What's eating my manzanilla olive?

Manzanilla olives are most seriously damaged by olive fruit fly, which makes the fruit unfit for table use or oil. Olive lace bug bleaches and stipples foliage, and black scale insects coat stems with sticky honeydew. Peacock spot fungal disease (often following pest stress) further weakens trees. Monitor fruit fly from fruit set.

Female lays eggs inside developing olives; larvae feed on the pulp, making fruit unmarketable as table olives and increasing acidity in oil; infested fruit drops or rots. Hang yellow sticky traps and protein-bait traps from June onward to monitor and reduce adults; apply kaolin clay barrier sprays; for organic control, spinosad-baited traps work well.

Feeding on leaf undersides causes silvery-grey stippling and bleaching on upper surfaces; heavy infestations cause premature leaf drop. Apply insecticidal soap or neem oil to the undersides of leaves in spring when nymphs are active; remove weeds that harbour populations around the tree.

Encrusts stems and leaves with hard brown-black shells; excretes copious honeydew that supports sooty mould growth, reducing photosynthesis and fruit quality. Prune to improve airflow and reduce sheltered habitats; apply horticultural oil in late winter or early spring to smother crawlers; encourage natural predators such as parasitic wasps.