High fever, nausea and headaches are all signs that a person is ill. If you pay attention to the signs, your landscape plants will let you know when they’re sick, too. Plants put out symptoms just like people do. You have to learn to be a landscape detective and pick up on the clues your plants are giving you.
Ask a few questions: When diagnosing problems in your home landscape, ask yourself a few questions. Is more than one type of plant involved? How many plants are affected? Is the damage on all the plants or is it localized? When did you first notice the problem? Have you recently applied a pesticide, herbicide or fertilizer?
Bag or Bottle ’em: If you find an insect on your plant and cannot identify it, save it in a bottle of alcohol and take it to your county Extension office to be identified. If your pest is a caterpillar, preserve the critter first. Blanch briefly in hot water before placing it in a vial of rubbing alcohol. This will better preserve the color. Plant leaf samples should be placed in a Ziploc bag and kept cool until the problem can be identified. Do not add water to the bag. Extra water will cause the sample to rot. Root samples should be placed in a separate bag to avoid cross contamination of soil borne diseases.
Ask first, spray later: If you think your plants have been infected by a plant disease, take a sample before you spray a fungicide. If you take a sample after you spray, you could actually mask the disease. If at all possible, wait until after you confirm the problem with your county Extension office. Most plant problems can be corrected without the use of pesticides. Plant diseases move through a landscape progressively. They will start in one area and gradually move to all the plants. You also need to look at where the plant is affected. Is it just one side, a few leaves or the entire plant? If it is the entire plant, the problem might be in the roots.
Don’t rule out human error: Yellow leaves can show that your plant needs more water, but plant leaves have also been known to turn yellow as a result of human error. A plant might be wilted because it needs water or because it has had too much water.
One agent got a call from a man who had a problem with all of the plants on one side of his house. They were all turning yellow. After talking to the homeowner, it was determined that the problem was caused by the bleach he had used to wash down his house. If the damage is distributed evenly across the landscape, the cause is likely environmental. Environmental factors that affect plants include cold or drought damage or, as in the case above, damage caused by humans.
Many times, being a detective can save you many dollars on useless chemicals.
Many of the chemicals available today are very specific. They affect only certain insects or diseases.
Be sure to read the label of any chemical you buy and use it correctly.