Each garden season is filled with beautiful and tasty surprises accompanied by some challenges. A challenge gardeners face every year is managing insect pests while protecting pollinators. Fortunately, only a very small percentage of insects in our landscapes are pests. Others help pollinate plants, feed on or parasitize bad insects, or help break down plant debris.
Proper identification of the culprit that is damaging plants is the first step in managing problems. Often the most visible insect is not the one causing the damage. You can find a lot of useful information and images online. Look for websites hosted by your local university, extension service, or botanical garden. They often provide timely advice on pests in your area.
Once identified, you will need to decide if a check is necessary. Some insect damage is only cosmetic, which means that the health and longevity of the plant is not affected, but it looks bad. In these cases, the control is not for us the health of our plants. Consider tolerating damage and masking it with nearby plantings or garden artwork.
In other cases, the damage is done and the insect is no longer present. Revenge spray may help you feel better, but it does nothing to solve the problem. Make a note on next year’s schedule to monitor and manage the pest if you think control is really needed. Early detection of pest problems makes hand removal easy and may be all you need.
Often when we see the damage on our plants, control will not help. Many galls, unusual growths on plants, are caused by insect feeding. When we see the gall, either the insect is living safely inside the gall or it has escaped to complete another stage of its life. At this point the control will not work and in most cases this is a cosmetic issue and the control is not required.
Work with nature to help manage pest problems. By tolerating certain damage, you provide the food that attracts nature’s pest controllers to the garden. Watch for aphid-eating ladybugs and green lacewings, which eat hundreds of these pests every day. Invite songbirds into your landscape with seed and berry-producing plants and a source of clean, fresh water. Ninety-six percent of land birds feed their young insects. And then there are those non-stinging parasitic wasps that lay their eggs in other insects. When the eggs hatch, the young feed on the host. Avoid pesticides and provide water and shelter to attract and support insectivorous toads and frogs.
Ask for help from the young people in your life. Try the pluck, drop and stomp method. Teach young gardeners to identify problem insects, pick them by hand, drop them to the ground, and stomp on them. What a great way to teach kids about nature and help them burn off some of their excess energy.
Hand picking or knocking insects like Japanese beetles into a box of soapy water is a great way to manage small pest populations. A fellow horticulturist uses a small hand-held vacuum to capture Japanese beetles. Just be sure to empty the contents of the bug-filled vacuum into a can of soapy water before storing.
If you decide you need to give nature a helping hand to manage garden pests, look for more eco-friendly options. Floating cover barriers – fabrics that allow air, light and water to pass through – can prevent cabbage worms, onion maggots, Japanese beetles and some other insects from laying their eggs on their plants favourites. Cover the plants with the fabric when planting, anchor the edges and leave enough slack for the plants to grow. No construction is required.
Covering squash plants at planting until flowering begins can help reduce the risk of squash bugs and vine borers. Covering cucumbers at planting for up to ten days after flowering begins helps reduce the risk of cucumber beetles infecting these plants with the bacteria that causes wilt. Row covers also prevent birds from eating on seeds and seedlings.
Cover late plantings of susceptible plants as needed this season. Then mark on next year’s calendar to enlist this method of controlling these types of pests for your first planting next year.
Use the natural soil bacterium Bacillus thuringiensis (Bt) to protect plants from certain pests. Different strains of this bacterium control different insects. Bt kurstaki only kills true caterpillars. Using it on members of the cabbage family will not harm other butterflies since these plants only attract cabbage worms. Bt galleriae will control Japanese and other beetles.
Use a strong stream of water to dislodge mites and aphids. These pests suck plant sap and secrete a clear, sticky substance called honeydew. Intensive feeding can cause distorted growth, speckling, yellowing and browning of leaves.
If more control is needed, seek help from one of the organic contact insecticides like Summit Year-Round Spray Oil, a light horticultural oil. These products kill the insects they come in contact with but leave no residue on the plants that could harm beneficial insects that later visit the plants.
Whenever you use any product, even natural and organic, be sure to read and follow the directions on the label. This will ensure the best control and the least negative impact on beneficial insects and the environment.
Take some notes on the pests you encounter, the management strategies used, and the results. This will help you when you encounter problems in the future. With a minimum of time and a little creativity, you can keep your garden looking its best all season long.
Melinda Myers has written over 20 gardening books, including the Midwest Gardener’s Handbook, 2nd Edition and Small Space Gardening. She hosts The Great Courses “How to Grow Anything” DVD instant video series and the nationally broadcast television and radio show Melinda’s Garden Moment. Myers is a columnist and editor for Birds & Blooms magazine and her website is www.MelindaMyers.com.
An environmentally friendly way to manage small populations of Japanese beetles is to throw them in a box of soapy water.