The physical control of pests is exactly what it sounds like, using physical mechanisms to help you rid your garden of unwanted insects. Not all of these solutions apply to every garden, so you need to familiarize yourself with who are your friends, who are your foes, and what techniques to use to maintain balance.
If you can see your garden enemies with the naked eye then a solution many gardeners swear by is to drag a shop vac out to your garden and suck up those little buggers. However, be sure to properly empty your vacuum bag into a garbage bag, secure it tightly and immediately put the bag outside in the garbage can. Insects can be quite resourceful so make sure the bag is secured tightly or they will crawl out setting back to square one. Some gardeners feed their chickens by emptying the vacuum into their coop, but I find this a messy and incomplete solution.
After you have harvested a plant for the last time pull the plant up roots and all, cut it up into smallish pieces and toss it in your compost bin. By destroying where insects reproduce you disrupt their life cycle thus eliminating them from your garden. This solution works particularly well on cucumbers, squash, asparagus, broccoli, and cabbage plants but is a good habit to develop across your garden.
A great solution for controlling slugs and snails is copper stripping. The copper carries a charge that interacts with the slime of these mollusks and gives them an unpleasant electrical shock. I have found this solution works best on raised beds but for thoseplants in the ground, you can buy copper rings that are placed around the base of the plant keeping slugs and snails at bay.
Cutworms are moth larvae that hide in soil and come out at night to dine on crops. They attack the stem of plants thus "cutting" them down. The best solution is to use a toilet roll to protect the plant stem from these little plant loggers. Some gardeners use yogurt cups or cans but ta toilet paper roll will decompose into the soil in about six weeks.
This technique is often referred to as handpicking. You simply identify the culprits on a plant and crush them. It can be a little time-consuming, but it works and helps you keep an eye on the health of your plants.
Using lightweight row covers will help keep your garden free of some unwanted pests. Row covers work well for spinach, broccoli, cabbage, cauliflower, peas, lettuce, and radishes.
The color of yellow sticky traps attracts insects and then traps in the sticky substance on the surface of the trap. Just hang the traps near the plants to be protected and then simply dispose of the trap once it has done its job.
2. Organic Insecticides
For your reference, I have first provided images of some of the most common garden pests so you can quickly identify them.
Colorado Potato Beetles
Grape Leaf Folder
Mexican Bean Beetles
Tomato Fruit Worm
Tomato Horn Worm
For Easy Reference
Next,I have listed these insecticides in alphabetical order which has no reflection on their importance or recommendation. For best results scan the entire list and look for the pests that you are experiencing trouble with.
DE often referred to as diatomite is a naturally occurring soft siliceous sedimentary rock that is processed into a fine white powder. The powder has sharp edges that slice into the bodies of pests which in turn cause death through dehydration. To apply DE start by squeezing a plume of powder into all cracks and crevices of the hardscaping around your garden any place insects can hide. You will also want to apply it to the base of plants venerable to insect infestation.
Pro Tip: Unfortunately, DE can kill beneficial insects to your garden so you will want to protect the treated plants with burlap for a couple of days. Be sure to spay the remaining DE off the plant once you uncover it.
This insecticide disrupts an insect’s respiratory system triggering suffocation and death. Usually, frequent applications are needed to get infestations under control. To apply spray the plant and the soil around the plants you wish to protect.
Pro Tip: Horticultural oils work best when applied in cool weather.
Insecticidal soaps break down the cellular membranes and protective waxes of insects that then cause the insect to die via dehydration. To apply insecticidal soap spray the mixture directly to both sides of the leaves and into any applicable crack/crevices in hardscaping. Additional applications will most likely be needed to get the pests under control.
Pro Tip: Although there is commercially insecticidal soap available you can make your own at home by combining a ratio of 1 tablespoon of liquid dishwashing soap to 1 quart of water.
Neem is an interesting insecticide that reduces an insect’s appetite, slows their development, and eventually stops them from laying eggs. Neem oil is derived from the natural oil found in seeds of the neem tree, native to India.
Pro Tip: Neem affects young rapidly growing insects the best.
Derived from the bacterium Saccharopolyspora Spinosa it produces a substance that acts as a neurotoxin damaging or destroying an insect’s central nervous system.
Pro Tip: Spinosad is fast working, and you’ll see results within two days.
