Identifying Garden Pests and Bugs in Ontario

One of the most popular pages on this blog continues to be the Weed identification page posted in May, so I decided it would be a good idea to follow it up with a pest ID post for those of you out there who are finding bugs and bite marks in your garden and wondering who did what.

I’ll start off with the good guys, the bugs we’re happy to have around and want to support. The most famous among these is the ladybug, whose adult form we can all recognize easily: red shell and black spots representing how old they are….or at least that’s what someone told me they meant in elementary school! Some important things to know about ladybugs though are:

Ladybug Eggs

Their eggs look like this. If you see these eggs on the undersides of leaves, don’t destroy them, and in 2-5 days you’ll find….

Ladybug Larvae

…these guys! Now, even though they look like a troublemaking alligator-insect hybrid they are ladybug larvae, and are even more useful to have around than adult ladybugs because they have a voracious appetite for aphids.

 Attract ladybugs by planting pollen and nectar flowers, dill, dandelion, queen anne’s lace and yarrow are all favourites.

Some more bugs that look like pests but are actually beneficial predators and plants that specially attract some of them:

Soldier Beetle

Soldier Bugs

eat aphids, caterpillars, corn rootworms, grasshopper eggs, beetle larvae

attract with goldenrod, hydrangea, catnip, milkweed and wild parsley



eat soil dwelling pests; slugs, worms and fly pupae



eat aphids, thrips, mealybugs, scales, moth eggs, caterpillars and mites

attract with pollen and nectar flowers and flowering weeds

Assassin Bug

Assassin Bugs

eat general pests, flies, mosquitoes, beetles, caterpillars

Now that you’re familiar with some of the beneficial insects in the garden, let’s discuss some more damaging ones. We’ve gone into flea beetles and leafminers  in  previous posts, and some methods to deal with them, though now that we’re further into the season I would definitely say they aren’t worth stressing about, they are an season pest who prey upon young leaves, but as long as the infestation isn’t severe enough to kill your seedlings they’re not worth much concern.

Aphids Everywhere!

Aphids are one of the top garden pests, they’re so small and so annoying and basically suck the life force right out of plants so are the bane of many a gardener’s existence. Luckily all that rage has led to a great deal of knowledge about these pests. They can be dealt with by attracting beneficial insects like those above, and by planting strongly scented deterrents such as anise, basil, chive, catnip, coriander, garlic, stinging nettle or trap crops like yellow nasturtium and sunflowers. If aphid infestation is severe, they can be killed by spraying with a strong, direct stream of water, or managed using a tomato leaf spray.

Imported Cabbageworm!

Imported Cabbageworms are the bane of my personal existence. I spent months in Vancouver picking them and their eggs off of cabbages, broccoli and cauliflower, and it made me determined to get them in their egg state as much as possible. These are the caterpillar form of those white moths you see everywhere in spring and summer, and they love members of the brassica family. They will lay their eggs within the grooves of the leaves and plant heads, and they hatch releasing caterpillars who chew large holes through the leaves. Beneficials are a great way to deal with these pests, and garlic or hot pepper sprays can also help. The best approach is just to be vigilant, however, keeping a close eye on the undersides of brassica leaves, and considering planting red or purple varieties to make the bugs easier to spot.

More pests posts will come soon! In the meanwhile, feel free to ask about any pest damage you’ve encountered, and I’ll try to get to the bottom of it!


Filed under Companion Planting, Pest Management

2 responses to “Identifying Garden Pests and Bugs in Ontario

  1. sue Robinson

    I have a problem, I only noticed today on my pussywillow. I haven’t been able to identify the bug in question. It has a teal head and copper body, like a miniture beetle. It’s wrecked complete havoc, they seemed to be mating and eating at the same time, eating the whole leaf, and leaving only the skeleton of the leaf behind.. Any help you could provide would be helpful.

  2. Wendy

    I planted my front lawn with bugle weed this spring, and now I find they are infested with alot of red bugs. They start out as very small very bright red bugs then grow into a flat mostly black with red outline on their wings, look sort of like an assasin bug. They do not seem to eat the bugle weed but seem to live in the plants and are all over the front of my house. What type of bug is this and should I be controlling the population?

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