Dec 5, 2008
Raspberry sawfly, Monophadnoides geniculatus, is an uncommon pest in raspberries on the Central Coast of California. I recently had a question concerning this pest, so it something worth discussing.
Raspberry sawflies are not flies, but actually wasps. The larvae, since they are fixed on the leaves and damage them, draw our attention as pests. Larvae are usually found on leaf undersides, are ½ of an inch long, light green in color, and have a brown stripe down the back. Larvae generally occur in groups, so a closely spaced group of punctures and holes in the leaves should be a signal to look for raspberry sawfly.
Being very mobile, the adults are seen far less. The adult wasps are flattish and have a thick body roughly ¼ of an inch long. Female adults also have a yellow white band across the back of the abdomen.
In almost all cases, sawflies do not merit control, since in a light to moderate infestation, sawfly larvae will make a few holes in the leaves and not compromise fruit yield. However, more severe infestations, of the sort that we have not yet seen on the Central Coast, have the potential of eating all the leaves and seriously damaging the plant.
Probably the most important point of this writing is that growers do not confuse raspberry sawfly larvae with more damaging moth larvae, since chemicals used to control them can be different.
