The larvae of sawflies can cause severe damage to leaves; some species can defoliate plants in a matter of days. The larvae are generally green, up to 3cm (1 1/4 in) long and tend to look somewhat like caterpillars. However, Solomon's seal sawfly larvae are about 2 in (3/4 in) long, a grey-white colour and have black heads, whilst the gooseberry sawfly larvae have distinct black spotting. Most larvae grip the leaf edge and wave their bodies in an 'S' shape when they are disturbed.

Sawflies often lay their eggs towards the centre of bushes and plants, so when the larvae hatch out they are well concealed. They then eat their way outwards, which means that they may only be noticed once the damage has been done.

Control

The key to controlling most outbreaks of sawfly larvae is to catch them early and treat the problem as a matter of urgency. Check plants regularly, particularly near the centre of the bushes where most of the eggs are laid. Where possible, remove by hand, or treat serious infestations with pyrethrum, permethrin, fenitrothion, pirimiphos-methyl or malathion.