Leafcutting bee
Megachile spp.
63 host plants
Last updated
Leafcutting bees create distinctive, precise semicircular cuts along the edges of leaves on ornamental plants and shade trees during late spring and summer. The bees use the cut leaf pieces to line their nesting tunnels; affected leaves show obvious, clean-edged cutouts that are unmistakable. The damage is entirely harmless to plants and indicates that native pollinators are active in your landscape.
No control is necessary or desirable for leafcutting bees since they are beneficial native pollinators that increase productivity. Appreciate their presence as a sign of a healthy, pollinator-friendly landscape. If leaf cutting is extreme on valuable ornamentals, provide alternative host plants like roses or shrubs. Leave nesting sites available such as dead wood or hollow stems.
Quick Reference
Adults cut circular to semicircular holes in leaf margins and flower petals to use as nesting material. Damage is cosmetic and harmless to otherwise healthy plants.
Cultural Controls
- Cover preferred small plants with cheesecloth or screening when leaf cutting is first observed. Remove barriers about midsummer when adults are no longer active.
- Reduce nesting sites by filling holes 1/8 to 7/8 inch in diameter.
- Seal the ends of pruned rose canes with wax or white glue to prevent nesting.
- Healthy plants easily tolerate cosmetic leaf damage; no treatment needed in most cases.
- Leafcutting bees are important pollinators and should not be killed. Avoid pesticide use near these beneficial insects.
- Neonicotinoids (clothianidin, imidacloprid) are documented as toxic to megachilid bees; avoid use on bee-visited plants.
Host Plants (63)
Sources & References
Primary: UC IPM
- OSU PNW 692 — Megachilid bees in the Pacific Northwest (
- PNW Insect Management Handbook
- WSU HortSense