Over $15 million is spent on pesticides each year in the U.S. alone, with devastating downstream effects for our waterways, ecosystems and soil health. How do ecological gardeners help their green spaces thrive without rampant chemical use?
One essential piece of the puzzle might surprise you...BUGS.
It's not that we want ALL the bugs in our gardens. But we do want to invite beneficial insects to the party. These insects are native to your growing region, and they act as natural predators to garden pests, helping to keep their populations in check without any harmful chemicals or external inputs. A win-win for everyone...except for the aphids, mosquito larvae and other unwelcome guests.
What makes insects beneficial?
Nature is always giving to us through Ecosystem Services. These are the forces, seen and unseen, that flow through Nature, sustaining life on every physical, economic, social and cultural level.
The Insect Biodiversity Center estimates the economic value of ecosystem services provided by insects to be $57 billion USD annually. Insects impact everything from food webs to carbon sinks, and an area's ability to recover after a natural disaster.
Without insects pollinating crops, we don't eat. According to the Insect Biodiversity Center's research,
"Insect pollinators (e.g. bees, flower-flies, and butterflies) pollinate over 85% of wild flowering plants and over 75% of agricultural crop species. The loss of partial or whole insect communities can have disastrous effects for food webs[21, 22] and reduce an area’s ability to recover after disturbances. Many dragonfly species can be biological controls for disease-carrying mosquitoes, and lacewings can control agricultural pests like aphids and mites. Finally, beetles can be highly important for the removal of waste products from the environment, and the introduction of dung beetles onto farms has been shown to promote disease resistance against foodborne pathogens."
What does this mean for your garden?
Inviting more pollinators and pest predators into your landscape is the most ecologically and economically efficient way to help your plants thrive, increase yield, and build healthy habitat for wildlife.
Let's talk about which beneficial insects you want to bring into your space to control common pests, and how to invite them in.
Gardener's Best Insect Friends
Photo: Endangered North American Native 9-Spotted Ladybird Beetle eating aphids, by docentjoyce via Flikr.
#1. Native Ladybugs
A bug by many names, the ladybug, ladybird beetle and lady beetle, this little muncher will eat up to 50 aphids per day and 5,000 in their lifetime. They also eat soft bodied insects, mealybugs, leafhoppers and even ants. When soft-bodied pests are not available, ladybugs may eat some non acidic, sweet fruits. Hosting ladybugs in your garden is more effective than pesticides, with none of the ecological downsides. Also of note: a group of ladybugs is called a loveliness - we are just delighted about that.
How to attract:
- native plants with pollen and nectar, especially yellow flowers
- butterfly weed, coneflower, fern, allium
- mulberry, grape, persimmon, pear, apple, blueberry, cherry, plum, blackberry and raspberry
- if you choose to buy and release ladybugs, be sure they are native and not invasive - the native ones hibernate outdoors for the winter while the asian ladybugs will seek refuge inside your home.
How to keep:
- add or allow small sources of shallow water (good for butterflies too)
- learn what their eggs and larva look like so you can protect them
- don't be afraid of aphids or spray them, that's ladybug food!
- do not use pesticides or herbicides (roundup)
- do not use a "natural" mix like vinegar, soap, salt... this ruins your garden soil and kills plants. Only use these harsh products on areas you don't want anything to grow like bricks, sidewalks, pavers, etc.
#2. Native Wasps
Parasitic wasps sound scary, but they're not harmful to humans, only to pests you don't want! They effectively control aphids and tomato hornworms, among others. Some parasitic wasps do not have stingers, but rather ovipositors - how they lay or "deposit" eggs. While some parasitic wasps do have stingers, most are not aggressive toward humans. The best way to reduce contact between humans and wasps is to give wasps opportunities to build their habitat farther away from heavily trafficked areas. Move wood piles to a more wild corner of your property, rather than stacking it in a path where people often travel.
The potter wasp (pictured above) is one of our native parasitic wasp species in Pennsylvania. Female potter wasps play an essential role in managing caterpillar species, which is a win for gardeners. Curious how they do it? Read more here.
How to attract:
- Queen Anne’s lace, dill, cilantro, and fennel
- Mountain mints, milkweeds, goldenrods, common boneset, rattlesnake master
- Also feed on the nectar of many flowering trees and shrubs
#3. Native Praying Mantis
The Praying Mantis (more properly "mantid") is one of the most easily recognizable insects in general, but do you know if the mantis you're seeing is native or introduced? Mantids are known for their promiscuous eating habits, and introduced mantids pose an aggressive threat to native insects, including the native Carolina mantid. They outcompete native mantids for food, and will even chow down on them.
Garden pests that mantids will help control are leafhoppers, aphids, flies, crickets, grasshoppers, spiders, small tree frogs, lizards, and mice. While it's true that they will also just as happily eat beneficial insects, keep in mind that native mantids have co-evolved with their ecosystem over countless generations. It is good practice to learn to ID introduced mantids and take steps to control their population...we've stomped on non-native oothecas (egg case) with our habitat steward mentors, so don't be afraid to get a little down and dirty in support of native mantids!
How to attract:
- Leave standing stalks from late fall over winter, well into warm weather. Mantids lay their eggs in sacs called ootheca, which they build on standing stalks, such as goldenrod. Nymphs take 3-6 months to develop, and emerge in late spring or early summer.
- Marigolds, dill, fennel.
- Protective, shady plants close to the ground will give them places to hide and roam undetected.
- Water! A shallow bowl with rocks is great so they can hide and sip.
Want to learn more about native plants and garden tips to support beneficial insects? Check out this edition of The Plug by North Creek Nurseries.
We're LadyBug EarthCare, and we empower humans to build habitat and support pollination through Reconnection, Kinship + Stewardship. Want more 1:1 Support and Guidance for your land? → Book a Virtual Site Visit with Kendra