Pest profile

Dogwood Sawfly

Macremphytus tarsatus · Hymenoptera: Tenthredinidae[3]

Dogwood sawfly larvae feed in groups on dogwood leaves and change looks as they grow, from white and waxy, like bird droppings, to cream with black spots and finally yellow and black; full-grown larvae may bore into soft wood to overwinter.[1][2]

Cluster of dogwood sawfly larvae, yellow with black markings, curled on a dogwood leaf
Cluster of dogwood sawfly larvae, yellow with black markings, curled on a dogwood leaf. (c) Dan Vickers, some rights reserved (CC BY) — via iNaturalist, CC BY 4.0

How to identify it

  • Adults are slender, shiny black, wasp-like sawflies.[1]
  • Young larvae are covered in a white waxy material; larvae and their shed skins may resemble bird droppings.[1][2]
  • Older larvae are pale cream with black spots, and full-grown larvae are about an inch long and yellow and black.[1][2]

Where it lives

NC State and UMass Extension both report it on dogwoods; there is one generation a year.[1][2]

Biology and life cycle

Adults emerge from May to July; females insert up to 100 or more eggs in groups on leaf undersides, often along the veins, each egg making a small bump that turns brown.[1][2]

Larvae feed in groups, first skeletonizing leaves, then eating everything but the midrib.[1][2]

Full-grown larvae wander to find decaying or soft wood, including logs, landscape timbers and even lawn furniture, where they make cells to overwinter and pupate in spring.[1][2]

Damage and signs

  • Dogwoods, especially gray dogwood, appear to be the only hosts, and group feeding can cause considerable defoliation.[1][2]

Health risk

None to people or pets.[1][2]

Control

Traps and physical control

Shake small larvae from the plant and crush them.[1]

Pesticides

If defoliation warrants it, insecticidal soap or horticultural oil works as long as larvae are under an inch long; older larvae are very tough.[1]

Common questions

What are the white waxy worms eating my dogwood leaves?
Young dogwood sawfly larvae, which later turn cream with black spots and then yellow and black.[1][2]
How many generations of dogwood sawfly are there?
One a year; adults emerge from late May to July.[1][2]
Why are larvae boring into my deck or landscape timbers?
Full-grown dogwood sawfly larvae tunnel into soft or decaying wood to spend the winter.[1][2]

Sources

  1. NC State Extension, “Dogwood Sawfly (PDIC Factsheet).” content.ces.ncsu.edu/dogwood-sawfly (accessed 2026-10-15)
  2. UMass Extension Landscape, Nursery and Urban Forestry Program (Landscape Insect & Mite Guide), “Macremphytus tarsatus (Dogwood Sawfly).” www.umass.edu/agriculture-food-environment/landscape/publications-resources/insect-mite-guide/macremphytus-tarsatus (accessed 2026-10-15)
  3. iNaturalist, “Macremphytus tarsatus taxon page (order and family).” www.inaturalist.org/taxa/143431 (accessed 2026-10-06)

Updated 2026-10-15. Built from sourced records. Spot an error? Tell us.