Encyclopedia Article

Description of sawflies

Sawflies are wasps.  They don’t look like wasps (in the minds of most people).  They look like fat-bodied flies without the pinched waist that is characteristic of the better-known wasps.  Sawflies have four wings, while all of the true flies have only two.  Sawfly wasps cannot sting.

Life cycle of sawflies

Sawflies got their name from their ovipositor – the egg-laying apparatus at the end of the female’s abdomen.  When the female is ready to lay eggs she uses the ovipositor to saw a slit in a leaf, needle or stem.  Eggs are then deposited into the slit.

All ants, bees, wasps and sawflies have a complete life cycle of four stages, egg, larva, pupa and adult.  The larva is a worm-like immature that eats and grows until it forms a pupa and transforms to the adult stage (the way a caterpillar changes into a butterfly).

Damage of sawflies

Sawfly wasp larvae are plant eaters.  Most resemble caterpillars in general appearance and also in damage.  Many sawflies are plant pests that cause noticeable-to-destructive loss of plant foliage.   Sawflies are host-plant specific; that is each different species of sawfly feeds on a specific host plant and does not move from one plant type to another.  For example, the European pine sawfly larvae are gray-green larvae with shiny black heads that live in clusters and eat pine tree needles in May; they will not feed on other plants.  Similarly the dogwood sawfly larvae that eat entire leaves from gray and red osier dogwood plants in late summer will be found only on dogwood shrubs.

Management of sawflies