So there’s a ton of bugs in your garden eating holes in your beloved vegetable babies… you only know what a few of the bugs actually are… and you want to know how to get rid of them in a way that won’t harm the environment (Please note there are affiliate links present in this post, which means if you click on a link and buy something I’ll get like 4 cents for it. No extra cost to you).
I have lots of experience dealing with garden pests (in 150+ different farms and gardens!) but let me forewarn you: This isn’t another internet listicle on which OMRI-approved organic spray is better than the other. I’m just not a fan of using a ton of elixirs, whether they’re store-bought, homemade, chemical-free, what have you. I’ve been through that whole rigamarole – in fact, I even wrote an entire user guide on organic pest management once – but I no longer stand behind all of it. Some products are useful and even beneficial, but many are garbage and cause more harm to soil life than most people realize. The first step to knowing whether your bug problem is actually a problem or not, is educating yourself and getting to know your bugs. This article will certainly come in handy for that.
I’m going to lay it all out right here for you: The balance of bugs in our gardens is directly related to the health of our soils and the biodiversity of our Soil Food Webs. If you haven’t heard of the Soil Food Web nor have any idea how to organically build soil fertility, I highly recommend reading my 2-Part Soil Building Series: 5 Steps to Building Healthy Organic Garden Soil: Increasing the Biodiversity of Your Soil Food Web.
Every living creature in our gardens serves a purpose. There really are no “good” and “bad” bugs. Great organic gardeners realize the importance of all living creatures in their gardens. Even the hungriest, yuckiest garden bugs serve a purpose in the immediate ecosystem and Soil Food Web – most notably, they are someone else’s food. The fact is, bugs eat each other! They keep themselves (and harmful pathogens and diseases!) in check. When there is an abundance, or infestation, of any kind of bug, an imbalance has occurred.
I’m not a saint here. I’ve killed lots of “bad” bugs. I mean, lots of them. I’ve learned from previous garden teachers how they kill bugs, I’ve researched the internet high and low for the most effective products to kill bugs, I’ve even made concoctions up on my own as I struggled through killing multiple generations of the same family of bugs. Basically what I’ve learned is that it’s a mindless, costly game, and one that we’ll never win. In writing this guide, I hope to shed the knowledge and wisdom I continue to gain through careful observation, following my intuition and using a light, mindful hand in helping my gardens keep the “bad” bugs in check.
Compassion, even for the wiliest of creatures, is part of organic gardening. We pledge to take care of the earth, so let’s not be greedy and half-ass it by only keeping alive what we deem precious. If entire populations of aphids were wiped out, ladybugs would starve. And we need those girls!
Now, there are a few bugs that will always be present in your gardens, even with healthy soil food webs. Aphids are unrelentingly rampant if you are in an urban environment. And I have never farmed or gardened a plot of land without the flutter of white cabbage moths. Their spawn is something I’ve learned to deal with using a light hand, and meanwhile, I’ve come to appreciate their delicate presence in flight.
When we simply change our outlook on garden pests from hatred to acceptance and allow ourselves to recognize their needs and contribution to our ecosystem, a weight is lifted off our shoulders without doing any actual gardening at all. It’s not unlike the maladies of humanity represented in religious intolerance and racist ignorance. It’s mind over matter.
And now after all that “accept the bug” thought, I open up with quite possibly the most rampant and disgusting bug of all. Aphids have been a hard one for me to get behind. They are tiny fly-like insects that suck the sap out of a myriad of crops, flowers, trees and shrubs. They come in a rainbow of colors: black, green, brown, white, gray, red and orange. Their bodies are very soft and will collapse into wet goo under pressure (ie. your fingers). Because they feed in large groupings, they are very hard, if not impossible, to completely remove. The gray ones in particular will cluster themselves by the hundreds onto the backs of kale leaves or inside the folds of brussels sprouts… but alas, there are a few things we can do to help prevent and deter an aphid infestation.
