If your tree and shrub leaves look like green lace in the middle of summer, Japanese beetles are a likely culprit. They're one of the most visible — and most frustrating — summer pests in southern Ontario gardens.
What they do
Adult Japanese beetles are metallic green-and-copper, about a centimetre long, and they feed in groups through the warm months. They skeletonize leaves — chewing the soft tissue between the veins and leaving a lacy skeleton behind. They're not picky: linden, birch, maple, fruit trees, roses and many shrubs are all on the menu.
- Lacy, skeletonized leaves, usually starting at the top of the plant.
- Clusters of beetles feeding together on warm, sunny days.
- Browning of heavily fed foliage later in the season.
How much should you worry?
Here's the reassuring part: on an established, healthy tree, Japanese beetle damage usually looks far worse than it is. A mature tree can lose a surprising amount of leaf area in late summer and recover fine the next spring, because the damage comes late in the growing season. The real concern is on young, newly planted or already-stressed trees and shrubs, where heavy feeding adds to an existing burden.
On a big healthy tree, Japanese beetles are mostly an eyesore. On a young or stressed one, they're a stress you don't want stacked on the others.
When to get help
If beetles are hammering young trees or valued ornamentals year after year, it's worth a conversation about timing and treatment options. Get in touch and we'll help you decide whether your trees need intervention or just a bit of patience until the season ends.