There are several Sawfly species that can attack plants but the most common for gardeners is the Gooseberry Sawfly [ Nematus ribesii ], which targets Gooseberries and sometimes currants. There are three Gooseberry Sawflies; the common Gooseberry Sawfly, the small Gooseberry Sawfly and the Pale Gooseberry Sawfly . They are often mistaken for caterpillars as they are very similar in appearance but are actually part of the Hymenoptera family of insects. Their larvae feed on plants and can strip gooseberry plants of all their leaves, this often leads to a poor crop of Gooseberries.
The common Gooseberry Sawfly larvae can be found from April to June but can also have further generations during July -September. Once the Sawfly larvae are fully developed they stop feeding and will drop into the soil to pupate.
How to control
Disturb the soil aroung Gooseberry bushes to allow birds to feed on the Sawfly pupae and look for Sawfly larvae on plants from April. Remove the first ones observed by hand or start spraying the larvae with Gooseberry Killer nematodes. This provides a safe, natural, chemical free method of controlling the Sawfly. See Gooseberry Sawfly Killer for more details.