Step 1 (Most Important Step): Release ladybugs. The best preventative defense against aphids is making sure their natural predators are prevalent in your garden. Ladybugs and their larvae eat aphids for breakfast, lunch and dinner – and releasing them in your garden will help keep aphid populations in check. Make sure to release ladybugs in the evening, and leave out water sources for them to drink, otherwise they will just fly away.
Step 2: Where infestations are really bad (usually the flaky gray ones all clustered together), jet them off with a hard stream of hose water. Remove vegetation that is heavily infested (like the photo above).
Step 3: Create a homemade aphid spray that, wait for it… actually works! And doesn’t harm beneficials! Here is my recipe for aphid eradication: 1 tbsp canola oil, 1 tbsp baking soda, 1 tsp castile soap – dump into a spray bottle with water and spray those suckers down.
Product Links: Live Ladybugs (I suggest purchasing at least 3,000 ladybugs)
2. Asparagus Beetles
I have witnessed, over the course of one season, asparagus beetles do a serious number on a well-established asparagus patch. The biggest problem with these beetles is they overwinter in garden debris and emerge with new spears in early spring (March, in the Midwest). The new spears become browned and “hooked” at their ends (totally inedible) while tall, whispy fronds are devoured in full by their grayish-green larvae, lessening the ability of the asparagus to set seed. Asparagus beetles live all three life cycles at once in the patch (eggs, larvae, beetle) while planning ahead and preparing a nice, warm home for generations to come. Right under our feet!
Performing all of these steps in combination will help keep your asparagus beetle infestation in check, but you must be diligent.
Step 1: Clean up all debris (mulch, fallen leaves, fallen fronds, etc) in your asparagus bed and in the immediate surrounding areas. As a gracious Soil Food Web builder it will be a heartbreaker to clean up your beds, but it must be done to lessen the amount of overwintered beetles.
Step 2: Handpick. Walk around your patch with a bucket of soapy water and knock as many beetles and larvae into it as you possibly can (watch out for the larvae heads – they squirt green goop – not even kidding). Search for rows of eggs (either orange or black) hanging discretely from fronds and squish them. Do this as often as you can.
Step 3: If you have a big larvae infestation, birds could be a huge help! I suggest setting up a bird feeder next to your patch and see if they will munch the caterpillars in between feedings.
Step 4: Again, release ladybugs! They feed on asparagus beetle eggs and will help keep a myriad of other pests in check.
3. Cabbageworms / Looper Worms
If you have big holes chewed through your brassicas (that is, broccoli, brussels sprouts, kale, cabbage, kohlrabi and company), or if the leaves are skeletized down to their ribs, it is most definitely the cabbageworm at work.
Cabbageworms and cabbage loopers are two different species of larvae but they cause the same type of damage. Most commonly seen is the cabbageworm – it is a bit fatter with yellow stripes running down its back (pictured). The looper is a skinnier version with white stripes down its sides, and it “loops” itself up and down in order to get around because it doesn’t have legs in the middle of its body.
I’ve never worked in a garden where these caterpillars aren’t present – but the good thing is, if you are diligent and get them in time, they will do minimal damage. There are a few initial signs to look out for cabbageworms. First, if you notice white moths fluttering around your brassicas, they are most definitely laying eggs. Second, when larvae are very tiny, they will eat the surfaces of leaves, leaving behind squiggly white “tracks.” Third, your leaves will have larger “blobby” holes in them (great adjectives today, I know). Time to get picking!
Step 1: If you have small children, catching cabbage moths with handheld nets can be quite fun for them. This will prevent more eggs from being laid on your plants. It also presents a great opportunity for teaching some serious Circle of Life lessons (those moths your kids caught – they’ve gotta go. I’ll let you handle that one!)
Step 2: Handpick. This is your absolute best line of defense against cabbageworms. Carefully look in the crevices and undersides of leaves – the worms are camoflauged to exactly the same color as green brassica leaves and can be really hard to find when they’re small. Many times they will hang out in the delicate, central growing tips, so carefully peel back those layers if you can. You can throw the caterpillars on the grass near your bird feeder (or treat your chickens if you have any!)
