Maryland Grows

Boonsboro, MD – 

Ladybugs.
Lacewings.
Ground beetles.
Wasps.

What do all these insects have in common?  They are the good guys, the beneficial insects that help keep bad bugs at bay in our gardens. 

Nine out of 10 insects are beneficial. Yes, most of those flying, crawling, buzzing and burrowing bugs out there are actually helping you battle the few nasty bugs that harm plants. 

How? Some are predators that eat bad bugs.  Others are parasites that lay eggs on bad bugs so their babies get fed. 

So instead of reaching for that spray bottle when you see a bug ambling across your petunias, pause.  Is it harming the plant?  Or is a good guy just moseying by? 

Think before you squish or spray.  When you take out good bugs, you’re taking out your allies. 

Instead, send me a photo or bring me a sample so I can identify the insect and suggest controls if needed.  Let’s work together to keep – and build – your army of helpful insects. 

To know beneficial insects is to love them.  So let’s meet a few.  

The ladybug is the good bug poster child.  It happily dines on thousands of aphids in its lifetime as well as scale, spider mites, whiteflies and more. 

Lacewings are beautiful lacy-winged (hence the name) insects.  They may look delicate, but are voracious hunters that eat many different dastardly bugs. 

Some wasps are parasitic, laying their eggs on harmful insects.  There is even one called the scoliid wasp that lays its eggs on Japanese beetle grubs in the soil. 

Other generalist predators like praying mantids and assassin bugs stalk and eat a wide variety of insects – good and bad – to keep their populations balanced.  

I’m betting that now that you’ve met a few beneficial insects, you’d like to know how to attract more to your yard.   Here are a few tips. 

First, give them the basics: food, water and shelter. 

Many insects need pollen and nectar.  So make sure something is blooming from spring through frost to provide both food and shelter.  Native plants support native insects best.

Many beneficial insects are small, risking life and limb to sip water from a traditional birdbath.  So put water in shallow containers. A pot saucer will do. 

Some plants are better at attracting beneficial insects than others. Herbs with their tiny flowers are sized just right for pint-sized beneficials.  

Daisy-shaped flowers such as coneflowers and zinnias are magnets for good bugs as are plants with umbrella-shaped flower clusters such as yarrow and dill. 

One of the best things you can do for beneficial insects is to stop or limit your use of chemical insecticides. Chemicals don’t discriminate, killing both good and bad bugs.  

This doesn’t mean you can’t control garden pests.  I’m just suggesting a kinder gentler approach.  

Insecticidal soap, horticultural oil and Bt – the holy trinity of organic controls – manage most bad bugs.  Add cultural practices such as handpicking, row covers and crop rotation and you have an arsenal of crackerjack controls. 

Don’t let bugs bug you.  Most are friends.  Embrace them.  Encourage them.  And deal swiftly with the few bad bugs with organic controls.  They work. 

_{Annette Cormany, horticulture educator, University of Maryland Extension – Washington County}