rose slug on rose leaf

Coiled roseslug on a rose leaf.

Updated: April 21, 2021

Key points

  • The roseslug sawfly is one of three common sawflies that attack roses (others are curled and bristly roseslugs).
  • Adults of all three species resemble wasps and are about 1/4" long.
  • Mature larvae look like caterpillars, but they are not. They are about 1/2" long and yellow-green with yellow heads.
  • The larvae skeletonize the leaves and in heavy infestations can cause leaves to turn brown and curl.
  • Check roses in May and June (in Maryland) for the slug-like, greenish-yellow larvae on the under surface of skeletonized leaves.
  • However, roseslugs can be active through the fall.
  • If the infestation is light, pick off and destroy the larvae.
  • To control heavy infestations, use horticultural oil or spray with spinosad. Target the undersides of the leaves.
  • Control is the same for all three species.

Bristly roseslug larvae are about 5/8" long and greenish white with long, stout bristles. They skeletonize leaves by feeding from the undersides of the leaves and later chew holes through the leaves.

Curled roseslug larvae are metallic green above, marked with white dots, grayish white underneath, with yellow-brown heads. They curl up like a cutworm and are about 3/4" when mature. Curled roseslugs initially feed by skeletonizing the leaves, but eventually defoliate entire leaflets except for the largest veins.

 

 

roseslug on rose bud and damage
Roseslug larvae on damage on bud 
defoliated rose stem
Defoliated rose stem

Rev. 2020