Step 3: Use Diatomaceous Earth (DE). DE is very fine powder made of diatoms from the ocean floor – it is completely harmless to humans, and most other living things, except soft bodied insects. When they ingest a leaf with DE on it, the powder rips their digestive tract to shreds. I’m okay with using this because it does not harm any soil microbes. It is important to sprinkle the DE on your plants in a thin layer like a powdered donut. Using a fine mesh sieve works great for this.
4. Cucumber Beetles
More like monsters! Cucumber beetles are little yellow insects with black stripes (or sometimes spots) on their backs. They lay dark orange eggs on the undersides of cucurbit leaves (cucumber, squash, pumpkin, melon). Their larvae feed on the roots and underground stems of plants, severely weakening them, while adult beetles feed on everything – foliage, blossoms and fruits. As they fly from plant to plant, they transmit diseases and can kill an entire field if left to their own devices.
Step 1: If you planted your seedlings in rows, consider covering them with row cover until they are well established and can withstand damage from the beetles. You’ll need enough Agribon to cover the row, wire hoops to elevate the cover off the plants (I recommend 18-24” height), and landscape pins to keep it all in place.
Step 2: Remove the dark orange eggs from undersides of leaves. You can squish them with your fingers, or gently remove them with duct tape.
Step 3: Release ladybugs. Again, these natural predators feed on the beetles’ eggs.
Brownish-gray and kinda bumpy, these caterpillars are about the size of cabbageworms but actually live in the soil rather than on the plants. Cutworms feed on the stems of plants, right at the soil line, weakening them from the bottom up. Overnight, they can completely hack away at the base of tender seedlings, knocking them all down, a heartless phenomenon not far off from total deforestation of the Amazon rainforest. Okay, maybe not that bad, but still maddening.
To deter cutworms from eating their way into your veggies, sprinkle a ring of Sluggo Plus around the outer edges of your plants. The active ingredient in Sluggo Plus is Iron Phosphate, which stops up their digestive tracts so they no longer feed. This product is also very useful for slugs, earwigs and roley poleys.
Product Links: Sluggo Plus
6. Flea Beetles
These guys literally look like, and hop around mindlessly like, regular old fleas. They love radishes, turnips and other small brassicas in the early spring, and will eat tiny holes all around the surface of the leaves (see right photo). I’ve really only seen flea beetle infestations on larger urban farms, where there are larger plantings in 20-foot rows or longer. If you have a smaller backyard garden, flea beetles probably won’t be a problem for you.
The only way you can keep flea beetles off your crops is to cover them with row cover – so if you know you have a flea beetle problem, plant your brassicas in rows and cover them up!
7. Four Lined Plant Bug
The first time I came across these neon guys was Summer 2015. They appear to eat everything. The damage they leave behind is a distinct series of brown dots all over foliage where, while slurping up all the chlorophyll they can, they secrete a toxin that kills surrounding cells. I’ve seen the biggest damage done to basil leaves. With their chartreuse jackets, rusty orange hats and affinity for fine herbs, clearly this is a bug with good taste.
Because this insect has such a short life cycle, there is really nothing to be done to stop them. They only live for a few short months in the summer, carry out their damage, and die off. I suggest simply handpicking by walking around and knocking them into a bucket of soapy water should you have a large infestation. Have a bucket lid ready cause they’re quite svelte and will fly out as soon as they’re knocked in. Also, remove any leaves that are browned and wrinkled so the plant stops using its resources to keep those leaves alive.
During spring soil prep, you might come across fat, white grubs with beady, brownish-black heads in your soil. These are actually the larvae of Japanese Beetles, and will morph into those pillaging, ravaging life suckers come the end of the summer. A few of these grubs in your soil is okay (max 4-6 per cubic foot of soil), but if there is more than that you will want to get rid of them. Consider feeding them to your chickens or throw them out on the grass for the birds to enjoy.
