Daniel Gill, Merrill, Thomas A.
By Dan Gill
LSU AgCenter Horticulturist
Insect problems increase when the weather warms up, and many gardeners still feel they should immediately get an insecticide and begin spraying when they see insects or some apparent insect damage in their gardens or landscape.
Just because you see an insect is not reason enough to spray, however. The insect you see may not be harmful or may not cause enough damage to warrant control. It may even be a beneficial insect that eats insect pests and helps keep them under control.
On the other hand, even when you are correct in thinking that you need to control the insects, it is very important to do it the right way.
The initial step in deciding whether to spray is to correctly identify the insect causing the damage. Once identified, find out if there is a way of controlling the pest without the use of insecticides. There are many techniques that can be used to control particular insects that do not involve the use of an insecticide.
Without proper identification of the pest, several things could go wrong. If the damage was caused by insects that have already come and gone, spraying won’t do any good.
For example, in spring you may notice that areas of your grass do not green up with the rest of the lawn. In many instances the damage was caused by chinch bugs the previous summer. Even though chinch bugs were responsible for the damage you see now, they are not active in spring, so treatment now would accomplish nothing.
In addition, indiscriminate spraying can kill beneficial predatory insects that are eating insects on your plants. This can actually cause insect problems to develop or become worse. You will have wasted time and effort and destroyed a friend instead of a pest.
If insecticides are needed, without proper identification you may spray the wrong material or use it the wrong way. Remember, no single insecticide will control all insects, and some can even make the problem worse. For instance, spider mites can become even more damaging if they are treated with the insecticide Sevin.
Also, insecticides for gardeners generally are short-lived to reduce the chance of environmental contamination from residues. Most insecticides break down in a matter of days or weeks after application and offer no protection after that. You can’t spray once in the spring and expect that your plants are protected indefinitely. Pest problems can, and often do, recur.
It is essential to read the label before purchasing and using an insecticide to be certain that it will control the pest you have. It also will tell you how much to use, how to mix and apply it and the safety precautions that must be taken, such as wearing protective clothing. Some pesticides have restrictions for use on certain plants and at certain temperatures that, if not followed, might cause the plants damage rather than helping them.
If you need to use an insecticide, find out which ones are the safest and least toxic. Check the label of the pesticide container for one of three words. "Caution" denotes the least toxic category of pesticides. "Warning" appears on the label of the next most toxic category. And "Danger" is on the label of the most-toxic category of pesticides. If several insecticides would be effective and appropriate to use, choose the one that is least toxic.
Also be sure to choose the right formulation. Different types of pests are controlled better with different types of insecticide formulations, such as baits, sprays or granules. Some insecticide formulations are more effective on a particular pest than others, and you need to choose the right one.
Another consideration is to always buy the smallest available container of a pesticide so you will use it up faster. Pesticides lose potency over time.
You also may want to consider the convenience of purchasing insecticides that are premixed and ready to use.
When using pesticides, the control method must be directed toward the pest. If the insect lives and feeds on the underside of the foliage, your spray should be directed there. If it lives on the trunk and branches, a light spray on the foliage will not be effective.
Only spray infested plants and nearby ones of the same kind. Do not spray everything in your landscape just because a few plants are infested.
When making applications of insecticides, kids and pets should stay out of the area.
You also need to read and carefully follow any safety precautions indicated on the label. Always wear rubber gloves when mixing and spraying insecticides. In addition, wear closed shoes, long pants and a long-sleeved shirt to minimize your contact with the spray. Goggles or some other form of eye protection also are recommended when using some insecticides.
Be wise in your use of insecticides. If you spray insecticides when they are not absolutely necessary, you needlessly introduce toxic substances into the environment.
Before you start spraying, be sure the insect is properly identified, and use the right pesticide at the right rate with the proper applicator. Always apply the insecticide according to the label directions and in a manner which will give you the safest and most effective control.
Get It Growing is a weekly feature on home lawn and garden topics prepared by experts in the LSU AgCenter. For more information on such topics, contact your parish LSU AgCenter Extension office or visit our Web site at www.lsuagcenter.com. A wide range of publications and a variety of other resources are available.