Here’s a good article on ridding your garden of bugs by Deb Wiley and Viveka Neveln for Better Homes and Gardens.
Some insects and other small pests can cause big problems when they attack your plants. Here’s the best approach for dealing with them.
When you see bugs on your plants, it’s tempting to go with a “squish/spray first, ask questions later” response. But insects can be our friends or our enemies in the garden, so it’s important first to figure out what you’re dealing with before acting. Are the bugs actually eating or otherwise harming your plants? If it turns out that you do have “bad” bugs you want to get rid of, the best method for helping you figure out what to do is called Integrated Pest Management (IPM). IPM relies on cultural, physical, biological, and chemical tools, used in a way that targets the least toxic options necessary to do the job. Here’s how to put this approach to work for you.
How to Get Rid of Bugs in Your Garden
You can use IPM to eliminate bugs on any of your flowering plants, trees, shrubs, and vegetables. Just follow these steps with each type of garden bug you encounter, going in order until you reach the control level effective for dealing with the problem.
1. Decide on Acceptable Pest Levels
What is the acceptable level of aphids or Japanese beetles in your garden, for example? Some people cannot accept any, while others tolerate a small number of them because they’ll do little overall damage. A hefty infestation that’s clearly causing a plant to decline may warrant action. Still, if the plant seems unaffected other than cosmetic damage, some gardeners prefer to let nature run its course.
2. Practice Prevention
Crop rotation and attracting beneficial insects or other predators are a couple of cultural control strategies (i.e., how and what you grow) that can help minimize pest problems. If you have an invasion of cabbage loopers (small green caterpillars), for instance, you may want to avoid growing plants such as broccoli, cabbage, cauliflower, and kale for a season to starve out the looper population. And to keep grasshoppers at bay, plant marigolds, calendula, or sunflowers nearby to attract robber flies, which attack grasshoppers.
3. Keep a Close Eye on Pests
Scout your garden at least once a week. In addition to looking for generalists that commonly pop up in gardens, such as aphids and Japanese beetles, watch out for more specialized pests you know tend to show up every year, such as cucumber beetles in your vegetable garden or sawflies on your roses. The sooner you catch the problem, the easier it will be to nip in the bud.
4. Get Physical
For smaller, soft-bodied pests such as aphids, a strong blast of water from your garden hose can get rid of the problem pretty quickly. If you find larger pests such as Japanese beetles or tomato hornworms, knock them off your plants into a bucket of soapy water. (Wear gloves to minimize the “ick” factor if you’re squeamish.) For some pests that create a localized problem, such as webworms (caterpillars that make large nests that look like webs in the leaves of trees and shrubs), you can cut away the branches where the infestation is to solve the problem.
5. Wage Biological Warfare
Biological controls can take a variety of forms, but in general, any living creature that has a lethal effect on pests is fair game. Sawflies, for example, can be treated with spinosad, a natural chemical made by soil bacteria that is toxic to insects but not to people or pets. Similarly, Japanese beetle larvae in your lawn can be controlled with milky spore, which is a natural fungus that targets the grubs. You can also use “good bug” predators against some insects, such as ladybugs and lacewings, to gobble up aphids.
6. Apply Chemical Controls
When nothing else seems to be working, and you want to get rid of bugs on your plants, you can try a pesticide. There’s a large variety of products to choose from, some of which are organic (made from natural sources like neem) and some of which contain synthetic chemicals. Some are broad-spectrum, meaning they will kill just about any bug, and some are selective and will only kill a certain kind of insect, such as caterpillars. No matter which kind you choose, check the label to make sure the pesticide is actually for treating the bug you want to control, and pay close attention to any warnings, such as hazards to pollinators, pets, and people.
Usually, a combination of control measures will give you the best results. For example, you can get rid of squash bugs by protecting plants with a physical barrier like floating row covers, picking the insects off by hand, and planting marigold, calendula, sunflower, daisy, alyssum, or dill to attract beneficial insect predators. Finally, remember that most bugs you see in your garden will not do a huge amount of damage, so tolerating them is often the easiest course of action.