Are you looking for natural pest control options for the garden? Like many home gardeners, I started growing my own fruits and vegetables in part to avoid the toxic chemicals used on most commercial produce. After all, why put in all that time and effort to eat poison? It didn't make sense to me.
Just walking down the chemical isle in the hardware store, i.e., the “garden helper area” or whatever they call it, gives me a headache. Sometimes I purchase certain organic pest control products, but often you can get rid of garden pests with what you have on hand.
The old tip about the best defense being a good offense still stands, too. The healthier your plants, the less likely you are to have garden bugs doing serious damage. I also encourage beneficial insects and animals to help get rid of problem bugs. See Working with Nature – Shifting Paradigms, Building Soils Naturally: Innovative Methods for Organic Gardeners and Mycorrhizal Planet – Nurturing Fungi to Build Soil Fertility and Support Plant Health for more information on building a healthy garden ecosystem.
In this post we’ll cover how to get rid of 20 common garden pests – or at least minimize their damage so you can still get a harvest. Remember, a natural pesticide is still a pesticide. Always use pest control, even organic pest control, mindfully and selectively.
If you're looking for natural and organic pesticides, check out Homemade Bug Spray for the Garden – 3 Easy Recipes. These recipes work best on soft bodied insects.
#1 – Ants
Ants aerate the soil and clean up garden debris. Unless they are seriously disruptive, I leave them alone. If they are in a particularly bad spot, they can be encouraged to relocate by repeatedly disrupting the hive with boiling water or other disturbances. If they are farming aphids (see Aphids, below), getting rid of the aphids may get the ants to move on. For more detailed information on ant control, see “How to Get Rid of Ants Naturally”.
#2 – Aphids
Aphids suck the juices out of plants. If plants are stressed and weak, and aphid attack may do them in. Strong plants can withstand a fair amount of munching with little harm. Many beneficial insects munch on aphids, including lady beetle larva, small wasps, syrphid fly larva and lacewings.
For mild aphid attacks, try hosing the plant off with a strong jet of water. For more heavy infestation, mix up a batch of home pest control spray. (Get the recipes here.)
#3 – Asparagus beetles
These small orange and black beetles move into your asparagus patch and leave chew marks all over the spears. The larva head underground in fall to pupate and emerge the next spring, starting the cycle all over again.
Hand pick in early morning when they are cooler and less active. Encourage wild birds, frogs and snakes to visit your asparagus patch with perches, cover and water nearby. If you have chickens, ducks or other poultry, you may want to allow them into the patch for a short time in fall to clean up the larva. (Be careful with chickens. Too much digging will kill your asparagus crowns.)
#4 – Cabbage Worms and Cabbage Loopers
These small green worms are both moth larva. Cabbage worms mature into white moths, which are called cabbage butterflies because they are active during the day. Cabbage loopers mature into a dabbled brown moth. Both larvas are bright green, blending perfectly against the cabbage family plants they like to munch. Sometimes you spot the little dark green piles of worm poo before you spot the worms themselves. Their eggs are orange-yellow, and are often found on the undersides of leaves. Hand pick cabbage worms or loopers every couple of days to keep numbers in check.
If cabbage worms have gotten out of control, DE (diatomaceous earth) and Bt (bacillus thuringiensis) are two products available at garden centers that will slow them down. DE is made of finely ground rock containing the fossilized shells of diatoms. The grains are very sharp, and injure soft bodied critters. (Don't breath this. I'm sure it's not great for toads and frogs, either.)
To catch any cabbage worms you miss before they get to the table, check out “The Easiest Way to Get Worms Out of Broccoli“.
What is Bt?
Bt is a form of naturally occurring bacteria that effects the larva stage of insects, basically causing their stomachs to explode. Because of its overuse in genetically modified crops (the Bt gene is spliced into a crop such as corn so the entire plant becomes a pesticide – read more at Would You Feed Your Kids Pesticide Chips?), many insects are becoming resistant to these bacteria (there are multiple strains of Bt). As you can see, each product has some problems, which gets me back to hand-picking and encouraging healthy plants.
Growing cabbage family plants early or late in the season usually reduces insect pressure. These crops prefer cool temps. A light frost won’t harm them, but it will knock down the bug numbers.
Cabbage worms, like most insect pests, will show up in much greater numbers when your plants are stressed in any way. When I've accidentally planted them too close together so they are overcrowded, or dealt with drought or poor soil, my cabbage worm problems have been much worse.