In this amazing shot, an ant is fixing to prey on this larvae – in the garden, everyone is always someone else’s food!
9. Japanese Beetles
They are beautiful, iridescent, they flutter with grace and carry armor on their backs, reminiscent of Ancient Egyptian relics. And my goodness are they attracted to each other. The amount of shameless fornication I have witnessed these beetles in is beyond belief. Their taste in plants isn’t far off from their taste in each other – they’ll settle on almost anything that’s alive. In the edible garden, this will most notably be the foliage of: grapes, raspberries, beans, edamame, peppers and eggplant. They munch the leaves until they are completely laced down to their skeletons.
The only step to rid yourself of Japanese Beetles: Handpick! I know you didn’t want me to say that. But you’ve got to knock them into the bucket of soapy water hell. The more often you handpick, the less damage your garden will endure – as in, you should do this nearly everyday between July and September. I never said organic gardening wasn’t a ton of work.
10. Looper Worms (see Cabbageworm #3)
Everyone’s always trying to get rid of slugs. I get it. They’re slimy and disgusting (God only knows why I will always, without fail, order the escargot when it’s on the menu)… But that slime that slugs secrete, while they slither across and through the soil, is so great for the soil’s structure that it’s hard to do away with them.
Slugs are actually an important part of the Soil Food Web – they are our Gastropods to be exact, and are a valuable food source for larger Arthropods (caterpillars, spiders, mites, flies, etc). And again, they secrete that slime that holds soil particles together, they create tunnels underground for air and moisture to penetrate plant roots, and really, the biggest damage I’ve seen them do is eat lettuce…
If you do have a big slug infestation, the best option is the old fashioned beer trick. Take an empty tuna can, fill it with cheap light beer, sink it down into the soil, and they will come. Slugs are nocturnal, so check and refresh your traps in the morning. Sluggo Plus also works, but I prefer to pay homage and treat my slugs to a drink on their way home.
Product Links: Sluggo Plus
Related Article: Epic Spring Planting Series: Tips for Planting with Seeds
12. Squash Bugs
I changed my mind about the aphids. Squash bugs are definitely my least favorite garden pest. If you’ve ever come across a stampede of baby squash bugs on the underside of a zucchini leaf, you know what I mean. If not, haha. Prepare for the biggest willies of your life.
Squash bugs do damage to plants in the cucurbit family that is similar to cucumber beetles. The baby beetles and adult beetles both suck sap from leaves and secrete a toxin that causes the plants to wilt. As they fly from plant to plant, they transmit disease. I’ve seen infestations so heavy that blossoms won’t even make fruit.
These guys are fast, so handpicking is tough. They scatter in a hundred different directions when they know they’ve been found. The best way to keep squash bugs in check is to take preventative measures:
Step 1: When planting a large crop of cucurbits all in one area, you can always use row cover. This will also prevent the cucumber beetle and flea beetles early on.
Step 2: Squash bug eggs and cucumber beetle eggs look incredibly similar – both dark orangey-brown. Early on, you’ll want to start inspecting your plants for eggs on the undersides of leaves and promptly remove any you come across. You can squish them with your fingers, or gently remove them with duct tape.
Step 3: Release ladybugs. Again, these natural predators feed on the beetles’ eggs.
Step 4: Get rid of old cucurbit plant debris! Squash bugs overwinter themselves in leftover plants, just like cucumber beetles, so lessen their chance of doing so by composting all of it.
13. Squash Vine Root Borer
Funny story about the lovemaking shot above: I was so enamored over the colors (and size!) of these beetles that I didn’t even think they could be detrimental to the health of this patty pan squash.. Went home, Googled it. Turns out they were squash vine root borers, in adult beetle form. I was horrified but also hilariously entertained over my dilemma. My client’s squash plant was definitely going to die.
