Plum sawfly

Hoplocampa minuta and Hoplocampa flava

1. Identification

• Common name: Plum sawfly
• Scientific name: Hoplocampa minuta Christ and Hoplocampa flava L.
• Order: Hymenoptera
• Family: Tenthredinidae

2. Pest description

• Small adults (4–6 mm), yellowish-brown or dark body.
• Transparent wings with the venation typical of the Tenthredinidae.
• Whitish to light green larvae, resembling small caterpillars.
• Larvae feed inside the young fruit.
• Pupation in the soil, in resistant cocoons.

3. Main hosts

• Plum tree (main host).
• Other species of Prunus may be affected.
• Damage is more frequent in traditional and low-intervention orchards.

4. Symptoms and damage

• Punctures in the young fruit shortly after petal fall.
• Fruit with internal galleries and gum exudation.
• Premature fruit drop (“maggoty fruit”).
• Significant reduction in effective fruit set.
• More severe damage in years of abundant flowering.

5. Biological cycle

• One generation per year.
• Adults emerge in spring, coinciding with plum flowering.
• Oviposition in flowers or newly formed fruit.
• Larvae develop inside the fruit for 3–4 weeks.
• Pupation in the soil during summer and winter.
• Emergence synchronised with the start of the next flowering.

6. Monitoring

• Observation of flowers and young fruit after petal fall.
• Fruit sampling to detect larval galleries.
• White or yellow traps to capture adults during flowering.
• Recording of flowering dates to predict adult emergence.
• Annual monitoring to assess risk and the need for intervention.

7. Management measures

• Cultural: shallow tillage of the soil in winter to expose pupae, removal of attacked fruit and proper canopy management to reduce favourable microclimates.
• Biological: conservation of natural enemies, application of entomopathogens to the soil and promotion of specific parasitoids when present.
• Integrated protection: monitoring during flowering, use of traps for early detection, targeted treatments only at the critical post-flowering moment and integration of cultural practices to reduce the annual population.

Bibliographic references

• EPPO Global Database – Hoplocampa spp..
• CABI Invasive Species Compendium – Hoplocampa minuta and H. flava.
• Blommers, L. H. M. et al. (2003). Biology and control of sawflies in stone fruits.
• Cross, J. V. et al. (1999). Pests of stone fruit in temperate regions.