5 Pests Found In Spring Gardens

As the snow melts and Toronto gardeners eagerly head to their backyards, there are insects waking up from their winter slumber. The arrival of spring in Southern Ontario brings a specific cast of characters that can turn a budding garden into a snack bar.

Here is a guide to the most common spring pests in Toronto and how to manage them sustainably. Visit our garden plants and flowers that deter pests article to learn more about the different garden plants and flowers that help prevent pests.

1. The Early Invaders: Aphids

Often the first to arrive, aphids are tiny, pear-shaped insects that cluster on new, succulent growth. They use needle-like mouthparts to suck sap, causing leaves to curl and yellow. In Toronto, they are particularly fond of rose bushes and young vegetable starts.

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• The Toronto Sign: Look for "honeydew" a sticky substance they excrete that often attracts ants and can lead to black sooty mould.

• Management: A sharp blast of water from a garden hose is often enough to dislodge them. You can also encourage local "beneficials" (insects that are beneficial to gardeners) like ladybugs and lacewings by planting dill or yarrow nearby.

2. The Boxwood Bandit: Box Tree Moth

Toronto is currently at the "epicentre" of a North American infestation of this invasive species. If you have boxwood hedges (popular in many GTA front yards), you need to be vigilant in late April and May.

• The Box Tree Moth Sign: Look for "webbing" between boxwood leaves and bright green caterpillars with black stripes. They can defoliate a hedge in days.

• Management: Use BTK (Bacillus thuringiensis kurstaki), a biological insecticide widely available at Toronto garden centres. It is safe for humans and pets but lethal to these caterpillars.

3. The Scarlet Menace: Lily Leaf Beetle

For those growing true lilies (Lilium species) or Fritillaries, this bright red beetle is a formidable foe. They emerge from the soil as soon as the first lily tips poke through the ground.

• The Lily Leaf Beetle Sign: You’ll see the adult beetles (vibrant red with black legs) or their larvae, which look like disgusting "blobs" of black mud (actually their own excrement) on the underside of leaves.

• Management: Hand-picking is the most effective method in early spring. Check your lilies on the first warm days of April. If you see the red adults, squish them immediately.

4. The Night Feeders: Slugs and Snails

Toronto’s damp spring mornings are the perfect environment for slugs. They are particularly destructive to Hostas which are a staple in Toronto’s many shaded gardens.

• Slug and snail Sign: Ragged holes in the middle of leaves and shimmering "slime trails" left behind on the soil or foliage.

• Management: Use copper tape around pots or create "beer traps" (shallow dishes of beer buried at soil level). For a long-term fix, Diatomaceous Earth (DE) sprinkled around vulnerable plants works by dehydrating them.
  

5. Lawn Disruptors: White Grubs

If you notice your lawn looks like it’s been "peeled back" or if skunks and raccoons are digging up your yard in May, you likely have a grub problem. These are the larvae of Japanese Beetles or June Beetles.

• White Grub Sign: Patches of dead, brown grass that lift up easily like a piece of carpet.

• Management: Late spring is the time to plan for beneficial nematodes. These microscopic organisms are applied to the soil to hunt down the grubs. Ensure the soil is moist and the ground has warmed up before application (usually late May in Toronto).

Pro-Tips for Toronto Gardeners

- Use the "Dormant Spray" Window

Before buds fully open in early spring (March/early April), many Toronto pros use a Dormant Spray kit (Horticultural Oil and Lime Sulphur). This coats overwintering eggs of scale, mites, and aphids on fruit trees and shrubs, suffocating them before they wake up.

- Companion Planting

Toronto's urban environment benefits greatly from biodiversity. Interplanting your vegetables with Marigolds, Garlic, and Onions can help deter beetles and aphids naturally.

- Support the "Good" insects

Avoid broad-spectrum pesticides that kill everything. Instead, foster a habitat for:

• Ladybugs: Eat aphids and mites.
  
• Praying Mantis: General predators often found in GTA gardens.‍
• Pollinators: Be careful with sprays when bees are active on spring blooms like Forsythia and Lilacs.