23 Beneficial Insects and How They Support Your Garden
But what if I told you not all insects were bad? And in fact, you absolutely want a population of beneficial garden insects to take up residency in your yard. But the problem still remains concerning how to keep the good ones alive and not accidentally off them while gardening. The first step in providing your common beneficial garden insects a safe place to live is by first being able to identify them. Once you have this figured out, you may find that getting rid of the bad bugs begins to take care of itself.
Table of Contents
- Aphid Parasite
- Aphid Predator
- Assassin Bugs
- Beneficial Nematode
- Braconid Wasp
- Damsel Bug
- Fly Predator
- Fungus Gnat Predator
- Green Lacewing
- Ground Beetles
- Lady Beetle
- Leafminer Parasite
- Lightning Bug
- Mealybug Destroyer
- Moth Egg Parasite
- Pirate Bug
- Praying Mantis
- Spined Soldier Bugs
- Spider Mite Predator
- Tachinid Flies
The following is a good overview, but still an incomplete list of beneficial garden insects. There are approximately 91,000 different insect species in North America alone (amongst the 10 quintillion total in the world). Of these many are beneficial in some manner, and so, therefore, it is pretty much impossible to provide you with every species, genus, or even family of each insect you should be aware of. Instead, I’ve provided you with a decent overview of the most common insects seen within gardens of North American that you may already recognize in some manner.
– Aphid Parasite
The aphid parasite is a small wasp that lays its eggs in aphids. When the eggs hatch the tiny larvae eat the aphid from the inside out. Other aphids send up distress signals during this process, causing many to fall off the plant and die. Although the whole thing this may sound pretty yucky, this is done on such a microscopic scale it isn’t even detectable to the human eye. The larvae then transform into adult wasps and begin the cycle all over again. Aphids can make short work of your roses and other plants by sucking the nutrients from the plant. A heavy infestation can kill weakened or young plants, so the more wasps the merrier.
– Aphid Predator
Also known as an aphid midge, these tiny flies eat the honeydew left by aphids, and then lay their eggs within the aphid colony. Once the larvae hatch, they enthusiastically devour any aphids they can get to, often wiping out entire colonies as they grow. These are very popular insects within greenhouses as they breed quickly and are extremely effective in keeping aphids from taking hold.
– Assassin Bugs
Assassin bugs make up a good sized amount of the Hemiptera order of insects defined by their sucking mouthparts. Unfortunately, some Hemiptera can do some serious damage to your plants, but those defined as assassin bugs are those that use their sucking power to feed upon one another. Although Assassin bugs will generally feed upon ALL insects (including some bees) that get in their way, having them around can be quite beneficial as they will eradicate those making a meal out of your garden. If you see them and are concerned about other beneficial insects you have, they are easy to remove by hand and placed in adjoining fields or other properties where they can help keep down surrounding insect populations.
Mason bees, honey bees, bumble bees, cutter bees, sweat bees, carpenter bees, green bees… pretty much any bee is considered a pollinator and is something you want around. Most bees are completely harmless unless they feel they need to defend themselves, and simply go about their business and pollinating as they go. You can influence how often they visit your yard by keeping blooming vegetation through the seasons and leaving them alone to work or rest as needed. Early in the season, you can also place out small bowls of sugar water for them to take advantage of when flowers are yet to be plentiful.
– Beneficial Nematode
Although these are not technically insects, and you most likely will never know if you have them or not (although you can add them to your soils)- beneficial nematodes are likely the most beneficial ‘insect’ in garden soils to have around. These are non-segmented worms that are parasitic and search out harmful insects that lay their eggs on the ground to attack the immature stages by eating them from the inside out. Weevils, Japanese beetles, and fleas are only a few specimens that devour with relish. These are some of the best critters you can add to your soils, especially for indoor gardening, to help keep any pests that hitch a ride in soils from hatching and wreaking havoc on your plants.
– Braconid Wasp
These tiny parasitic wasps inject their eggs into the bodies of caterpillars, moths, insect larvae, etc. after which they hatch, feast, and spin their own cocoons upon from which the adult wasp will emerge. Although they may not kill their host outright, the host eventually will die from their infestation and serve as a transport, meal, and home until this occurs. Their favored host is the tobacco hornworm caterpillar, so if you find one of these large caterpillars in your garden (they love tomatoes) with what looks like a sack of white eggs along its back, let it be so the wasps may hatch unharmed.
– Damsel Bug
These are small, tan, slender bugs that resemble assassin bugs (they also belong in the order Hemiptera) and are found primarily in crop fields. They feed upon almost any other insects, particularly those that can be found in abundance amongst alfalfa, soybean, corn, and potatoes. They can be very influential in helping to keep harmful insects away from your own garden crops. If you happen to live near any crop fields, especially those that are not grown in rows, simply gather a few up with a net and spread them throughout your own gardens.