Make sure cabbage family plants have ample room to grow (plant 2-3 feet on center) and give them plenty of nitrogen in the form of compost or rotten manure. It's hard to have soil that's too rich for these plants. When your soil is good and your plants are healthy, damage will be minimal and plants will recover easily. You can also fertilize with fish emulsion, weed tea or compost tea to give plants an extra boost of nutrition.
#5 – Colorado potato beetles
I vividly remember the first time my small suburban garden was attacked by potato beetles. One day the potato patch looked fine. A couple days later, the plants were chewed to lace. (This is another good reminder to check your garden daily if possible, to catch problems quickly.)
I didn’t know what Colorado potato beetle larva looked like, so I didn’t realize the plants were infested until the damage was severe
Here's an immature potato beetle.
Here's a mature potato beetle.
If you can catch these early before they become widespread, hand picking is easy. To hand pick garden bugs, I prep a large yogurt container or something similar with a couple inches of water in the bottom mixed with some soap to break the surface tension. Knock or drop the bugs in, and they don't come out. I don't recommend squashing mature potato beetles with your bare fingers, as they will bite and their shells are quite hard.
I have also used DE (diatomaceous earth) for potato beetles, but hand picking is my preferred tactic. The sharp edges of the DE are effective against soft bodied garden bugs, such as the potato beetle larva.
Don't Forget to Watch for Eggs!
Make sure to check on the underside of leaves for clusters of bright orange eggs, and smash them or scrape them into your soapy water. The boys used to make extra cash in the summer by acting as “bounty hunters” and earning a set amount per bug collected. You can also buy insecticidal soap specifically designed to be sprayed directly on bugs.
If you can get it, use straw much on your potatoes in addition to hilling. Barbara Pleasant notes in The Gardener’s Bug Book that straw reduces potato beetle damage by about half. Floating row covers can work for small patches – just make sure you don’t trap any beetles under the cover.
#6 – Corn Borers, European
If you’ve raised sweet corn in the garden, you’ve likely encountered corn borers. They’re about an inch long, and commonly found at the tip of the corn cob. Some corn varieties are genetically engineered to include Bt toxins to kill the borers, but they are starting to see resistance to these toxins. Other corn varieties have naturally tight openings to the husks or thicker husks, which helps to keep the borers out. Cold winters and cool wet starts to summers keep their numbers down, as do heavy rains, which knock off eggs before they hatch. Bt may be effective – if you can get it on the corn the borer is eating. Not easy when they are under the husk. We encourage birds and beneficial insects that hunt them, and trim off any corn borer damage we find at harvest.
#7 – Cucumber Beetles
Cucumbers beetles can do a fair amount of damage, plus they spread bacterial wilt. Bacterial wilt is a disease that gets in the soil. It can cause problems for years after the initial infestation. First off, work to maximize your soil fertility – better soil = plants that are less likely to attract pests and are more resistant when they attack.
Striped cucumber beetles have yellow and black stripes. They chew up the plants above-ground, and then lay eggs in the soil at the base of the plants. The larvae then chew up the roots. (Dirty devils…) Spotted cucumber beetles are slightly larger, and will also chew up your vine crops, but they like to lay their eggs near corn. Their larvae are known as corn rootworms.
At our old place, where we had poor, heavy clay soil, once the cucumber beetles showed up, and the bacterial wilt spread, I was not able to grow vine crops well again. Here, the cucumber beetles show up, but they don’t do much damage. Here I have a mixed clay/sand/loam and much more organic matter.
To control cucumber beetles, it’s best to get them early in the morning, when they are cooler and less active. They like to gather in blossoms, so I will gently shake a blossom into my container of soapy water, or use something like a popsicle stick to scoop them into the water. Sunflowers are great for attracting cucumber beetles – they love them! They gather on the sunflower heads and I shake them/brush them from the sunflower into the soapy water. You can eliminate large qualities of them very quickly.
For small plantings, you can protect them with floating row covers. Nonbitter cucumbers may attract fewer cucumber beetles than other varieties.
#8 – Cutworms
To me, it seems like adding insult to injury when a cutworm kills a plant by cutting it off at ground level, leaving the rest of the plant to die. When we first put in our garden, I had a lot more trouble with cutworms. Now it’s rare that we’ll lose a plant.
First off, cutworms are more numerous in areas recently converted from grass. Once you cultivate the soil for a few years and root them out as you see them, the populations go down. Spot a dingy grey grub-like caterpillar about an inch and a half long while digging? That’s probably a cutworm – which you may want to relocate to chicken food.
