How to Manage Pests
UC Pest Management Guidelines
European Fruit Lecanium
Scientific Name: Parthenolecanium corni
In this Guideline:
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
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
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
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.
|When choosing a pesticide, consider
information relating to impact on natural enemies and
of the timing on beneficials,
and environmental impact. Not all registered pesticides are listed.
Always read label of product being used.
||DORMANT OIL such as:
||DORMANT FLOWABLE EMULSION
||NARROW RANGE OIL (440 or higher)#
||MODE OF ACTION: Contact including smothering and barrier effects.
||COMMENTS: Choose a narrow range oil with a
50% distillation point of 440 or higher for dormant season use. Always check
with your certifier as to which oils are organically acceptable. Oil alone can control moderate populations of soft scales.
UC IPM Pest Management Guidelines: Nectarine
UC ANR Publication 3451
Insects and Mites
W. J. Bentley, UC IPM Program, Kearney Agricultural Center, Parlier
K. R. Day, UC Cooperative Extension, Tulare County
Acknowledgment for contributions to Insects and Mites:
R. E. Rice, Kearney Agricultural Center, Parlier
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