. Or even better, for small plants simply bring the entire plant, including top, roots, and soil.
Another good strategy in solving plant problems is regular monitoring. This is a lesson we can learn from our cotton farmers. They scout the fields regularly looking for problems. When the problem is found and identified early, it is generally much easier to control. So scout your yard and garden regularly. Look under leaves, carry a magnifying glass, and see what you can find.
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