How to Manage Pests
UC Pest Management Guidelines
European Fruit Lecanium
Scientific Name: Parthenolecanium corni
(Reviewed 6/10, updated 6/10, pesticides updated 9/15)
In this Guideline:
Description of the Pest
European fruit lecanium, also known as the brown apricot scale, occurs throughout the Central Valley, but is rarely a problem. The adult female's domed shell is shiny brown, about 0.4 inches in diameter. Eggs are laid in spring and hatch from May to July. The young develop through the remainder of the season and overwinter on twigs and small branches as partly grown crawlers. There is one generation each year.
The chief injury is the production of honeydew that, in large amounts, can damage leaves and fruit. Sooty mold growing in the honeydew can cause blackened areas on leaves and fruit.
Biological control is frequently effective; if treatment is needed, oil applied during dormancy or delayed dormancy is an effective way to reduce populations of this pest and the least disruptive of natural enemies. Increased populations of this scale may appear when dormant sprays are omitted.
Fruit lecanium is frequently kept under control by parasites including Aphytis spp., Coccophagus spp., Encarsia spp., and Metaphycus spp. and predators including lady beetles and lacewings. If present, ants will interfere with biological control; note their presence when monitoring.
Organically Acceptable Methods
Biological control and certain oil sprays are organically acceptable methods.
Monitoring and Treatment Decisions
To determine if a dormant or delayed-dormant treatment is warranted, follow sampling and treatment threshold guidelines in DORMANT SHOOT SAMPLING. Look for parasitized scale during the summer by lifting up scale covers as well as examining the covers for exit holes. If a large number of scales are parasitized, treatment may not be needed during the following dormant season.
UC IPM Pest Management Guidelines: Nectarine
Insects and Mites
K. R. Day, UC Cooperative Extension, Tulare County
Acknowledgment for contributions to Insects and Mites:W. J. Bentley, UC IPM Program, Kearney Agricultural Center, Parlier
R. E. Rice, Kearney Agricultural Center, Parlier