University of Maryland Extension

Sawflies - Trees and Shrubs

dusky birch sawfly on leaf
Dusky birch sawfly and damage

Key Points

  • Also, see redheaded pine sawflies (a pest of mugo pine)
  • Sawflies resemble caterpillars but the are not. Sawfly larvae have more than 5 pairs of prolegs on the abdomen. Common examples include black-headed ash sawfly, dogwood sawfly, and dusky birch sawfly (see above photo).
  • Sawflies often have shiny red or blackheads and the bodies often have black spots or stripes, and are 2 to 1 inch long.
  • They like to feed in groups and many may be found together feeding on a branch (called gregarious behavior).
  • In light infestations, damage may appear as defoliation on needles of individual branches or shoots.

Management

  • Heavy infestations may cause complete defoliation of conifers.
  • Manually removing and destroying the sawflies may control light infestations. They usually are closely gathered together feeding in the same area of the plant. 
  • Heavy infestations of young larvae may be sprayed with a horticultural oil.

blackheaded ash sawfly larvae
Blackheaded ash sawfly

dogwood sawfly life stages
Dogwood sawfly

larvae of butternut woollyworm
Butternut woollyworm sawfly larvae
found on black walnut

butternut woollyworm adult
Butternut woollyworm adult on leaf
Photo: Lacy L. Hyche, Auburn University, Bugwood.org

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