University of Maryland Extension

Sawflies - Trees and Shrubs

dusky birch sawfly on leaf
Dusky birch sawfly and damage

Also see redheaded pine sawflies (a pest of mugo pine)

Sawflies resemble caterpillars but have more than 5 pairs of prolegs on the abdomen. Common examples include blackheaded ash sawfly, dogwood sawfly, and dusky birch sawfly (see above photo). Sawflies often have shiny red or black heads 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. 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. Heavy infestations of young larvae may be sprayed with a horticultural oil.

blackheaded ash sawfly larvae
Blackheaded ash sawfly

coiled dogwood sawfly
Dogwood sawfly

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

butternut woollyworm adult
Butternut woollyworm adult on leaf
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