Good Bugs or Bad Bugs: What Gardeners Need to Know

Hands up if you’re the type of gardener that automatically squishes or swats insects away when you see them in your outdoor space. We thought so! But did you know that of the one million identified insect species, entomologists estimate that just one per cent are classified as known agricultural or human pests? The rest are harmless or even beneficial – some predator bugs take care of the pests that DO want to ruin your flowerbeds! We asked Savvy Gardening’s Jessica Walliser, a horticulturist, radio host and author of Attracting Beneficial Bugs to Your Garden and Good Bug Bad Bug to help us figure it all out.

Why do we think insects are harmful and how should gardeners embrace the role that insects have in our outdoor space?

It’s unfortunate that such a small percentage of “bad” insects affects our perception of the entire insect world. So much time, energy, and money is spent battling these “bad” insects when if we would just switch our focus to promoting and encouraging the “good” insects, the garden would have a much better balance. A natural cycle of predator and prey exists in every ecosystem –including our gardens – and when we step in with a spray bottle we’re disturbing that natural cycle and inserting ourselves where we don’t really belong.

It’s important to let the “good” predatory bugs have the chance to bring pest numbers under control before we gardeners take any action ourselves. Give the good bugs time to do their thing, learn what they look like and how they work, and encourage them to make a home in your landscape. In my own garden, I haven’t sprayed any pesticides – organic or otherwise – in over 15 years. I have an excellent population of predatory insects that keep my pest numbers in check, and I know it’s very rare for a pest to outright kill a plant so I’m tolerant of a bit of plant damage. After all, it’s not in the pest’s best interest to kill the host plant for themselves and future generations.

What are some other common myths about insects?

When I speak to groups and show even long-time gardeners photos and videos of predatory insects in action, they are often incredibly surprised at what these insects look like and how they work in the garden. People who have gardened their entire lives often don’t know what a larval ladybug or lacewing looks like or how tiny some species of parasitic wasps really are. Most gardeners say they never see any good bugs in their garden and so they don’t think they’re there, but more often than not, these gardeners just don’t know what to look for. People are also often surprised to hear that many of the common bugs they see in their gardens are actually predators. Paper wasps, fireflies, dragonflies, tachinid flies, and spiders are spied in gardens all the time, but most folks don’t know that these common insects are incredible at helping us control everything from slugs and aphids to squash bugs and cabbageworms. 

What are the best ways to identify and deal with bugs?

Always identify an insect prior to taking any action against it, since most aren’t harming your plants in any way. Keep an eye on the insect for a few minutes and watch what it’s doing very carefully. If it’s just sitting on a leaf or a flower and not taking a bite out of it or sucking out plant juices, there’s a good chance it’s either benign or beneficial. If you do see it munching on a leaf, take a photo of the insect and use a good insect ID book or website to find an exact match. If you don’t have a good ID book, sometimes simply typing in something like “yellow beetle with black stripes on pumpkin plant” will bring you to a proper ID after comparing the photos you find online. Then, do some research to find out what the insect is all about and whether or not it’s something worth worrying about.

Which beneficial insects have you seen in your garden?


All photos courtesy of Jessica Walliser.

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