Your Beneficial Insect Army – We Salute You!

Posted by Chris Field
February 25th, 2009
Filed in Garden Pests and Diseases
Tags: aphids, beetles, beneficial insects, bugs, dragonflies, ladybugs, pests, slugs

You might have heard a lot about beneficial insects in your garden, and how they fight on your side to keep your flowers, shrubs and vegetables safe. Well, it’s time to meet these tireless, hungry soldiers, how to attract and keep them in your garden, and the pros and cons of using them as your organic insecticide. And how effective are they, really?

Introducing Your Garden Soldiers

If you are an organic gardener, chances are you will see a lot of these insects. If you use pesticides, you won’t. This is because most of these bugs are susceptible to most common broad-spectrum sprays. Unwittingly, you will kill a lot of the insects that could have helped you get rid of the pest in the first place. As 95% of the bugs in your garden are either beneficial or innocuous, that’s quite the “collateral damage” of killing one pest species.

That’s not to say that attracting, raising or even buying beneficial insects to kill a pest eating your favorite roses or cabbage will suddenly be solved overnight – mother nature doesn’t work that way. Generally speaking, once a pest insect runs rampant in an area, a predator insect will eventually discover this sudden, rich source of food. They will then lay eggs in the area. The eggs hatch, and suddenly their young will have a great start at life. Only then will the problem be under control.

As you can imagine, this process doesn’t take a day. It could take weeks or months. Or it may never even occur. Meanwhile, your beloved plants will be completely desiccated, and the pests’ appetite (and, most likely, the next generation) will move on to surrounding plants.

Gardening naturally certainly doesn’t mean avoiding giving a helping hand. You have to actively promote and encourage your soldiers to rally. Think of yourself as a general. As a general, you have to recruit and become familiar with your army. Here’s some of the main players:

Ladybugs
Ladybugs, also known as Ladybirds, are one of the most voracious carnivores in the insect world, especially in the larvae stage. With over 475 different species in Canada and the U.S. (at last count), they are also extremely prolific. During their entire lifetime they could eat 5,000 aphids! They’re also pretty to boot.
Attacks – Depending on the species, they eat aphids, mealybugs, younger caterpillars, scale, insect eggs and spider mites.
Cons – Ladybugs will often leave an area if food isn’t found. The Asian Ladybug will often enter homes in the fall, becoming a nuisance (but won’t actually harm anything except overripe fruit left on a counter.)
Where to Buy – You can purchase 1500 Live Lady Bugs by clicking the link. They’re specially fed to encourage the laying of eggs after being released in your yard. Needless to say, place them near the problem infestation, and at or just before sunset.

Lacewings
Lacewings are graceful insects with green bodies and gossamer wings, and a great alternative to ladybugs. The larvae will stay in your garden and busily munch on your pest insects.
Attacks – mites, aphids, whiteflies, mealybugs, moth eggs, thrips and other soft-bodied insects.
Cons – Adults will likely fly out of your garden. I guess the pastures are always greener elsewhere, especially if your pest problem is solved!
Where to Buy – Lacewing Eggs are available here. You will receive them as eggs, about a thousand of them. Place on the affected area. Some may have already hatched, so immediately release them. They’re hungry, eating about 60 soft-bodied insects like aphids per hour, but will eat each other if nothing else is available. So much for brotherly and sisterly love.

Parasitic Wasps (Trichogramma)
As scary as the name is, they don’t look like wasps (in fact, they are very tiny so you may not even see them), and they won’t attack you. However, yes, they are very scary, as in, the movie Alien scary. (Maybe that’s how the creators came up with the idea!) Yes, they do everything you think they do. The adults deposits their eggs inside the eggs of caterpillars and worms, then eat them alive inside out. Wow, brutal, but extremely effective. They are widely used by organic fruit growers.
Attacks – The eggs of caterpillars, cabbageworms, tomato hornworms, corn earworms, codling moths, cutworms, armyworms, webworms, cabbage loopers, corn borers and 200 other types of moth worms.
Cons – Besides the brutal nature of how they destroy their pests, the adults are easily blown away by the wind.
Where to Buy – Garden’s Alive can ship packages of about 4,000 Trichogramma eggs on strips within a protective box.

Minute Pirate Bugs
Aarrr! These are your most versatile warriors, feeding on a wide variety of pests. Best of all, they will likely stay in your yard after the infestation is solved, if they can find pollen-producing and blooming flowers.
Attacks – A wide-range of pests, including the eggs, larvae and adults of thrips, mites, aphids, whiteflies and young caterpillars.
Cons – Not much, except that they will leave if no food is found. A natural response for any living creature, I’m sure.
Where to Buy – Arbico Organics sells adults in packs of 500. Release them in the troubled area, and make sure you talk like a pirate while doing so. They will lay eggs in the hidden areas of plant leaves.