Works best on:
Caterpillar, Colorado potato beetle, Blister beetle, most leaf-eaters
3. Beneficial Insects
A garden that is full of insects is an indicator of a healthy and happy garden. A large variety of insects in your garden indicates that both pests that destroy your garden and the insects that dine on those pests are present.
When gardens become infested with pesty garden destroying insects it is often necessary that we step in and help beneficial insects regain dominance.
It’s the circle of life thing, we plant, pests destroy, and our beneficial insects (with a little help from us) eat the pests thus maintaining a healthy balance in the garden.
To get a good handle on what’s going on with the insect population in your garden you need to regularly engage and examine your plants closely as they mature. It’s easy to overlook tiny little creatures so take the time to note the kind and number of insects making a home in your garden.
The following beneficial insects feed on other insects, either as a predator or a parasite. They help fight bad bugs from doing more than minor damage to your crops.
Simply click on the image below to jump directly to that insects data
Minute Pirate Bug
If you are uncertain of what a particular insect is, take a picture of it and compare it to the insects pictured in this post. If you still can’t identify who is who use Google Image search to narrow down your results. To further help confirm your findings use IPM Images which bills itself as “The Source for Agriculture and Pest Management Pictures.” What’s cool about this site is that you can just describe the insect in the search box which will return a plethora of images and descriptions to choose from.
Once you have identified the insect use this post to determine which physical pest control or organic insecticide to try and which beneficial insects you want to attract. It may take several attempts to get pests under control, but the recommendation found here are tried and true so be patient and persistent until you are successful.
Assassin Bug (predatory)
Usually brown or black in color but some may have vibrant red, orange, or green bodies. Approximately one inch in length, shield-shaped backs, around protruding eyes set into a long, tubular head. It's a good idea to practice some caution around these bugs because they can bite humans and animals even when unprovoked. They break the skin with a sharp beak and inject their venom into the site which can swell and become painful but rarely requires a doctor's visit.
Assassin bugs can be found in the United States predominately in Arizona, California, New Mexico, and Texas. Although they do like the weather in the hot and sunny states they are now being found in states further north possibly because of warming temperatures due to climate change.
Braconid Wasp (non-stinging, predatory and parasitic)
One-half inch in length, dark brown or black with narrow abdomens and long antennae. These insects release their eggs along with polydnaviruses inside or on other host insects. The eggs hatch and consume the host from the inside out.
All across North America, Europe, and other temperate climates.
The smell of caterpillars eating the leaves of plants, weird, right?
Ground beetles come in a variety of shapes, most have a glossy black color, and others are orange, green, yellow, and even iridescent. Their bodies are flat with ridges running the length of their wings. They have long legs and powerful mandibles and sharp mouths that they use to tear apart and eat their prey. These beetles either hunt for their next meal on the surface of your garden soil or the dig tunnels to trap unwanted pests. You will find these little guys in your garden soil around compost piles and under the protection of perennial plants.
They can be found everywhere, in the mountains, on the coast and, throughout deserts, as long as there are other insects to dine on they'll be there.
Adults bear a resemblance to yellow jackets, bees or wasps with black and yellow stripes. The maggots will transverse over vegetation feeding on small insects. They don't harm humans but to stave off predators they mimic the behaviors of stinging wasps with a hover and dart style of flight.
You will find hoverflies all over the world except Antarctica
They have green bodies approximately one-half inch in length, delicate net-like wings, and round golden eyes. Although they have those big net-like wings they are actually pretty poor fliers. These little guys have a voracious appetite for aphids and one Lacewing can consume more than 500 aphids within their one to three-week feeding period. After their multi-week feeding period, the larvae mature into adults and switch up their diet to nectar. Lacewings are nocturnal feeders so if you have coverings on your plants you’ll need to pull back the covers in the evening so that they can get those pesky aphids.
You will find Lacewings all over the world in temperate or tropical climates.
Everybody loves the lady and it's highly recognizable round/oval, convex orange/red body with black spots or no spots at all. Lady beetles are defiantly your friend in the garden. If you have ladybugs in your garden check plant leaves for clusters of yellowish/orange eggs that hatch larvae that will consume several insects in a day.
Ladies can be found in cities, forests, grasslands, and riverbanks throughout Europe and North America.
These bugs are tiny, approximately 1/8” in length with black and white flattish oval bodies with bulging eyes. . They are insatiable predators throughout their entire life cycle so they can be released at any point in their development. They feed on their prey by sucking the fluids of out of their bodies through a long needle-like mouth.
