Pest management is a big part of maintaining your garden – in many cases, this involves insects. Before you can prevent or remediate insect damage, you need to differentiate the good bugs from the bad bugs. For context, less than 10% of all insects in the world are considered as pests to gardeners – it just sometimes feels like all of them are in your garden!
In this article, we want to look more specifically at some of the bugs you’ll find in your garden.
Are all bugs pests? Of course, the answer is no, as most bugs are either neutral or good. Good bugs help your garden in several ways, including:
- Eating the actual pests
- Pollinating flowers on your vegetable plants
- Aerating the soil beneath your plants
- Decomposing plant waste in the soil, making it available to plants
It’s essential to tell the difference between the good bugs and bad ones to avoid hurting the good ones when dealing with the bad ones. For example, often, when you hit a bad bug with diatomaceous earth or horticultural oil, you end up hurting the good bugs at the same time. So, be sure of which bugs you are attacking.
To identify whether a bug is good or bad, the first step is finding out what it is. There are various apps for this (such as iNaturalist or Seek), websites (e.g. https://www.insectidentification.org/), and gardener forums that can identify bugs if you send a picture. It takes some work to find and identify a particular bug, but this is a good investment of time as you’ll probably see the same bugs every year.
If you prefer not to look up each bug, you can instead monitor the plants around the bugs for damage. Just be careful as good bugs such as ants and ladybugs are often found near plants with stunted growth – not because they caused it but because they are attracted to aphids, which are often the real culprit.
Here are sample lists of good and bad bugs commonly found in Ontario gardens.
Some of the Good Bugs:
- Ants – aerate the soil, do some pollination, and eat pests for you
- Bees – pollinate many of your flowering vegetables
- Dragonflies – eat pests for you
- Green lacewings – eat pests for you
- Ground beetles (not including beetles that live on your plants, those are bad) – eat pests for you
- Ladybugs – eat pests for you
- Parasitic wasps – lay eggs on many pests; the wasp larvae then feed on the pest
- Spiders – eat pests for you
- Spined soldier bugs (be careful as they look like squash bugs) – eat pests for you
Some of the Bad Bugs:
- Aphids – weaken plants by sucking the sap from them and leave a trail of honeydew which can attract sooty mould
- Beet leafminers – eggs hatch inside the leaves of beet, chard and spinach plants, and the larvae tunnel for food within the leaves
- Cabbage moths – the green caterpillar larvae strip the foliage of plants in the cabbage family
- Cutworms – the adult form of many grubs, these bugs eat the stems of young vegetable plants, literally chopping them down
- Earwigs – nest inside plants such as lettuce and cabbages and also eat the foliage
- Flea beetles – feed on the foliage of brassicas
- Pepper flies – lay eggs inside of peppers in late July, after which the larvae feed on the inside of the peppers, causing them to rot
- Potato bugs – feed on the foliage of potato, eggplant, and tomato plants
- Slugs and snails – strip the foliage of leafy plants
- Squash bugs – weaken squash family plants by sucking sap from them
- Thrips – weaken plants by sucking the sap from them
- Tomato hornworms – strip the foliage of tomato plants
- Whiteflies – weaken plants by sucking the sap from them
These are just sample lists, but they include many of the good and bad bugs that you will see in Ontario. Once you know which bugs you are dealing with, they become much easier to manage. Better yet, they become much easier to avoid in the first place using ideal plant choices, crop rotation and companion planting. You can refer to other HomesteadTO newsletters and articles on pest management or join our Grow Veggies program to learn more about tried and true solutions to pest prevention and management at our teaching farm.
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