Nematodes
There are good and bad nematodes, but we are obviously talking about the good ones. They are microscopic worms, and when you hear the phrase “good microbes in the soil”, nematodes will likely be part of this. Your good army are called parasitic nematodes, and they bore into pests to feed. Within 2 days, a bacterium will kill the host, and the nematode simply leaves and looks for another pest to snack on. With the right conditions, such as moist soil and a warm temperature (60 – 90 F), they can actually clean up over 80% of pests in the soil.
Attacks – Over 250 soil-dwelling pests, such as root weevils, white grubs, slugs, snails, flea larvae, cutworms, borers, and Japanese beetle larvae. They do not attack earthworms.
Cons – They do not attack above-ground insects, and in drier or cold weather they won’t be as effective. In more northern latitudes, they won’t survive cold winters.
Where to Buy – Purchase a pack of a mere 10 million nematodes at Garden’s Alive. Mix with water and spray on your lawn and along the soil in flower and vegetable beds. With the right conditions, they will live and reproduce indefinitely. Otherwise, apply every spring.

Dragonflies
My favorite insect! The majestic dragonfly, with iridescent wings and colorful bodies are always a joy to see. They can hover in mid air, then suddenly zoom at 35 MPH. Heck, they even mate in a way that looks graceful! The larvae hatch in ponds and other wetlands, where they feed on mosquito larvae, and as adults they perform like eagles or Apache helicopters, attacking and feeding on a variety of pests.
Attacks – Mosquitoes, flies, gnats, flies, ants, termites, and any other flying insect. These are the Marines corp of your garden (Get it? Because they live near water? Ha ha?)
Cons – None, but I might be biased. The only con is that they don’t actually live in your garden, but fly from place to place, eventually returning to a wetland area. So a more proper term for them would be hardy, tough mercenaries.
Where to Buy – It is not recommended, as they are “wild” and will not stay in your garden. Plus, there are no companies raising them en masse for commercial sale. However, in a future article I will discuss ways to attract them to your garden.

Ground Beetles
Beetles comprise the largest number of species in the insect world (over 350,000 different types and counting), and include about 40% of all insects. Many are good, many are bad. The lady bug is a beetle. What we’re concerned with, though, is the common ground beetle (aka carabids), the warhorse of your yard. With their shiny black shells, they are easily recognizable. If you see them in your yard, say “good job, Private!” They are busy keeping your garden clean and pest-free.
Attacks – Weed seeds, most pest insect larvae, insect eggs, moth larvae, caterpillars, wireworms, etc
Cons – They can become a nuisance in large numbers
Where to Buy – No need, they are everywhere. Many farmers are building beetle banks to encourage beneficial beetle populations to help control insect pests on farmland.

Centipedes
Though these are certainly creepy-crawlies, they are predators for a variety of ground insects. They and millipedes are excellent for the composting process as well.
Attacks – slugs, snails, fly pupae and other insects along the ground
Cons – Ever see one in your basement? Ewww!
Where to Buy – No need, they are everywhere. To encourage them, don’t disturb your soil too much after spring, and keep certain areas of the soil moist for them (not near your house, or they’ll find a way inside!)

Praying Mantis
An extremely beautiful insect I love seeing in my garden. Heck, many people keep them as pets! They are extremely effective predators, eating larger insect pests that other predators can’t touch. If you have giants with big clubs in your army, this would be the praying mantis.
Attacks – As a youth, it goes after aphids and mosquitoes. As it grows it will take on spiders, moths and grasshoppers.
Cons – Praying mantids do not congregate in groups, so although they have a wild appetite, they are not as effective as other insects in larger numbers.
Where to Buy – Arbico Organics sells them, but I wouldn’t bother, as there are much more effective troops. What’s better, three gleaming tanks in your army, or ten thousand tough soldiers with bazookas?

Predatory Mites
If you own a greenhouse, and some of your leaves are starting to get white spots on them, and then fine webbings around the plant, you likely have a spider mite problem. Time to show them who’s boss – the predatory mite! There are several beneficial mites that feed on pests, with the Phytoseiulus persimilis being the most common treatment. Introduce these into your greenhouse, create more humid conditions in the problem area (predatory mites love more humid air), and they will happily eat all the bad bugs in about two weeks. Once there is no food source, they will look for mites elsewhere. They eat nothing else, so these guys are very finicky about their food.
Attacks – Red mites and spider mites only.
Cons – They don’t attack any other pests besides the two types of mites, so if you have other problems, or if the pest is outside, try pirate bugs instead.
Where to buy – Arbico organics sells many different types of predatory mite species, such as Phytoseiulus persimilis.

How to Attract and Keep Beneficial Insects in Your Garden

The problem with these methods is keeping your army well fed, or they will desert. If you do not use pesticides, they will eventually come and lay their eggs upon seeing a delicious infestation of pests. The best way to make your garden look appealing and inviting for your army is the use of nectar-producing plants.

Beneficial insects are called “beneficial” because they do not attack the foliage of our garden plants, vegetables or fruit. Besides eating pests, many feed on the nectar or pollen of flowers. Some species of insects only feed on the nectar as adults – it’s the larvae that eat the bad guys.

Insects that are attracted to nectar-producing plants are:

• Parasitic wasps
• Minute Pirate Bugs
• Lacewings
• Ladybugs

Examples of flowers to entice and help feed your army are:

• Roses
• Marigolds
• Dandelions
• Camellias
• Dill
• Fennel

You likely have a lot of nectar and pollen producing plants already. Best of all, these plants (of course) make your garden more beautiful, attract birds, butterflies and hummingbirds.