– Fly Predator
These are tiny insects that prey upon nuisance flies, including common houseflies. They seek out the pupa stages of flies, lay their own eggs inside to consume the maturing, unhatched larvae, and then hatch a few weeks later to begin the cycle all over again. Although these are not directly beneficial to your garden, they can help control fly populations that like to breed in your compost or other decaying matter and help around livestock as well.
– Fungus Gnat Predator
Fungus gnats, springtails, thrips, and other plant-damaging insects are no match for these incredibly small mites that attack and feed upon the larvae laid within the soils. Practically microscopic, these mites attach themselves to soil-borne larvae and literally suck them dry before moving on to their next prey. These are popular predators to spread within greenhouse garden plots and organic gardening soils to help ensure healthy plant growth uninhibited by destructive, sucking insects.
– Green Lacewing
Soft-bodied insects and eggs are no match for the Green Lacewing. Although delicate in nature as its name suggests, these are deadly flying creatures that as adults feed only on nectar and pollen (and are actually decent pollinators). But when they first emerge from their eggs, they are known as aphid lions and can make a fast meal out of a colony of aphids, or other soft-bodied insects and their eggs, inhabiting the same space they are.
– Ground Beetles
If you see a large beetle scurrying across the ground, it really is to your benefit to leave them alone. Many beetles feed upon slugs, snails, grubs, cutworms, maggots, and any other small creature that happens to get in their way. Some eat animal waste and help speed up the decomposition process, while others may scavenge and feed on dead animals or other organic materials as well.
More popularly known as Daddy Longlegs, Harvest Spiders, or Shepherd Spiders, these insects are often confused with a spider. Although they are of the animal class arachnid (as is a scorpion, tick, or mite), they have an entirely different order of classification than what we commonly refer to as spiders. This is mainly because they have only two eyes and one body segment: rather than the eight eyes and two body segments of spiders. Harvestmen are wonderful hunters and make a fast meal out of aphids, caterpillars, flies, mites, ticks, slugs, snails, and small spiders. Of course, they may not always feed on pests and make the occasional meal out of a helpful spider, having them around is generally a good thing for your garden health.
– Lady Beetle
Lady beetles, ladybugs, and ladybirds are all names used to describe the small red and black beetle popular in old wives’ tales and children’s stories to bring good luck. And these stories arose for a very good reason as they are a harmless, friendly looking bug who’s exterior hides a vicious appetite for soft-bodied insects in all stages of their life. If you see them amongst your garden, you know you are in good company as they will help eradicate anything feeding upon your delicate blooms and vegetation.
– Leafminer Parasite
Leafminers are the larvae of various insects that burrow between the two surfaces of your leaves and leave behind a distinctive meandering maze-like pattern that eventually kills the leaf. Infestations of these can result in poor photosynthesis processes of your plant and can weaken the plant, making it susceptible to disease and other insects. The leafminer parasite is a wasp that lays its eggs within the ‘maze’ to feed upon the larvae. This helps break the lifecycle and eradicate the problem.
– Lightning Bug
The many different species of lighting bugs found throughout North America enthrall entomologists worldwide. Their distinct patterns of light are a science all in itself, but what many people are unaware of is that they are much more than a fun summer evening entertainment. The larvae of these bugs (and some adults) feed heavily on slugs, snails, and other soil insects as they mature. Having them in abundance in and around your property helps keep these populations under control, and should make you take care about soil treatments to allow them to mature and breed for future generations.
– Mealybug Destroyer
Although not native to North America, these lady beetle-like insects have called it their home for over 100 years and have been beneficial in helping to eradicate mealybugs, scales, and aphids within gardens. These little beetles are usually black with a tannish-red head area and seek out infestations of sucking pests within which to lay their eggs. Their white, fuzzy looking larvae (which shouldn’t be confused with a mealybug itself) then hatch and feed upon all stages of the insects before maturing and pupating into adults. Each beetle lives approximately 2 months and can lay up to 400 eggs each life cycle.
– Moth Egg Parasite
These tiny, parasitic wasps are a yellowish orange in color and can sometimes be confused with gnats- but are incredibly beneficial to your garden. A killer of over 200 species of pests, these little wasps use scent to seek out suitable hosts within which to lay their eggs. Since they lay their eggs within other eggs, essentially, they help stop the damage to your plants before it even has a chance to begin.
– Pirate Bug
Soft-bodied pests are no match for the Pirate Bug. Both wingless larvae and flying adults will feed upon common nuisance pests found in your vegetable garden. Spider mites are especially of interest to them, as they can feed upon up to 30 in one day. Two to three generations can hatch within one growing season, and they are often found within crop fields, as well as grassy, wildflower-filled fields. They are also easy to catch with a net as they have a distinct tan and black, V-shaped color pattern on their wings. Then they can be deposited in your own yard to help with any pest you feel you may need help getting rid of.
– Praying Mantis
A Praying Mantis will feed upon anything of size that gets within reach and can be quite violent when doing so as they are considered a deadly catch. This includes beneficial insects, as well as the occasional human finger (if provoked as they are not considered aggressive except when hunting). They are not venomous, however, and can be quite responsive to being kept as a garden pet since they will stick around your yard if provided enough to eat. They are wonderful to have since they do take care of more mature pests and generally will not create havoc in beneficial insect colonies.
