Social pear sawfly

The social pear sawfly has orange caterpillar like larvae that feed on leaves in groups within webbing on pears, hawthorn and cherries.

Social pear sawfly larvae in web on flowering cherry

Social pear sawfly larvae in web on flowering cherry

Quick facts

Common name Social pear sawfly
Scientific name Neurotoma saltuum
Plants affected Pear, hawthorn, cherries
Main symptoms Orange caterpillar like larvae and webbing
Most active June to July

What is social pear sawfly?

Sawflies are in the same group of insects as bees, ants and wasps (the Hymenoptera). They have caterpillar like larvae that feed on plants the adults are winged insects that can appear fly-like.

Social pear sawfly has orange caterpillar-like larvae that reach 25mm (1in) in length. The larvae feed on leaves in groups within webbing which can cover entire branches. Most often seen on pear, it will also feed on hawthorn, cherry, medlar, plum and cotoneaster. Hawthorn and cotoneaster can also be affected by caterpillars of the hawthorn webber and prorphy knothorn moth, these have small brown caterpillars and also produce webbing.

The adult is a 14mm (½in) long black winged insect. 

Symptoms

Webbing on leaves and branches of pear and some other plants containing pale orange caterpillar like larvae. Leaves within the webbing are consumed.

Control

Social pear sawfly is rarely abundant and control measures are not usually necessary and this insect can be tolerated.

Non-pesticide control

If necessary it is often possible to deal with social pear sawfly by pruning out the affected part of the tree and disposing of the larvae.

Pesticide control

Pesticide control of this insect is not necessary as it is unlikely to affect the health of the trees it affects and if necessary the ‘nests’ can be pruned out.

Biology

There is one generation of social pear sawfly a year. Eggs are laid on foliage in May and June. The orange caterpillar-like larvae are found during June and early July. They feed in groups within webbing and reach 25mm long when fully grown. When the larvae have completed their feeding they go down into the soil where they pupate and emerge as adults in the following spring.


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