Commonly found in yards, gardens, woodlands, and pastures across southern California, the eastern and the southwestern United States, Mexico, and Central and South America.
Caraway, Cosmos, Marigold
Aphids, Corn earworm, Thrip, Whitefly
Praying Mantis (predatory)
These guys are big and vicious predators. They have a squarish head positioned on top of a long neck and bodies that resemble little branches or twigs. They can morph their color to match that of the foliage around them making them an extremely efficient apex predator. They consume just about every insect imaginable and have even been recorded attacking small birds and snakes. The Praying Mantis is found in many differing habitats. They are generally located in the s. Most species live in the tropical rainforest, although others can be found in deserts, grasslands, and meadowlands.
They prefer the warmer tropical and subtropical regions and can be found in forests, grasslands, and deserts,
Cosmos, Dill, Marigolds
Caterpillar, Crickets, Flies, Grasshoppers, Locusts, Moths, and just about any bug that moves
Soldier Beetle (predatory)
They have elongated soft straight-sided bodies, one-half-inch soft bodies and are easy to spot with their red or orange. These beetles are soft-bodied, straight-sided beetles. They can be found all over the world and thrive in many climates. They are also commonly called leatherwings because of their soft forewings located on their second thoracic segment. These beetles are attracted to goldenrods, marigolds, daisies, and other thick foliage.
Throughout the United States and Canada
Yellow pollinating flowers
Aphids, Caterpillars (small), Beetle larvae (other beetles), Grasshopper eggs, Moths, and Other soft-bodied insects
You are probably familiar with spiders because it is likely you live with several different types. There are over 45,000 different species of spiders so there is a wide variety of shapes and colors. However, all spiders have eight legs and two body sections the cephalothorax (front) and abdomen (rear). Most garden-friendly spiders don’t spin webs but dig shallow underground burrows where they trap their prey. Lush perennial bushes and compost piles are common places to find these industrious predators.
Spiders can be found in every habitat on the planet save for the polar regions, oceans, and high mountains.
Bright lights and flying insects
Feeds on: Aphids:
Flies, Grasshoppers, Wasps
Tachinid fly (parasitic)
This is a huge family of flies with over 8,200 know species that can be found all around the world. They like laying lay their sticky eggs on an insect so that when the maggot hatches it will dine on its host. They also like laying eggs on vegetation that other bugs eat which in turn then hatch inside the prey and then the maggots eat the host from the inside out. Attract tachinid flies by growing plants that bear umbels of tiny flowers. Buckwheat, carrots, cilantro, dill, Queen Anne’s lace, and sweet clover are among the crops that fit this bill.
In North America alone there are over 1300 species of tachinid flies and over 10,000 worldwide.
Armyworm, Cabbageworm, Cutworm, Grasshopper, Japanese beetle, Leaf roller, Squash bugs
Trichogramma wasp (parasitic)
These tiny little buggers are so small you can’t see them with the naked eye. They lay their eggs inside the eggs of other insects, which then develop into internal parasites that destroy the host internally.
These wasps live almost everywhere and in a variety of environments including aquatic habitats.
Common hosts include:
Cabbageworms, Codling moths, European corn borers
Wasp (stinging, predatory & parasitic)
They have meager little prickly stingers that they can effortlessly and repeatedly sting their prey with. Gardeners usually love wasps because they attack a huge variety of insects. With over 200,ooo species of wasps they are considered one of the most diverse creatures in existence.
All over the world in almost all climate zones except for Antarctica.
Sugary human foods, especially rotting fruit
The Insect Wrangler
The world of insects is a fascinating one and is easy to "go down the rabbit hole" learning about their weirdness and wonderfulness. As it turns out the most ferocious predators are actually our friends and you’ll always get by with a little help from your friends. Have fun and try different solutions until you find what works for you.
See you in the garden.
Join us in our quest at blendedtribes.com to save the planet one kilowatt, one therm, one garden (aka a 'Better Choice') at a time. You will be joining a group of like-minded individuals with a common goal and a common purpose.
Please consider taking action on any of the tips or recommendations found on our site to create a more sustainable, healthy, and abundant life for yourself and those you care about.
GWC - Sustainable Living Checklist
When you visit our site, take the Green Warrior Challenge to establish where you stand on your sustainability journey. It will inspire you with actionable line items that you can take that will increase the quality of your life and contribute to our collectively saving the planet.