Types of Plant Problems
Are you a plant-watcher? It may sound boring, but it can be interesting — especially when something begins to harm your plants. If you pay attention to how your plants are growing on a regular basis, you will notice plant problems as they begin to develop. You will also have a better idea of how the plant is supposed to look when it is healthy and doesn’t have any problems.
Insects come in three major plant-damaging groups based on the way they eat. There are the chewers, the suckers and the borers.
Chewing insects damage plants by eating leaves or stems. The leaves can be eaten whole, or holes can be chewed in the leaves. Some eat the leaves and leave all the veins. The chewers, commonly including caterpillars or beetles, cause the most visible damage and are often very visible themselves. They are usually easy to get rid of and can be stomped on or sprayed with soap or other insecticides.
The sucking insects leave small brown dots on leaves and stems. They suck the sap out of the plant and leave the droppings of sticky sap on lower areas, including cars or whatever else is under the plant. The sap may turn black, with sooty mold growing on it. Aphids, scale insects, leafhoppers, plant bugs and whiteflies are the most common of these pests. Besides the usual pesticides, systemic pesticides — which are soaked into the plant — are very effective.
Borers are the hardest group to identify and treat. They can bore into an individual leaf or kill an entire tree. They make an entrance hole and often leave sawdust at the entrance so water and predators do not follow. Systemic insecticides applied at the proper time are a good control.
Fungal diseases are the most common ones. Use a magnifying glass to see the fine, thread-like growths on the surface of a leaf. Fungal growth inside a leaf may produce pimple-like structures on the leaf surface, where spores are produced. Some plants naturally produce white powder on the leaves or stem. Powdery mildew also forms a white powder but only during certain seasons.
Leaves infected by fungus will often have black or brown spots, or just turn yellow and fall off. Sometimes whole branches wilt and die. Fungicides applied at the proper time are effective but, oftentimes, so is creating more sunlight and air circulation by doing some pruning. Reducing the water that sits on the leaves in the evening — when the water does not dry off quickly — will help to slow the spread of fungi.
Many bacterial diseases look like fungal diseases. Knowing the most common problems for a particular plant will help speed the diagnosis. Some bacterial diseases grow quickly and produce a wound on the plant that bleeds or oozes a stinky slime.
Once you begin to recognize insect- and disease-related problems, you will be quicker to notice when something does not fit the pattern. By the time most people notice a disease, there will be a dead area on the leaf or plant; next to it, a discolored, sick area; then a just-getting-infected area; and then outside of that, healthy tissue remains. This leaves a bull’s-eye pattern.
Environmental problems tend to affect the whole plant or even the whole landscape. If more than one species growing next to one another is affected in the same way, it is often an environmental or man-made problem. If the plants are of the same family, they can get the same diseases, but different families of plants usually get different problems. First, look for physical damage. Did a rabbit, deer or string trimmer nibble on the plant? Did something recently change in the area? Was there digging or spraying done? Was a tree that shaded the area cut down?
After you figure out what might be the cause, you must ask yourself how much harm it will do. Is the problem occurring at the beginning of the season when it will stunt the plant, or is it late in the season and will go away on its own?
Is the whole plant or only one part affected? Is the problem worth treating for only a few leaves or branches? Is the plant a major part of the landscape? Sometimes the problems are merely cosmetic and do no real harm to the plant. Sometimes the pest goes away after only a short time on the plant, and other times, it will take major effort to get rid of it. Starting early will help get rid of serious pests.
Plant-watching can be a fun activity if you stop to smell the roses, lilacs, lilies, honeysuckles and other many beautiful plants in the landscape.
Email questions to Jeff Rugg at [email protected] To find out more about Jeff Rugg and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com.