Sawflies - Trees and Shrubs

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

Dogwood sawfly

Butternut woollyworm sawfly larvae
found on black walnut

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