These beetles lay eggs at the base of cucurbits (most notably squash and pumpkins) and their beige-colored larvae “bore” themselves inside the stems of the plants, eating their way through and killing the plants entirely. Vine root borers are a rampant problem in organic gardening and nearly impossible to prevent, but there are some things we can do to deter them.
Squash Vine Borer Damage by Larvae (Image Source)
Step 1: Row Cover. Same deal with the cucumber beetles and squash bugs. You can prevent the borer beetle from laying eggs at the base of your squash and pumpkin plants by completely blocking them out with row cover.
Step 2: If you don’t use row cover (which is totally normal and okay, by the way), you can deter the beetle with tin foil. By wrapping a small amount of tin foil around the base of your little squash seedlings, this repels the beetles by blinding them with bright flashy lights when they fly by. Think beetle rave in a really bad way. I like to bury the edges of the foil in the soil so nothing crawls up under it.
Step 3: If you notice “sawdust” under and around your stem, the vine borer larvae has most likely hatched, grown up, and gotten to work on your squash plant (see photo below). The sawdust looking material is actually very fine fragments of your squash vine being eaten alive. You can still save your plant by cutting into the stem vertically with a sharp knife and pulling the larvae out. Totally vile, but totally worth it!
Growing up, we had a charmer by the name of Chester, a pudgy, brown type who lived in our backyard and begged for peanuts. Yes, this squirrel literally came to the back door of the house and begged for peanuts! And I loved the little guy. Fast-forward 20 years later when I became an organic vegetable gardener, aka SQUIRREL HATER.
Fast-forward to a few years after that and I learned that the whole time those squirrels were taking single bites out of my clients’ tomatoes wasn’t because they’re conniving a^%holes – it’s cause it was hot out and they were thirsty. Poor sweet babes. Highly impressionable as I am, I hopped right back on the squirrel loving bus.
To prevent squirrels from taking single bites out of your tomatoes: Leave dishes of water out for them to drink! Your ladybugs will appreciate it too.
15. Sowbug / Pill Bug / Roley Poley
Again, I used to think roley poleys were the most delightful and innocent of bugs until I became an organic gardener. Turns out they know their way around a veggie garden – most notably, I’ve seen them eat their way inside the fruits of peppers and eggplants, and take entire bites out of green beans. They happen to play a valuable part as Arthropods in the Soil Food Web, munching their way through decaying plant debris and breaking it down for beneficial bacteria to do their work – but when roley poley populations are too high, they will go to work on living plants in the garden. And we just can’t have that.
To deter roley poleys from eating their way into your veggies, sprinkle a ring of Sluggo Plus around the outer edges of your plants. The active ingredient in Sluggo Plus is Iron Phosphate, which stops up their digestive tracts so they no longer feed.
Sluggo Plus is also very useful for slugs, earwigs and cutworms – but only use it if you have a serious infestation! Please do not sprinkle this product all over your garden because you saw one roley poley and two slugs. Remember that the “bad” bugs are just as important to our little ecosystems in our gardens as much as the “good” bugs are.
Product Links: Sluggo Plus
16. Black Swallowtail Larvae
This guy is actually as good as they come! – but so many people ask me about them so I want to spread the good news. The swallowtail larvae transform into some of the most gorgeous and colorful of butterflies – and are restless pollinators.
Now swallowtail larvae actually do feed on our gardens – parsley and dill are two of their favorites – and they will go to town and back on them. Do not kill them. If you know you have swallowtails in your garden, plan to have a separate patch of herbs and then move them over to that patch when they appear in your garden. They totally won’t mind, they’ll be so thankful, and they’ll delightfully keep on munching their own personal herbs.
Though similar to aphids (in size, and also being sap suckers), the damage thrips causes to plants is distinguishable from other small, soft-bodied insects. They feed in large groupings, on a myriad of vegetables and flowers, and damage on the leaves will go from color loss, to a silvery hue, to a complete dead wilt. The silvery hue is the key here.
