How to Manage Pests
UC Pest Management Guidelines
The olive psyllid can be found in San Diego and Orange Counties. Olive psyllid feeds on olive, Russian olive (Elaeagnus angustifolia) and mock privet (Phillyrea latifolia).
Light green and tan adults are 2.5 mm long and strong jumpers. In olive they don’t move very far, leading to clumped distributions. Forewings are marked with a few small dark spots. Nymphs are flat, green to tan, and secrete a white waxy coating that covers the entire colony. There are five nymphal stages (0.4 mm to 1.5 mm long). The eggs are elliptical, 0.3 mm long, pale yellow, and attach to the substrate by a pedicel.
Depending on temperatures, with 68° to 77°F being optimal, a psyllid can grow from egg to adult in 3 months. There are three generations per year starting in March/April. Females lay one or more eggs on the new shoots, with a single female able to lay 1000 eggs or more. The second generation develops on buds and flowers in May/June. The third generation is often unnoticed, appearing in September/October. Adults overwinter in sheltered areas of the olive trunk.
In warm temperatures (above 80°F), psyllids become inactive. Mortality may occur at temperatures above 90°F.
Trees that are heavily infested can have yield losses of 30 to 60%. The olive psyllid damages trees through direct feeding on buds, flowers, tender shoots, and small fruit and also through the production of honeydew, which increases sooty mold development. During olive flowering and fruiting, psyllid waxy secretions cause flower and small fruit drop and yield reductions. Large populations may retard the growth of young trees.
Even though the second generation causes the most damage, reduce numbers during the first generation before psyllids secrete their heavy waxy coating, which protects them from pesticides.
Monitoring and Treatment Decisions
UC IPM Pest Management Guidelines: Olive