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 inch 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.
Biological control and oil sprays are organically
Monitoring and Treatment Decisions
To determine if a dormant or
delayed dormant treatment is warranted, see DORMANT SPUR SAMPLING. Record results on a monitoring form . 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.
||Amount to Use**
choosing a pesticide, consider information relating to impact on natural enemies and honey bees, impact 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#
||MODE OF ACTION: Contact including smothering and barrier effects.
Oil alone can control moderate populations of soft scales. Oil applications
at this time may cause some young shoots to burn or die back, especially in
years when trees are water-stressed, or have recently been subjected to
freezing temperatures or to dry winds. Dormant flowable emulsion is less
likely to cause burn. The Moyer variety is highly susceptible to oil injury;
delaying the oil spray until late Feb. to March 1 will reduce oil burn. Not all oils are organically acceptable; be sure to check individual products.
UC IPM Pest Management Guidelines: Prune
UC ANR Publication 3464
Insects and Mites
C. Pickel, UC IPM Program, Sutter/Yuba counties
F. J. A. Niederholzer, UC Cooperative Extension, Sutter/Yuba counties
W. H. Olson, UC Cooperative Extension, Butte County
F. G. Zalom, Entomology, UC Davis
R. P. Buchner, UC Cooperative Extension, Tehama County
W. H. Krueger, UC Cooperative Extension, Glenn County
Acknowledgment for contributions to Insects and Mites:
W. O. Reil, UC Cooperative Extension Solano/Yolo counties
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