There are thousands of species of thrips, they live basically everywhere, and also overwinter themselves. Luckily, I haven’t had trouble with them destroying anything. They are more just one of those gross little bugs that gets all over everything and sucks the life out of some flowers and leaves, here and there.
Step 1: Use my “killer” aphid spray (which I guess is now the Killer Aphid & Thrip Spray) – 1 tbsp canola oil, 1 tbsp baking soda, 1 tsp castile soap – dump into a spray bottle with water and spray them down.
Step 2: Release Ladybugs. Sit back and let the ladies do their work on all stages of the thrip.
Product Links: Live Ladybugs
18. Tomato Hornworm
These things are the freak show of your organic garden. If you’ve never seen one, it may have been because you weren’t looking hard enough. These caterpillars, which can grow up to 5 inches long, have the ability to camouflage themselves so well that I have literally sat and pruned a tomato plant for a grand amount of time before realizing one was hanging out right in front of my face. Waving its little orange horn at me.
Usually I will notice I have a hornworm problem with two observations: 1) There will be entire leaves and stems eaten overnight; and 2) There will be green frass everywhere. Frass = Turds. Yes, these things are big enough to leave piles of dark green turds on your plants. But let’s not get ahead of ourselves here, caterpillar turds are simply decomposed tomato leaves and stems and are a wonderful fertilizer for the garden!
More often than not, nature will take care of your hornworm problem for you. If you see a bunch of white eggs that look like baby Tic Tacs all over the back of your hornworms (see photo), the Braconid Wasp has done its work. Essentially, the egg sacs suck the life out of the caterpillar and in a few days, he will be black and shriveled up. Ruthless! If the wasps don’t pay your garden a visit, here is what you need to do:
Step 1: Handpick the hornworms off your tomato plants. It’s going to be hard. Trust me, I know. I’ve spent 15 minutes pacing back and forth and taking deep breaths the first time I had to touch a hornworm with gloves on. But they’ve gotta go.
Step 2: Do what you will with your hornworms. You could throw them on the grass for the birds or feed them to your chickens. Somehow, someway, they become part of the food chain.
19. White Flies
These are wispy, delicate little soft-bodied flies that convene in large populations, looking very much like the lightweight, silvery seeds of a dandelion. If only we could be so lucky! Like aphids and thrips, they are sap suckers. I have mostly seen them on tomato plants and in greenhouses. They are not easy to get rid of – when touched, they kind of “mush” apart and it’s impossible to get a hold of them with your fingers or knock them into a bucket.
In a Greenhouse: If you have a white fly problem in your greenhouse, I suggest using sticky tape. Stick it up everywhere. At least one piece per two square feet. White flies are stupid and will fly right into it. This is also useful for aphids in a greenhouse.
In an Outdoor Garden: If white flies have made their presence in large quantities, jet them off with a strong stream of water using a hose. This is tedious, requiring patience and a somewhat strong stomach. Once you jet them off, they won’t find their way back.
Product Links: Sticky Tape
Wireworms, not to be mistaken with centipedes, are inch-long rusty orange segmented larvae. They, like cutworms, live within the soil. These larvae particularly feed on root crops that grow beneath the soil surface – namely potatoes, turnips, radishes, carrots, parsnips and onions. It’s pretty unfortunate when wireworms discover your potatoes or turnips because they eat themselves in and around the roots, leaving unsightly holes that begin to decompose underground before harvest. There are a few preventative measures to take with these guys:
Step 1: Practice crop rotation, especially with root crops. If you know you have a wireworm problem, try to move your root crops around as much as possible and avoid planting in the same places within three seasons. This will greatly diminish your wireworm populations.
Step 2: Use bait. Cut a few raw potatoes and turnips in half, stick a fork in each end of them, and bury them in the soil, fork side up. These wet veggies will attract the wireworms and when you pull the fork out, you can dispose of the ones you’ve caught. Repeat as much as you need!
Whew! My stomach is queasy. So many bug pictures. If I left one out that you are stumped over, please leave a comment!