Insect Pest Control
One sign of a healthy garden is one that is free of pests and pest damage. The best way to keep a garden free of pests is to keep your garden in a condition that doesn't allow pests to thrive and stay on top of pest populations year-round. By keeping plants healthy, you give them the best chance of overcoming any pest problems your garden may incur.
There are three types of bugs in every garden: bugs that do not harm your plants, bugs that harm your plants, and bugs that kill the bugs that harm your plants. First we will discuss the insects that cause the most damage to many lawns and gardens. Then we will discuss control methods, including the use of predator insects, to keep your garden healthy.
The insects that invade and damage your lawn or garden may be very visible or nearly invisible. The best way to protect your lawn and garden is to inspect it regularly for signs of damage or a growing pest population. Depending on the insect, you might notice the insects first or you might notice their damage. Look at the leaves on each plant type in your garden, both on top and underneath. Many insects lay eggs or eat from underneath the leaves, so the damage might not be apparent on top of the leaves. Look for leaves that are yellow, wilting, puckering, discolored or malformed. Use a magnifying glass to look for tiny insects like mites and aphids. Or, hold a white piece of paper under a leaf and shake the leaf. Inspect the paper for tiny insects.
When you do find insects that are causing damage, identify the insect. Using the wrong treatment can make an insect problem worse by disrupting the natural balance of your garden. Below is a list of some of the most common garden pests.
The best way to control the population of damaging insects once they have arrived is to use mechanical methods and not allow the population to get out of control. Remember that just because you see a few insects does not mean that you need to immediately take aggressive action. Many pest problems will disappear when the weather changes or when a predator species tracks down the pests. If you are seeing a new pest for the first time, watch it for a few days to make sure it needs to be controlled and that no predator bugs come along to kill it off on their own.
Mechanical methods include trapping, removing, and blocking the insects. One of the best methods for trapping crawling insects is to use a sunken container filled with soapy water and sugar to attract insects and then trap them in the water. You can also use sticky paper to trap flying or jumping bugs. Most traps are not effective at keeping large numbers of insects at bay, so other methods will be necessary once you start finding more insects in your traps. Removing insects can be done by hand or with blasts from a garden hose. Large pests like the Japanese beetle can be removed by hand and drowned in a container of soapy water. Smaller insects like spider mites can be blasted off plants with a hose. When manually removing insects, you will likely need to perform the task at least once a day until the population has been reduced to your satisfaction. Blocking insects often means placing netting over your plants to keep bugs away from the leaves. For small plants susceptible to attack by grubs or cutworms, placing a cardboard ring from paper towel or toilet paper around the seedling is often an easy and effective solution.
TIP: Manually remove Japanese beetles from your garden during the day when they come out to feed. Fill a milk jug one-third full with a soap and water solution (dish soap works great) and deposit beetles into the jug as you work. You'll have an easy-to-hold container from which it is nearly impossible for the beetles to escape. When you finish, put the cap on the jug and wait 24 hours to empty it.
Biological methods of pest control include predator insects, pathogens or parasites. Predators eat the pest, pathogens cause disease that disables the bug, and parasites live off the bug and eventually kill it.
One of the most common predators is the lady beetle. Lady beetles feed on insect eggs, aphids and larvae, making them a very effective garden predator. Other common predators are spiders, assassin bugs, green lacewings, predatory ground beetles, and predatory mites.
The most common pathogen used to treat garden pests is B.t., or Bacillus thuringiensis, though it is only effective on caterpillars. Make sure you match your caterpillar to the correct strain of B.t. or the treatment will have no effect. Though the pathogen results in fatal digestive system interference in caterpillars, there are no known negative effects to animals or humans.
Common parasites are insects that latch onto another insect as eggs, attack the insect in the larval stage, and kill it before they reach adulthood. One example is the trichogamma wasp, a tiny wasp you might notice flying around your garden which is too small to sting a human but will latch its eggs onto the eggs of garden pests and eventually kill the pest.
Make sure you research and properly identify the pest before you introduce any of these biological methods. You should also check with your local cooperative extension to make sure releasing predator insects is not prohibited in your area. While they will not damage your lawn or garden to any noticeable degree, some predators will have a negative impact on other aspects of certain environments, such as bee and mollusk populations.
If using mechanical or biological methods to control insect populations fails, chemical control methods may be your only option. Chemical products can be organic or synthetic. Organic products will generally break down more quickly and might not be as effective. Synthetic products break down more slowly and usually need to be applied carefully to prevent damaging the plants. Whether you apply an organic or synthetic product, make sure it is for use on the pest you are attempting to control, or you could make the problem worse. Always follow directions carefully and use protective clothing and eyewear.
Always remember, a healthy garden is your first and best defense against insect pests. Healthy plants will be able to withstand most minor infestations without permanent damage while nature takes its course to remove the pests over time.