Description of the Pest
European fruit lecanium, also known as brown apricot scale, occurs throughout the Central Valley but is rarely an economic problem. The adult female's domed shell is shiny brown, about 0.4 inch (10 mm) 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.
Damage
European fruit lecanium scale produces honeydew as it feeds. Sooty mold may grow on the honeydew, causing blackened areas on leaves and fruit.
Management
Biological control is frequently effective. If treatment is needed, apply oil during dormancy or delayed dormancy which is an effective way to reduce numbers of this pest and is the least disruptive to natural enemies. Numbers of this scale may increase when dormant sprays are omitted.
Biological Control
Fruit lecanium is frequently kept under control by parasitoids including Aphytis spp., Coccophagus spp., Encarsia spp., and Metaphycus spp. and predators including twicestabbed lady beetle and green lacewing.
Organically Acceptable Methods
Use biological control and oil sprays in a certified organic crop.
Monitoring and Treatment Decisions
To determine if a dormant or delayed-dormant oil application is warranted, see Dormant Spur Sample. Look for parasitized scale during 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. Oil spray is required only if 25% or more of spurs are infested with live, healthy scale. Generally, oil, alone, provides control.
If dormant spur sampling indicates a treatment is needed, but a dormant or delayed-dormant timing application was not made, watch for crawlers emerging from underneath the female scale in late May. Apply insecticide such as buprofezin at approximately 50% egg hatch and crawler emergence (when weekly crawler numbers decline from their peak).
Pesticides and Natural Enemy Releases
Not all registered pesticides are listed. The following are ranked by their IPM value, with the most effective and least harmful to natural enemies, honey bees, and the environment listed at the top of the table. When choosing a pesticide, consider information related to water and air quality, resistance management, and the pesticide's properties and application timing. Use PestManage to compare summarized management options for different pests in the same crop. Always carefully read the label of the product being used and take all necessary precautions when handling pesticides.
| Rank | Active ingredient | Example trade name | Group | Group Order | MoA 1 | Amount per acre | REI (hours) ‡ | PHI (days) ‡ | Comments | Selectivity 2 | Bees 3 | Predatory mites 4 | Predators 5 | Parasitoids 5 | Residue duration 6 | Leaching(fish) 7 | Adsorbed runoff(fish) 8 | Solution runoff(fish) 9 | Leaching(human) 10 | Solution runoff(human) 11 | Last updated 12 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
|
Omni Supreme # | Dormant or Delayed-Dormant | 1 |
UNM |
4 gal | 12 | — | Narrow range oil alone can control moder... | broad | low | low | low | none to short | very low | low | very low | very low | very low | 02/2025 | ||
|
|
Omni Supreme # | Spring and Summer | 4 |
UNM |
2% | 12 | — | Narrow range oil used alone will only pr... | broad | low | low | low | none to short | very low | low | very low | very low | very low | 02/2025 |
Legend
- ‡ a b Restricted entry interval (REI) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without personal protective equipment. Preharvest interval (PHI) is the number of days from treatment to harvest. In some cases, the REI exceeds the PHI. The longer of the two intervals is the minimum time that must elapse before harvest.
- # a b Acceptable for use on certified organic crops. Check with your certifier to confirm before application.
- 1 ↩ Group numbers for insecticides and miticides are assigned by the Insecticide Resistance Action Committee (IRAC). Insecticides with unknown modes of action are assigned mode-of-action group numbers (MoAs) that begin with UN. Rotate pesticides with a different mode-of-action group number, and do not use products with the same mode-of-action group number more than twice per season to help prevent the development of resistance. For example, the organophosphates have a group number of 1B; insecticides with a 1B group number should be alternated with insecticides that have a group number other than 1B.
- 2 ↩ Range of insect and mite groups affected by a pesticide. Broad means the pesticide affects most groups of insects and mites; narrow means the pesticide affects only a few specific groups.
- 3 ↩ Risk of harm to honey bees. For more information, see Bee Precaution Pesticide Ratings.
- 4 ↩ Risk of harm to predatory mites. Toxicities are generally to western predatory mite, Galendromus occidentalis. Where differences have been measured in toxicity of the pesticide-resistant strain versus the native strain, these are listed as pesticide-resistant strain or native strain.
- 5 a b Risk of harm to parasitoids and general predators. Toxicities are averages of reported effects and should be used only as a general guide. Actual toxicity of a specific insecticide depends on factors including the application rate, environmental conditions, and the life stage and species of a parasitoid or predator.
- 6 ↩ Length of time residue affects natural enemies. Short means hours to days; moderate means days to 2 weeks; and long means many weeks or months.
- 7 ↩ Risk of harm to fish from leaching, based on USDA Natural Resources Conservation Service Windows Pesticide Screening Tool (WIN-PST).
- 8 ↩ Risk of harm to fish from adsorbed runoff, based on USDA Natural Resources Conservation Service Windows Pesticide Screening Tool (WIN-PST).
- 9 ↩ Risk of harm to fish from solution runoff, based on USDA Natural Resources Conservation Service Windows Pesticide Screening Tool (WIN-PST).
- 10 ↩ Risk of harm to humans from leaching, based on USDA Natural Resources Conservation Service Windows Pesticide Screening Tool (WIN-PST).
- 11 ↩ Risk of harm to humans from solution runoff, based on USDA Natural Resources Conservation Service Windows Pesticide Screening Tool (WIN-PST).
- 12 ↩ Date information was last updated in the UC IPM Pest Management Guidelines.
Important Links
UC IPM Pest Management Guidelines: Prune
UC ANR Publication 3464
F.J.A. Niederholzer, UC Cooperative Extension Sutter/Yuba counties
Acknowledgement for Contributions to Invertebrates
W.O. Reil (emeritus), UC Cooperative Extension Solano and Yolo counties
C. Pickel (emeritus), UC IPM and UC Cooperative Extension Sutter and Yuba counties
W.H. Olson, UC Cooperative Extension Butte County
F.G. Zalom (emeritus), Entomology, UC Davis
R.P. Buchner (emeritus), UC Cooperative Extension Tehama County
R. Krueger, USDA, ARS, Riverside
