Question: I just read an alarming article about the decline in the insect population. I know that in addition to writing about gardening, you also write about insects. Can you tell me what homeowners like me can do to help insects and slow their decline? Thank you.
Answer: What a wonderful question. I, too, have read several articles citing various studies that have occurred around the world noting the sharp decline in many different insect species. While it may seem overwhelming and one might wonder what difference the “Average Joe” can make from his small backyard, I can assure you that we gardeners are millions strong and the support we can collectively give to a broad diversity of insects is incredibly valuable.
It’s important to first realize that very insect has a job to do, and though it may seem that many of them are hell-bent on destroying the garden, the reality is that less than 1 percent of the million or so identified insect species on the planet are classified as known agricultural or human pests. The vast majority of insects are either benign or beneficial. They’re decomposers, pollinators, predators or they serve some other purpose in the food chain.
It’s also important to understand that just because an insect is an herbivore who might nibble on one of your plants, that doesn’t mean it’s some evil being that should be destroyed. As a whole, gardeners need to learn to be more tolerant of a moderate amount of pest damage.
In my own garden, I’m extremely tolerant because I know that it’s very unusual for a pest insect to outright kill a plant. It might make it look not-so-hot for a few weeks, but it’s not in an insect’s best interest to kill its host plant. That being said, there are certainly a number of introduced exotic insects, like the emerald ash borer, the brown marmorated stink bug and the spotted lanternfly, that should be destroyed because they are not a natural part of our ecosystem and have no natural predators to keep their populations in check.
What can a gardener do?
Sadly, habitat loss, pesticide exposure and several other factors are thought to be leading to the dramatic decline in the populations of many insects.
Creating a safe haven for insects of all sorts is an integral part of today’s responsible gardening. Pollinator gardens and insectary borders offer insects appropriate food sources and year-round habitat. The diversity of insects they attract and support is mind-blowing.
Here are some tips for creating a bug-friendly garden of your own.
Step 1: Start with the right plants
North America is home to some 4000 species of native bees, most of which live solitary lives and are very docile. To support this diverse crew, fill your landscape with pollinator-friendly plants and flowers or create a designated “bee garden”. The area doesn’t have to be huge, but a large, rounded area is generally better at supporting pollinators than smaller, isolated spaces are. Introducing as few as 10 carefully chosen plant species provides a great foundation for an abundance and diversity of pollinators. Include native plants with successive bloom times, varied flower shapes, and assorted coloration for the best results.
Because many other insects aside from our native bees feed on nectar and pollen, it’s also important to have plants for them to feed on as well. These insects often lack the specialized mouthparts of many pollinators, so it’s important to incorporate as many small-flowering plants into your gardens as possible. Members of the carrot family (Apiaceae), such as dill, fennel and Zizia, as well as members of the aster family (Asteraceae), such as Rudbeckia, cosmos, asters, and daisies, are good places to start. Plan for a range of staggered bloom times, capable of generating nectar and pollen from early spring straight through to the first frost.
Step 2: Protect insect habitat — year round!
Some 70 percent of native bees nest in the ground while most of the remaining species nest in tunnels. Allow areas with exposed soil to remain undisturbed and don’t mulch every strip of bare ground, especially south-facing slopes where certain native bees prefer to nest. Tunnel-nesting bee species often take shelter in hollow-stemmed plants and heaps of brush.
Because many other insects also spend the winter “hibernating” in leaf litter or hollow stems, it’s important to allow much of your garden to stand through the winter. Raking up every last leaf, cutting down perennials and pulling out annuals removes much-needed winter habitat for these insects. Do your clean-up chores in the mid- to late spring, when the temperatures are regularly in the 50s, instead of in the fall.
Step 3: Eliminate all pesticides
Insects of all sorts are susceptible to the effects of pesticides, not just the insect you are targeting. In fact, in an alarming amount of situations, pesticide applications have far more collateral damage than you might assume.
Not only are insects exposed to pesticides through direct physical contact, but also through the consumption of contaminated nectar and/or prey. And, don’t get me started on systemic pesticides. Common grub-killers put on the lawn, as well as other systemic pesticides, are carried within the vascular tissue of plants where they travel through the “veins” of the plant to all parts, including into the pollen and nectar. And they don’t just travel in the vascular tissues of the plant onto which they were applied; they’re also absorbed by any plant whose roots are growing nearby.
For example, using a systemic grub-killer on the lawn means that chemical is also being absorbed into nearby trees, shrubs and perennials, where it makes its way into the nectar and pollen. When a bee consumes that nectar, they also consume the systemic pesticide. These pesticides also end up working their way up the food chain and affecting larger insects and animals, too.
Step 4: Support insects through your buying decisions
When possible, support small, local, organic farmers who work hard to not only provide food that’s free from synthetic pesticides, fertilizers and herbicides, but also often have insect habitat present on their farms. Avoid processed foods that contain GMO ingredients as these foods are heavily sprayed with various pesticides and herbicides that may affect non-target insects. Buy local, organically grown cut flowers, instead of flowers grown by farms halfway around the world whose pesticide use is unknown. Buy products from companies who give a percentage of their profits to organizations that support wildlife, or who have organic gardens, green roofs or wild spaces in their office parks and business centers. Be a smart, insect-friendly shopper whenever possible