GROUND BEETLES TO THE RESCUE
“Most people see them walking along the sidewalk and they want to step on them, because it’s a big beetle, and they go crunch. I wish people would not do that,” says entomologist and Olds College instructor Kenneth Fry.
“And what’s fascinating is that in the spring you can go outside at night and all of a sudden you hear this rustling of the leaves and you wonder, what’s going on? Have I got snakes? No! That’s the ground beetles emerging from winter and moving around in the understory in the garden through the leaf litter, the dried leaves. And they make quite the racket. It’s almost spooky.”
Fry says several types of ground beetles are found naturally in Calgary gardens where they eat slugs, snails, maggots, weevil larva and all kinds of caterpillars from the coolest spring days through to late fall. And if you have insect problems in the garden such as root maggots or slugs, you probably have a ground beetle shortage because they are voracious. And while ground beetles make that gratifying “crunch” when stepped on, each death means you lose a buddy, a helper, in the garden.
So ground beetles clean up your garden and work on your behalf getting rid of the pests you fear. How do we get more of these little creatures working for us? Step 1: Remember these insects are friends, not foe. There is no need to “control” them as they are working on your behalf to control your pests. “Both larval and adult ground beetles are predators of insects and other arthropods, earthworms and slugs,” says Fry in his book Garden Bugs of Alberta, and “the adults live two to three years.” Chemicals like Sevin are listed to control these beetles but the question is why apply chemicals to kill something working to help you get rid of true pests?
Step 2: Remove landscape fabric. “They are evening hunters. They pupate in the soil and the adults emerge from their pupal cell in the soil and they hunt above ground. They can even climb up into trees. The larvae are the ones in the soil.” Having a layer of fabric or plastic between where the adults or pupae winter and where the adults feed on plants and in leaves is a problem.
“The adults know when things are waking up from the winter. The trouble is the ground under fabric or plastic slowly dies because insects can’t move up into the garden or move back down into the soil,” says Fry.
Adding barriers between the soil and the life above means beneficial ground beetles won’t crawl into the ground to sleep the days away or hibernate over winter. Instead, they’ll move away to gardens with leaves on the soil surface and a barrier-free banquet of insect goodies in and on the soil surface. Undisturbed soil is best for these beetles so avoid fabric barriers and allow some areas of your garden to go natural.
Step 3: Avoid insect-damaging products.
Mechanical products sold as “safe” and “simple” include Diatomaceous earth. The trouble is, DE doesn’t discriminate and kills all insects. Chemical products like Sevin, a commonly available insecticide, “kills on contact and lasts in the soil for three months,” according to the website. All insecticides, natural or otherwise, are dangerous to beneficial bugs.
Step 4: Use garden products that are beetle friendly. This means organic fertilizers, mulches, leaves left on the ground, and a varied and mixed landscape to provide the widest food source for hungry beetles. Products like compost, alfalfa pellets, liquid fish fertilizer and kelp meal offer minerals without damaging the environment so are safe for everything including beetles.
Step 5: Protect and don’t step on ground beetles. Watch for them crossing sidewalks and moving about the garden in the evening. Shelter or protect ground beetles while they go about their business — eating pests in your garden.
It’s hard to preserve and protect everything in our lives but with a little care and attention, you can find and help ground beetles that are so busy helping us. Sometimes people ask me how to control one pest or another but the real question is how to nurture insects that help us control pests. The answer is simple: attract and protect ground beetles and you are well on your way.
Donna Balzer is a horticulturist, author and speaker. To hear her latest podcasts or read the blog, connect with her at donnabalzer.com