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From droughts to flooding and heat waves, the weather has been tough all across the country recently. Did you know that pests can significantly reduce your garden yield? According to the Connecticut State Agricultural Experiment Station, you could be dealing with several kinds of pests that drastically impact your garden.
Some are perennial pests, like plum curculio that attack peaches or striped cucumber beetles that eat up your cucumber plants. Other pests are influenced by the weather, including aphids, mites and scale insects. Finally, you have “boom and bust” type pests that come in waves of infestation, such as tent caterpillars and spongy moths (colloquially misnomered as the gypsy moth). Here is how to deal with pest pressure of each type in your garden, without using chemical pesticides.
Related: Save water on your home garden with these helpful tips
Perennial pest control for your organic garden
Plant pairings for organic pest control
Ideally, your first option for dealing with perennial pests is learning good plant pairings that naturally keep pests at bay. For example, marigolds can be planted around your garden in open spots at the ends of plant rows to keep away pests. From squash bugs and tomato worms to mosquitos and cabbage worms, marigolds are some of the most popular plants for natural organic gardening to keep pests at bay.
Neem for controlling white flies and pest infestation
If you have whiteflies, you know how hard it can be to get rid of this perennial pest. Most organic farms will remove diseased or infested plants to control pest pressure. But if it’s really getting to you and white flies are spreading from your beans to your potatoes and destroying your crop entirely, break out the neem oil. This oil is relatively harmless to humans and other mammals, but it does dessicate some insects on contact.
The only caution with neem is that you want to spray it diluted in water on your affected plants’ leaves top and bottom at a time of day when bees and butterflies aren’t active, such as a cloudy evening, and give them an hour to dry. Then the neem becomes harmless again, but it will kill off the pests attacking your plants.
Diotomaceous earth for organic pest control in the soil
Grubs and slugs can be one more devastating perennial pest in your organic garden. If you want to handle them the natural way, use some diatomaceous earth. According to Gardener’s Path, this organic pesticide has been used for decades to handle pests in the ground by cutting up the respiratory systems of bugs that inhale it or drying mucous membranes of breathing holes and lungs in various insects.
Diatomaceous earth (DE) is made of ground-up, prehistoric diatomic fossils, so these tiny oceanic skeletal pieces aren’t harmful for your garden, but beware any bugs that come in contact. It is effective on slugs, beetles, worms, fleas, mites and most spiders or insects, but doesn’t harm larger creatures. DE is safe around children, pets and adults, as long as none of them have asthma, as breathing in DE can be irritating to the lungs.
Weather-related garden pest infestations
In many areas of the U.S. and around the world, it has been an unusually hot year, with long stretches of drought followed by soaking rains. This can raise pest pressure as well as weed pressure, because only native hardy bugs and plants tend to do well in these more extreme conditions.
Identifying pests in your garden
To handle a weather-related pest invasion, first download an app that can help you identify the pest, or send a photo to your local agriculture extension office (usually associated with your local university) or post on a farmers group on social media to ask for identification help. One other way to identify garden pests is to pay attention to what plant it was found on and what season or behavior might be notable.
For example, if you see a stripy beetle only on your cucumber plants, that’s probably a cucumber beetle, while a spotted beetle on your potatoes is probably a potato bug. It’s not always that simple, but this will give you a head start figuring out where to start with pest control efforts.
Plan ahead to treat predictable garden pests
Once you know what pest you’re dealing with, you can also plan on treating your garden ahead of time for repeat pests. Maybe your spring has gotten suddenly hot and you can’t grow greens and cucumbers anymore. In that case, protect your vulnerable plants with extra screening, such as a cage around your broccoli to keep cabbage worms from laying eggs on the plants, and plan ahead to treat plum curculio in the right season before these worms eat through all your peaches yet again.
Screening and manual pest control methods
Can’t figure out what bug you’re dealing with? Try non-chemical pesticides in affected areas first, or screen off vulnerable plants that take the most pest pressure in your garden (you’ll have a sense for this after just a couple years of gardening).
