Natural ways to control persistent garden pests

Brian Hallett

Nothing can take the green out of a gardener’s thumb like an insect infestation. Despite cold winters, the north country is not without its garden pests. And, controlling common garden pests like aphids can really seem like a full-time job if you do not properly plan your garden. Not only do these tiny insects suck the fluids from plant leaves and stems, leaving behind honeydew, a sticky residue that attracts ants to feed on it, but aphids also promote the spread of plant disease. Aphids are tiny, rarely exceeding an eighth of an inch, and teardrop shaped with long, slender legs. Depending on the species, aphids can be green, brown, yellow, red or black, and they are often found congregating on the underside of leaves. Luckily, there are some basic, all-natural ways that you can prevent garden insect invasions so your sowing and reaping time doesn’t just become spraying and worrying time.

Not all bugs are pests. There are good bugs and there are bad bugs. In fact, there are plenty of wonderfully beneficial insects, like ladybugs. You can invite these natural exterminators into your garden and they will eat their weight in plant-damaging aphids. There’s probably no more efficient and eco-friendly way to keep aphids and other common garden pests out of your garden than to grow herbs, vegetables and plants that repel aphids. Not only do you get the delicious, beautiful end products, your productive plants do double duty by keeping their own garden beds pest-free. To encourage good bugs to linger, plant flowering plants or herbs that ladybugs prefer like cilantro, dill, fennel, cosmos, marigolds, geraniums or morning glory vine. Also, avoid commercial broad spectrum pesticides that eradicate all bugs, including beneficial ladybugs.

Possibly the easiest and most rewarding way to control garden pests and to deter infestation is to keep your garden healthy and clean. Underfed, poor soil and dehydrated, stressed plants are particularly vulnerable to hungry insects, so be sure to keep your garden soil fertilized and appropriately watered. Always water early in the morning or in the evening, from underneath the plants rather than over the top of them to keep the leaves from burning in the sun when water evaporates. Also, remove dead and dried plant parts and fallen leaves, as insect eggs and larvae can lurk in decaying matter.

It’s important to weed your garden. A steady supply of weeds is just another way to encourage garden pests to linger. Even if you keep your garden bed weed-free and clean, other, less attended parts of your yard can offer a steady source of feed via weeds. Aphids enjoy a common weed called pig weed. Pig weed is a summer annual in the north country that thrives in poor conditions. It propagates by seed. Be diligent about removing weeds from your yard because once your garden crops are ready, those hungry bugs will happily move on to reap all that you have sown.

Finally, if you can’t beat them, maybe it’s time to kill them and save your garden. Here are some all-natural, homemade solutions to help you knock those buggers out. First, hit them with the hose. Aphids tend to congregate under the leaves and on the stems of plants. A strong spray of water can drown many of them. Next, soap is an effective, all-purpose pesticide. Organic gardeners know the value of insecticidal soap. Made from plant material, it is safe to use in the garden and indoors. It acts by washing away the protective coating on an insect’s shell, causing dehydration and death. Insecticidal soaps will kill aphids while sparing beneficial insects. According to scientists at Cornell University, good coverage of the plant with the soap is essential, and you should spray your plants in the early morning or evening to avoid evaporation of the droplets on the leaves.

Insecticidal soap spray

1 Tablespoon Dr. Bronner’s Liquid Peppermint Pure-Castile Soap
1 quart water

Combine ingredients in a bucket, mix, then transfer to a spray bottle as needed.

Many gardeners are discovering how easy it is to make insecticidal soap that is safe to use on food and around family and pets. There are many recipes on the Internet for homemade insecticidal soaps. Dishwashing soap contains perfumes and dyes and, in a concentrated form, can harm plants. Whenever you see “homemade insecticidal soap recipes,” be careful not to burn your plants with dish soap. I recommend Dr. Bronner’s Liquid Peppermint Pure-Castile Soap diluted with water. You can literally brush your teeth with Dr. Bronner’s soap. I pick it up at my friend Kelly’s health food store in Adams Center, Green Thyme.

Soap has been used for centuries as an all-purpose pesticide. The key is to not use too much, or you’ll also kill the vegetation near the pests. If you follow the proportions of soap to water in the soap spray recipe, vegetation should be fine. Always test first. Spray a small amount to ensure plants are OK before making a full-scale application.

Good spray coverage is essential for good results. Spray it directly onto the insects when they are first spotted on buds, shoots, stems and the underside of leaves. Wet both sides of the leaves and growing points of the plants. Spray in the evening or early morning hours so the spray droplets do not dry out quickly. This may also kill more pests. The spray is safe to use on houseplants, vegetables, herbs and flowers. Insecticidal soap should be applied weekly for up to three weeks, and it can be used up to harvest day. In general, some crops and certain ornamentals are sensitive to burn caused by soaps. Multiple applications in a short period of time can increase plant damage. Water conditioning agents can also increase plant damage. If you use a water softener, use distilled water.

Prevention is the best control. Develop and maintain healthy crops by maintaining soil fertility, properly irrigating, choosing plants suited to the climate and the soil and removing small infestations and bagging or burning them before they grow worse.

Brian Hallett is an art teacher at South Jefferson Central School in Adams. His family owns Halletts’ Florist and Greenhouse in Adams, which celebrates 30 years in business this year.