What's eating my picual olive?

Picual olive, Spain's most widely grown oil variety, faces the same core threats as all Olea europaea: olive fruit fly larvae ruin the oil content and flesh, black scale coats stems with honeydew, and olive moth caterpillars eat flowers and bore into fruit. Picual's high polyphenol content gives some resistance but does not eliminate fruit fly risk.

Eggs laid inside the olive hatch into larvae that consume the pulp; infested fruit develops secondary bacterial rot and drops early, cutting oil yield and quality. Use mass-trapping protein bait stations and yellow sticky traps from fruit set; apply kaolin clay coating every 2–3 weeks; harvest early when infestation pressure is high.

Three overlapping generations damage flowers (spring), bore into seeds (summer), and mine leaves (autumn/winter); the fruit-boring generation causes the most direct crop loss. Monitor with pheromone traps; apply Bt at egg-hatch during the phytophagous (fruit-boring) generation in summer; encourage parasitic wasps by minimising broad-spectrum sprays.

Heavy encrustation on stems reduces sap flow; honeydew supports sooty mould, blocking light and contaminating harvested olives. Prune to open the canopy; apply horticultural oil or insecticidal soap targeting the crawler stage in late spring; biological control agents are effective in warm regions.