The garden is a place full of insects of all kinds. From those we encourage — the butterflies and honey bees — to those we dread, that can destroy our blooms and impact our harvests. Somewhere in between are the beneficial insects and the predatory ones that are good for our gardens and help keep the pest insects under control. Below we’ll cover some of the less desirable garden inhabitants and what you can do to minimize their impacts.
Aphids are tiny, soft-bodied, pear-shaped insects that typically feed on younger growth (buds, new shoots, flowers) of plants like roses, sweet peas, and tropical plants. They can be green, yellowish, white, brown, or black. As they suck the sap out of plants, they create a sticky substance that can sometimes attract other bugs, like ants. Aphids multiply very quickly and you’ll usually find a large group of them.
Thankfully, minor infestations might be handled by some of their natural predators: ladybugs, assassin bugs, predatory wasps, and lacewings. I happened to have aphids on my sweet peas (though not causing much damage) and was relocating a ladybug over to them, when I spotted a lacewing perched nearby – hooray! You can also hose aphids off of your plants with a strong stream of water, repeating as needed. Another option is to spray them with an easy DIY insecticidal soap – just use a few teaspoons of liquid dish soap per quart of water, and be sure to get the undersides of the leaves. If these don’t work, you can look for a systemic insecticide. One ingredient you might see is called imidacloprid, and will kill aphids when ingested but won’t harm pollinators like bees, hummingbirds, and butterflies.
Oriental and Japanese Beetles
Yes, there are TWO gobblers. The Oriental beetles have a mottled brown appearance and often appear a little earlier than the Japanese beetles, which have the typical shiny green and bronze you might think of. These beetles are often responsible for holes in leaves and nibbled flowers. You may find them hiding between flower petals, particularly on pale-colored flowers. I find them on my pink, yellow, and white dahlias, daisies, and white coneflower.
While you could apply sprays for beetles, lure traps and removal by hand are very effective. I have a trap that uses a lure with a bag below it. They come toward the lure, fall into the bag, and that’s the end of them. If you use one of these, make sure to place it downwind of your flowers, or the scent will drift across your flower beds and attract them.
I also do regular rounds through the garden with a jar of soapy water in hand. I use a small mason jar with a generous squirt of dish soap and maybe ½ cup of water – a pretty high concentration, with the level low in the jar so they can’t climb out. These guys are typically slow moving, so it’s easy to knock them in.
These beetles are small (maybe ¼” long) and typically found on cucumbers and some squash and melon plants. (They seem to like my delicata squash, unfortunately, and also favor canteloupe.) I find the type with yellow and black stripes in my garden, but they can be spotted as well. The tricky part about these is not just that they like to feed on your plants (adults feed on both foliage and fruit while larvae can feed on roots), but that they carry bacteria that causes bacterial wilt. This will cause the leaves to wilt and appear to dry out as it shrivels up. Unfortunately, you cannot save an infected plant.
I’ve found that cucumber beetles are skittish and quick to fly, so trying to squish them or knock them into soapy water is more difficult than some of the other bugs. However, they are attracted to yellow (like the squash flowers), so yellow sticky traps can catch them.
These look similar to stink bugs, but they’re not the same. You’ll probably spot stink bugs (which are a little bit wider and rounder) inside your home as you’re pulling out your holiday decorations. They also look similar to a “good bug” group — the assassin bugs. Assassin bugs are predatory insects that feed on other insects, like aphids, leafhoppers, and caterpillars.
Squash bugs, as you might expect, target things like pumpkins, zucchini, and winter squash, as well as melons. They inject toxins into plants and suck moisture out of the leaves, causing them to wilt, blacken, dry up, and turn brittle. They can fly, but you’ll typically find them walking around, often on the undersides of leaves. Adults lay groups of eggs under the leaves, which hatch into tiny nymphs that change color as they grow and age.
Pesticides aren’t typically effective on the adults, so the easiest way to keep them under control is to pick them off. This is where that jar of soapy water comes in handy again. The eggs can be scraped off of the leaves (you can crush them or toss them on the ground where other beetles will snack on them). If I find a leaf with a group of young bugs that I missed, I tend to just remove and dispose of the entire thing rather than trying to chase them all.
Squash vine borers
Unlike the other insects mentioned so far, these are actually a moth! They tend to avoid cucumbers and melons, but like squash, pumpkins, and zucchini. The adults lay eggs at the base of the stem and the larvae (which look like grubs) bore into the stem and eat it from inside as they grow. When the grub is inside, you’ll see a grainy-textured, sawdust like orange debris outside the hole.
Squash vine borer eggs are tiny, flat, oval, and brown, and laid near the base of the stem. Personally, I’ve never spotted them! I have removed the larvae successfully, though. If you spot an entry point, use a thin, sharp blade to slit the stem up one side lengthwise (in the direction of the growth, rather than across). The borer larva will have a fat, white, wrinkled body and brown head like a grub and can grow to about an inch long. They are easily removed and eliminated. Thankfully, there is typically just one generation in our area, and my plants have been able to pull through surgery just fine! I have also been able to find and squish some adults. For future seasons, clean up and remove all debris in the fall. The borers will overwinter in the soil, so try to move squash plants to different areas from year to year.
I always called these pincher bugs, thanks to their appearance, but the ‘earwig’ name is quite unappealing. It comes from an old myth that they would crawl into your ear — don’t worry, they won’t. Earwigs tend to feed on younger sprouts of plants (I often find them in the petals of a bloom) as well as decaying materials. They are attracted to moisture, cover (areas of fallen leaves, etc), and a good food source. You can eliminate hiding places by cleaning up old leaves and spent flowers that may fall in your garden beds. You can also knock these into your soapy water jar when you’re on patrol.
These are just the “regulars” I find in my garden. Of course, there are always others that can do damage — cutworms, slugs, hornworms, white flies, scarlet lily beetles, thrips, even grasshoppers! To find out more about common garden insect pests, check out the Farmer’s Almanac resources or contact your local extension office. As a general note – if you need to use a pesticide, try to choose one that has low impact on the “good guys.” Neem is plant-based and prevents insects from feeding, which eventually kills them. Pyrethrin (which you may see listed on a label) doesn’t leave a residue and treatments need to come in contact with the beetles to be effective, so they will have fewer unintended effects. Good luck, and go get your soapy water ready!