To protect young seedlings, stick a twig snugly against the stem of the young plant. The cutworm’s “grip of death” is interrupted by the stick. Another option is an empty can with the bottom cut out placed over the top of the seedling. Just make sure you don’t trap a cutworm inside the can. Natural predators of cutworms include braconid wasps, tachinid flies and ground beetles.
#9 – Earwigs
Earwigs are a little creepy to me because of their pincers. In the garden, they can be good and bad. They eat aphids, but they also chew on young seedlings.
To reduce earwig populations, try traps. Place rolled up newspapers or hollow bamboo sticks in the infested area. In the morning, dump all earwigs that took cover in the newspaper or bamboo into a bucket of soapy water.
#10 – Flea Beetles
If you end up with leaves that look like they've been sprayed with buckshot, and you see tiny, fast moving black bugs, odds are you have flea beetles.
In my garden, flea beetles like to go after early spring growth. Beans and peppers are often hit particularly hard, brassicas get some damage but not as much. Radish greens almost always show some damage.
My preferred organic pest control for flea beetles is coffee grounds. Coffee grounds can be applied after damage is spotted to give the plants a chance to recover (I've brought nearly dead plants back from the brink), but I've taken to applying the grounds when the plants are small to avoid damage in the first place. Around mid-winter I start saving up and ask friends to start saving their grounds as well.
#11 – Fruit Flies
There are many different species of fruit flies. They lay their eggs in fruit, and the maggots hatch and chew their way around inside. Tiny fruit flies take up semi-permanent residence in my kitchen once harvest time kicks in.
For natural pest control of fruit flies in the garden, try tangle traps, which catch the flies in sticky bait.
Inside, make sure to promptly use ripe fruit. Nothing triggers a fruit fly population explosion faster than a piece of rotting fruit hiding in the bottom of a container. (Some of you who are familiar with the site may have seen the large cardboard trays I use to hold produce. These make it easier to spot anything that’s starting to turn and process it immediately.)
My preferred homemade fruit fly trap option is homemade apple cider vinegar in an old candle holder. I put a drop of dish soap on the top of the vinegar to reduce surface tension, and cover the container with a piece of plastic wrap with a hole in it. Fruit flies go in, but they don’t come back out.
#12 – Grasshoppers
Thankfully here in northeast Wisconsin, we haven’t had a huge grasshopper invasion while I’ve been gardening. In many areas, they hit like a biblical plague, wiping out anything green.
Grasshoppers lay eggs in the soil, which hatch in the springtime, spread out and EAT ALMOST EVERYTHING.
Floating row covers can be used to protect small areas, but this is one garden pest that is best controlled permaculture style. What do I mean by that? Think of the grasshopper plague not as too many grasshoppers, but as a lack of things to eat them. Ducks and chickens will chow down on grasshoppers, and have a great time doing it. No poultry? Try and hunt the largest hoppers in August to keep them from laying eggs. Give them the soapy water treatment, use them for fish bait, or eat them like my friend, Paul.
#13 – Hornworms, Tomato Hornworms
These huge caterpillars can munch their way through a tomato plant at record speed. While these garden pests can do a ton of damage, the hornworms do pupate into beautiful hummingbirds moths.
Hand picking is the most reliable control method. Hornworms are also relished by poultry.
If you spot a hornworm with little white cocoons on its back, the hornworm is under attack from braconid wasps and will eventually die. Consider keeping it on a spare tomato plant, or in a jar with some tomato leaves to munch on, until the wasp babies have time to emerge.
Hornworms overwinter in the ground in 1-2 inch long dark brown pupae. Fall cultivation will help expose these to the elements and birds. Alternatively, put the chickens to work on garden clean up duty.
#14 – June Bugs, June Beetles
Come June, it’s time for the nighttime ritual thumping of these large beetles against window screens everywhere. The larvae of June bugs are large white grubs, with a preferred diet of grass roots. They’re a favorite food of skunks, which root them out of your lawn. Since corn is a grass, you’ll sometimes find the grubs chewing at your corn roots, too.
Adult June bugs are attracted to light traps (bug zappers). They ca also be hand picked from window screens and given the soap bucket treatment. For long term control, consider inoculating the soil with milky spore disease. Milky spore also kills Japanese beetle larvae.
