Gooseberry Sawfly Larva
Scientific Name: Nematus ribesii
As the name suggests these little pests attack the leaves of goosebery bushes; also
red and white currants, but not blackcurrants - maybe the strong aroma of the leaves puts them off.
The adult female lays its eggs on the underside of the leaves at the centre of the bush. When they
hatch the first instar of the larval stage is very small and makes tiny holes in the leaf. The
next stages are much bigger up to 30mm long, and they cause the most damage, stripping the bush bare as they move outwards.
The early instars make small holes in the leaves.
There can be up to three generations in a season, so the damage can occur anytime
between May and September. The best control is to examine the bushes carefully in late April,
looking for the eggs or the early larval stage low down in the centre of the bush. Repeat in early
June, July and late August when later generations could be starting. Crush any eggs or larvae, and pick off any leaves showing the small holes made by the first instar larvae as they will probably be still there. It
helps to prune the bushes in an open manner or train them as cordons, so that inspection is easy.
They survive the winter as cocoons in the soil around the base of the bush, so clearing away debris
and mulch in the winter and disturbing the soil will allow the birds to find them.
A spray of derris, particularly to the undersides of the leaves when the small larvae are found, and repeated after two weeks, should clear up one generaton. There is no biological control.
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