For a truly ‘green’ garden, forget sprays and try natural predators

06/14/2014 12:00 AM

06/14/2014 6:32 PM

Every month during the growing season I receive a package of Fly Predators in the mail. Inside are hundreds of tiny bugs the size of gnats that prey on fly larvae. I scatter them in my horse corrals and where the dogs do their business to reduce the summer fly population naturally.

This is an example of biological control that is ideal for chicken coops, compost piles and a dozen other problem areas without using chemicals and time-consuming sprays.

You might not have heard of Fly Predators, but you probably know about ladybugs. These popular little red beetles were the first successful bio-control for combating aphids in residential gardens. The predator-prey relationship keeps insect populations in balance naturally.

In the past, the cure for all bug problems was to douse the plant with pesticide. This not only kills the problem bugs, it kills the predator bugs, too. When bug populations are destroyed by pesticides, the predator-prey balance goes out the window. New bugs that either escaped the pesticide or just flew in are free to reproduce prodigiously in the absence of predators. This is the reason we see huge insect infestations in some gardens while they rarely occur in organic ones.

To understand how this relates to your summer garden, consider the predator-prey relationship of ladybugs and aphids. Known as “plant lice,” aphids are sucking pests that gather on the soft tips of new growth to feed and breed. Their most dangerous predator: the ladybug. Yes, these little red beetles are ferocious consumers of aphids. With a big ladybug presence in your yard, the aphids never gain a foothold.

Another important predator is the praying mantis. These large, green bugs are voracious feeders that consume all sorts of insects that prey on your plants. They hatch from curious hard egg cases laid on tree bark, walls, shrubs and other less-conventional surfaces. This insect does not have a larval stage, but instead hatches out dozens of nymphs, which are tiny versions of the adult. These nymphs will inhabit your summer garden as they mature by feeding on anything they can catch.

There are other bugs you can buy to add more diversity to your predator population:

• Green lacewing is a heavy feeder that loves the eggs of a wide range of pests, including thrips, mealy bugs and whiteflies.
• The Trichogramma wasp loves to lay her eggs into those of tomato hornworms and other insects just like fly predators do. When the wasp larvae hatch, they immediately begin feeding on the developing grub. Soon, a new crop of predator wasps emerges from the remains of what would have been a damaging caterpillar.

For anyone who needs help keeping bugs at bay in an organic garden, there’s a way to boost your predator bug population while having fun with the kids. Purchase live ladybugs, which are carried at some nurseries and home stores, and are also available online. Introduce the ladybugs to your yard, where they’ll go directly to the bad bugs and start feeding.

Bringing live predator bugs into your garden is a great way to wow the kids. Just pour ladybugs into their small hands and let them spread the love down your rows and borders.

This is the essence of a truly “green” garden where we can work with Nature herself to harness the age-old dance of predator and prey to keep your plants pest-free.

Maureen Gilmer is an author, horticulturist and landscape designer. Learn more at Contact her at or P.O. Box 891, Morongo Valley, CA 92256.

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