Almond lace bug

Monosteira unicostata

1. Identification

• Common name: almond lace bug
• Scientific name: Monosteira unicostata Mulsant & Rey
• Order: Hemiptera
• Family: Tingidae

2. Description of the pest

• Adults: small insects (2.5–3.5 mm), brownish in colour; wings with the lacy appearance typical of lace bugs; flattened body.
• Nymphs: darker in colour, with dorsal spines; they develop on the underside of the leaves.
• Eggs: laid singly or in small groups, generally on the underside of the leaves.

3. Main hosts

• Almond.
• Other rosaceous plants may occasionally be affected, but the pest is mainly associated with almond.

4. Symptoms and damage

• Chlorotic spots on the upper side of the leaves, which develop into yellowish patches.
• Silvery or greyish appearance due to the sucking of sap.
• Presence of dark excrement on the underside of the leaves.
• Reduction of the photosynthetic capacity.
• In severe attacks: premature leaf drop, reduced vigour and decreased production.

5. Biological cycle

• Two to four generations per year, depending on the climate.
• Adults overwinter in natural shelters (cracks, bark, plant remains).
• Activity begins in spring, with egg-laying on the young leaves.
• Rapid nymphal development in hot, dry conditions.
• Populations reach their peak in summer.

6. Monitoring

• Observation of the underside of the leaves for the detection of nymphs and adults.
• Assessment of the presence of chlorotic spots on the upper side.
• Regular sampling in young and mature orchards.
• Intensive monitoring in hot, dry periods, when the pest develops more rapidly.

7. Management measures

• Cultural: removal of plant remains; pruning that favours air circulation; avoiding water stress.
• Biological: natural presence of predators such as lacewings and ladybirds; conservation of beneficials.
• Integrated protection: regular monitoring; intervention only when attack levels justify it; judicious application of authorised insecticides, directed at the underside of the leaves.

Bibliographic references

• EPPO Global Database – Monosteira unicostata.
• CABI Invasive Species Compendium – Monosteira unicostata.
• Alvarado, M. et al. (2003). Biology and damage of Monosteira unicostata in almond orchards.
• Garrido, A. et al. (2010). Tingidae pests in Mediterranean fruit crops.
• Gómez‑Menor, J. et al. (1985). Hemiptera Tingidae of the Iberian Peninsula.