#15 – Mealybugs
I’d never heard of these garden bugs until a reader requested help for their jasmine tree. The small white bugs are fond of tropical houseplants, citrus and other fruits.
For mealybug control in the garden, try a strong blast of water, followed by insecticidal soap.
#16 – Mice
Mice are tougher to get rid of than rabbits, as they are usually not deterred by herbs and scents like the rabbits are. In my garden, control is provided by my cats and local fox snakes. Unless you remove the mice or barricade your plants, damage will likely continue.
To keep mice away from a plant (or plants), you must use very fine mesh fencing – 1/4 inch or less is preferred. If a mouse can get its head through, the body will go through as well. I usually use fencing around individual plants such as blueberries.
Minimize brush piles or other easy cover near the garden. They also like to move into compost bins (especially in winter, when the heat keeps them nice and warm). Wood piles are another favorite hiding spot.
Traps and poisons are other options, but always be aware of other animals, pets or small children that may also encounter these items and plan accordingly. I don't put out mouse bait anymore since the cats moved in, as I wouldn't want my kitties eating a mouse that had eaten poison. The article The Best Ways to get Rid of Mice From Your Home and Garage provides more detailed information on mice and their habits and abilities and keeping them under control.
#17 – Rabbits
The first year I planted, the wild bunnies did a number on my freshly sown peas and other tender greens. I didn't want to fence everything, because it makes it more difficult to tend to, plus fences don't always keep bunnies out, so I had to come up with another solution.
I tried the spray on Liquid Fence products, and they worked – until it rained. They were also expensive. I tried cayenne pepper, which worked until the rain washed it off, but also burnt the plants where I had applied it a little too heavily.
My best solution for protecting my plants from rabbits is to mulch them heavily with strongly scented herbs. I've got volunteer catnip and lemon balm all over the place, which the bunnies don't bother at all. I cut bundles of these and other strongly scented herbs, and snuggle them up around newly emerging seedlings. This keeps the bunnies at bay until the plants are strong enough to withstand a little nibbling. The herbs don't wash away in the rain, and the protection lasts for weeks.
#18 – Slugs
We get a lot of wind, so I mulch heavily to keep the soil from blowing away and to retain moisture. Last year we had a cold, wet spring, which led to a boom in the slug population.
I tried beer traps. I took a sour cream container, buried it up to the edge in dirt, and put about an inch of beer in the bottom. It cleared out the area, and then I didn't catch anymore. I think you'd need a lot of these to be truly effective. Plus, one of the traps got dug up and something drank the beer! Not sure I want to attract drunken varmints.
The best for slug control I've found is diatomaceous earth (DE) or crushed eggshells. Eggshells are generally free, and you're not likely to inhale much dust from them, unlike the DE. Apply crushed eggshells generously on the soil surface wherever you have slug troubles.
#19 – Squash Bugs
Squash bugs are fast moving and breed very rapidly. The adults resemble stink bugs (some of which are actually beneficial) so when they first showed up in my garden, I didn't realize they were trouble. I soon learned the error of my ways. Squash bugs can suck and chew a plant to death in days. Look for egg clusters on the underside of leaves and smash them or scrape them into your soapy water.
Squash bug nymphs can be treated the same way. Neem oil is supposed to be effective on the nymphs if they are hit directly, but it didn't slow the ones in my garden down very well. Another option is to wrap a strip of duck tape around your hand, and press it against the eggs to lift them gently away from the leaf. You can use the tape to nap the nymphs, too.
By the way, the mature squash bugs smell like fruit loops when you smash them. I tried to get a picture, but they weren't cooperating. The young ones don't smell as strong, and they don't taste like much of anything, just “green”. (Yes, I ate some bugs last summer. I was curious, and figured it was time for payback.)
Also, I've recently started researching entomophagy (eating bugs) in more detail, and found out that squash bugs and many other common garden pest are edible. If you're curious, you can read Eating Bugs – Free Food from Your Backyard.
#20 – Squash Vine Borers
If you find holes in a squash stem that have a pile of what looks like sawdust next to them, you likely have squash vine borers. When I have clear borer signs, I carefully slice open the stem and remove the problem insect larva. After removal, I bury the stem in compost or rotten manure to encourage additional roots. (Mulching the vines may also deter further attacks.)
Keeping your squash vines covered until female blossoms show up will help keep your plants clear of borers. Cucurbita moschata varieties, such as butternut squash and Tromboncinos, are highly resistant to squash vine borers.