– Spined Soldier Bugs
A Soldier Bug is a type of Stink Beetle and falls under the category of our Assassin Beetles. It happens to be a very commonly identified one, however hence why I am placing it here on its own. This flattened, light brown bug looks a bit like a tiny leaf with legs and a spiny back. It also can have some color variations of darker brown or patterns depending on its maturity. It can grow close to an inch long, and with its elongated proboscis’ mouth, loves to pray upon crop-damaging grubs, caterpillars, borers, loopers, worms, and beetles.
Although not insects, spiders will usually feast on anything that happens on their web or crosses their path. Having them around is a great indicator of garden health. They actually may be the single most beneficial biological control of outdoors pests despite their appearance which is not always well received by homeowners. There really is nothing to fear from spiders, however of the approximate 3400 species of spiders that reside within North America, only four have any true venomous properties that can cause a serious reaction in humans. Try to leave these 8 legged critters to themselves unless you have worries about the species they belong to, and it never hurts to learn to identify the ones you see around your property to help you with this.
– Spider Mite Predator
Another arch enemy of the spider mite (which can do some serious damage to your vining plants) is the Spider Mite Predator. Although actually related to the pestilent mites they feed upon these carnivorous little creatures and are usually present wherever you have a spider mite infestation. Unfortunately, they often cannot eradicate the pests on their own and often are wiped out by pesticides during mite treatment. Because of this they actually make an excellent choice to add to indoor and greenhouse gardening setups to help keep pests from getting a foothold.
– Tachinid Flies
Similar in nature to a Braconid Wasp, these little flies lay their eggs on garden pests, in areas where garden pests can consume them, or inject them into garden pests. Any of these ways eventually results in the larvae hatching and feeding upon the host- which it will eventually kill. Unfortunately the host will still continue to feed upon your plants, but it will be unable to complete its life cycle– and these flies can be quite effective in helping to eradicate an infestation of problematic insects.
The single, most important way to attract beneficial bug to your garden is to feed them. Many of the adult stages of the insects above feed on pollen and nectar, so if you have a bountiful blooming garden from spring through fall, they will be attracted. Once these insects begin to feed in your gardens, they will stay and lay their eggs, hence repeating the cycle. This is an excellent way to begin organic gardening practices.
Keeping water available during dry spells is also a way to keep what you have attracted around. This is especially true of gardens found in more arid climates. Insects will seek out moisture and will stay where it is available. Of course, this means pests will be attracted to, but hopefully will be outweighed by the good. Mulching and leaf litter is a way to provide good cover and a home for early stages of these insects as well.
You also can purchase many of the good insects to come live in your garden. Be sure to research companies that offer live sales of insects, check shipping times, and suggestions as to when you should release them during the season. Most of these come in eggs, or as newly hatched larvae or immature stages.
Unfortunately, when we attempt to control insect infestations using both chemical or organic defenses, good bugs are often a casualty to these treatments since they are susceptible to the same poisons and techniques that kill the bad guys. Since good and bad bugs are both often located in the same areas as one another, you may find that you want to take a new approach to how you treat your yard against destructive pests. The first step towards keeping your beneficial insect colonies intact is to be able to correctly know what you are looking at and being able to determine whether each is a friend or foe.
I am completely guilty of falling prey to the ‘only good bug is a dead bug’ mentality. This is especially true when I have missed the early warning signs of insect damage and end up overtreating everything in my attempts to wipe out my garden bug population in one fell swoop. Unfortunately, this type of practice is horrific for your beneficial insects, and there are few tips to help keep them thriving despite the steps you may take to wipe out the harmful culprits.
– Avoid Harsh Pesticides
Of course, there is nothing wrong with using insecticides when your garden is at serious risk of being overrun with pests. Always try to use the least harsh pesticides and avoid using incorrectly or applying a wide application unless absolutely necessary. Check for when your beneficial insects are most active before using and look for those that need a direct contact application so you can get directly at what is causing havoc with your plants rather than leaving a poisonous residue behind.
– Read Labels
Read your labels to ensure you are treating the pests correctly and using the insecticide as it should be used. Often applications are not applied to plants in the correct manner, which can cause harm to the plant and leave the insects untouched. Some insecticides are more specific to certain types of bugs, leaving other unscathed. These can be extremely helpful if you know exactly what you are up against.
– Use Insecticidal Oils and Soaps
Oils and soaps are good choices for large-scale infestations and require direct contact with the bug, but will not provide a long-term poison behind for other insects to be harmed from. Often these can be used with a sprayer to get underneath and within the foliage to ensure you are treating the insect causing the problem.
Take care in watching your plants for damage in order to assess what problems you may have and try to determine which bugs are after your vegetation. If you and identify the culprit, you are better able to apply the beneficial insects you need or apply a pesticide or insecticide to get rid of the pest- and keep the ones you need.
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