Then, if that doesn’t work, make sure that you have enough air flow and space between your plants to prevent pest spread, and try to keep up with removing pests manually from your plants every time you weed. This can be ineffective if you wait too long, so if you really want to keep your garden organic, pay attention early and often to stay ahead of manual pest control.
Deterring insects is the best method
You might be surprised how much easier it is to learn about keeping pests out of your garden with deterrents like the marigolds mentioned earlier. In some climates, certain plants just don’t stand a chance against large numbers of grasshoppers that eat them to the ground. You might have to shape your garden around what can compete with weeds and pests in your area.
We planted some beans as a cover crop early in our gardening adventures, but planting them as cover meant they were too close together and white flies soon took over the patch and spread to our potatoes, eating all the leaves. We had to harvest our small potatoes early and spray with neem. But it was too late, and the next year the white flies were established, so we just gave up on the potatoes after two years and only plant bush beans now in limited numbers.
Fragrant astringent plants can often deter pests, too. Basil, mums, garlic, rosemary, lemongrass and petunias can all help keep pests away. If you don’t want to quit on potatoes like we did, try planting lavender, peppermint, sage, thyme, marigolds, fragrant flowers like peonies and other strongly scented flowers and herbs, which are surprisingly unappealing to many insects and even deer.
Our deer only eat plants by the house when they’re super hungry in the late fall, so a deer fence around the vegetable garden is enough deterrent. We still have ground hogs and rabbits tunneling into the garden, however, plus voles and birds eating most of the strawberries and raspberries. Sometimes you just have to plant what the pests don’t want to eat and call it a win.
Keep your plants strong to resist pest invasions
Finally, the best way to avoid pest invasions is to keep your plants healthy. Strong plants are less likely to be attacked than plants that have a weakness, such as damaged bark or a virus or mold that degrades a plant’s health and defenses. Follow the proper instructions on planting, pruning, watering, weeding, and spacing of each plant variety in your garden to avoid problems.
For example, we split our garden into watering zones but accidentally put some field flowers next to the peonies. Next thing we knew, the peony leaves were looking a bit moldy while the other thirsty plants thrived. Now that we have test our garden location for a few years, we have shuffled around the plants so they can stay healthy in proper plant pairings. This can also extend to how much light a plant needs. We never plant something that needs full sun behind a trellis of beans as it won’t get the right sun or water.
Avoid over fertilizing, too. Some plants like lilac bushes only flower when you don’t fertilize them, believe it or not. These types of plants will only grow larger and greener in the presence of too much nitrogen fertilizer. Know your plants before you put them in the garden to avoid problems where improper plant care causes pest or blooming problems.
One other option is to run your garden as an organic garden, but consider supplementing with GMO or disease-resistant plant varieties for types of plants you struggle to grow in your area. This could give you a leg up on pest pressure. Just make sure the plant isn’t invasive, or you’ll end up with it taking over the garden (looking at you both, mountain mint and yarrow).
You don’t want a sterile garden, don’t get me wrong. Mulch the plants that need to retain more water, and don’t worry if some mold shows up in the wood chips or soil. That is probably just mycelium, which helps plant roots exchange minerals under the soil. It’s when the stems or leaves look spotty or fuzzy, the leaves turn brown or get holes, or you see a large number of insects on your plants that you want to pay attention. Ideally, you would want to catch it sooner than that, but we all have our lives to live. If you do run into a pest problem, go through the options here or look up organic pesticides for more options.
Occasionally, you might have to remove a plant manually to avoid treating it with heavy chemicals, and that is unfortunate. It’s up to you to find the best balance for your plants and your land. Another option is to rotate your crops year to year so that larvae infesting the soil won’t find the plant they were previously feeding on. This works especially well with brassicas. By rotating your garden, you also assure that your plants are not pulling specific minerals out of the soil in one spot every year, and have a better chance of keeping your garden healthy and pest-resistant.
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