How to identify and manage apple sawfly

UK seasonality and monitoring

Adults lay eggs around blossom time in spring.

During this period inspect Apples, concentrating on the crop stage and plant parts described above. Note when and where fresh injury appears; old feeding marks can remain after the pest has moved on.

Crops and plants affected

The recorded hosts are Apples. This list identifies plants worth checking; it does not mean every crop is equally vulnerable. Start with the listed plants and inspect the tissue where this pest feeds.

Check affected crops for these signs: Corky scars, winding grooves and premature fruit drop. Match the symptom to a live pest, larva, egg or characteristic feeding sign before deciding that treatment is needed.

Damage and likely consequences

Corky scars, winding grooves and premature fruit drop. A small amount of old damage on a vigorous plant may be cosmetic. Continued feeding on roots, seedlings, growing points or edible parts can reduce establishment or yield.

On Apples, judge severity by checking whether injury is fresh and spreading, whether the plant is still growing, and whether the edible part is affected. Avoid removing a crop based on one ambiguous mark.

Prevention

Monitor blossom clusters and collect fallen fruitlets during the June drop.

Control and integrated management

Cut a damaged fruitlet open to look for a winding gallery and larva, then remove confirmed affected fruitlets.

Natural predators and wildlife-conscious choices

Encourage birds and beneficial insects; tolerate minor scarring.

For apple sawfly on Apples, use a barrier or hand removal only where it fits the crop and life stage. Keep any cover taut, inspect it for trapped wildlife, and remove it when protection is no longer needed.

Long-term management

Inspect young apples shortly after blossom next spring and tolerate minor scarring where fruit remains usable.

For apple sawfly on Apples, record the bed, crop stage and date when fresh damage first appears. Those notes help time protection and monitoring before the same crop stage is vulnerable next season.

Common mistakes

A symptom alone is not a diagnosis. The adult sawfly is small and wasp-like. The young larva enters an apple fruitlet and leaves a winding, corky scar; affected fruitlets may drop. A single damaged fruit is not enough to diagnose a widespread problem. Look for a matching live pest or fresh feeding sign before intervening.

Early winding scars in fruitlets are more consistent with sawfly than the later codling-moth tunnel.

If damage continues

Recheck Apples where new injury is appearing, including the hidden feeding site: roots, folded leaves, leaf undersides, flowers or fruit as appropriate. If identification remains uncertain, photograph a live specimen alongside the damage and ask an allotment association or horticultural adviser.

If the recommended control (Pick damaged fruitlets and maintain orchard hygiene.) has not helped, confirm that it was fitted or applied at the right crop stage and that fresh damage is still occurring. Old marks do not heal when the pest has gone.

Frequently asked questions