How to Manage Pests

UC Pest Management Guidelines

DESCRIPTION OF THE PEST

The European fruit lecanium, also known as the brown apricot scale, occurs throughout California, but is rarely a problem. This scale has one generation a year. It overwinters as a nymph on twigs and small branches. In spring, it grows rapidly and secretes large amounts of honeydew. The adult cover is domed, shiny brown, and about 0.25 inch in diameter with several ridges along the back. After mating in late spring, the females lay many eggs, filling the entire space beneath the covers, and die after egg production.

DAMAGE

The European fruit lecanium sucks juices from leaves and twigs. Low to moderate populations apparently are not damaging, but heavy populations reduce terminal growth and vigor. The chief injury is the production of large amounts of honeydew. Sooty mold growing on the honeydew can cause blackened areas on leaves and fruit.

MANAGEMENT

Biological control is frequently effective; if treatment is needed, oil applied during dormancy or delayed dormancy is the most effective way to reduce populations of this pest and the least disruptive of biological control.

Biological Control
Many natural enemies help to control populations of European fruit lecanium. Common predators include lady beetles (Chilocorus orbus spp., Rhyzobius lophanthae), lacewings, the predaceous sap beetle (Cybocephalus californicus) and predatory seed bugs (Phytocoris spp.). Parasites include Aphytis spp., Coccophagus spp., Encarsia spp., and Metaphycus spp. Frequently, scales found during the growing season are heavily parasitized.

Monitoring and Treatment Decisions
Apply treatments during the dormant or delayed dormant period before rapid scale growth begins in early spring. High scale populations often result from the use of chemicals that are disruptive to parasites and predators. If a high degree of parasitization is observed, treatments may be delayed until late spring after crawlers emerge. Treat during dormant or delayed dormant period if scale population or sooty mold was observed the previous year.

Common name		Amount to Use**		P.H.I.+
(trade name)		(conc.)	(dilute)	(days)
The following materials are listed in order of usefulness in an IPM program, taking into account efficacy and impact on natural enemies and honey bees. When choosing a pesticide, also consider information relating to environmental impact.
DORMANT or DELAYED DORMANT
A.	NARROW RANGE OIL#	4 gal	1.5 gal
	MODE OF ACTION: Contact including smothering and barrier effects.
	COMMENTS: Oil alone can control moderate populations of soft scales. Not all oils are organically acceptable; be sure to check individual products.
B.	NARROW RANGE OIL	4–8 gal	1.5–2 gal
	. . . PLUS . . .
	DIAZINON* 50WP	4 lb	1.25 lb
	MODE OF ACTION: Contact including smothering and barrier effects.
	COMMENTS: Organophosphate insecticides used during delayed dormancy are very toxic to honey bees. Remove bees from orchard if cover crops or weeds are in bloom. Oil sprays may injure trees that are water stressed. It is advisable to postpone an oil application to water-stressed trees until winter rains have replenished soil water and the tree bark is noticeably moist. Avoid drift and runoff into surface water or choose alternative materials. Diazinon has been found in surface waters at levels that violate federal and state water quality standards.
	. . . OR . . .
	CHLORPYRIFOS*
	(Lorsban) 4EC	2 qt	0.5 qt
	MODE OF ACTION: An organophosphate (Group 1B)1 insecticide.
	COMMENTS: Apply before blossoms open or injury may occur. Do not graze livestock in treated areas or feed them treated cover crops. Avoid drift and runoff into surface water or choose alternative materials. Chlorpyrifos has been found in surface waters at levels that violate federal and state water quality standards.
	. . . OR . . .
	PYRIPROXYFEN
	(Esteem) 0.86 EC	13–16 fl oz	3.25–4 fl oz
	(Seize) 35WP	4–5 oz	1–1.25 oz
	MODE OF ACTION: An insect growth regulator (Group 7C)1 insecticide.
	COMMENTS: An insect growth regulator that targets egg hatch. Good coverage is essential for good control. Use allowed under a supplemental label.
	**  For concentrate applications, use the amount given in 80–100 gal water/acre, or lower if the label allows; for dilute applications, amount is per 100 gal water to be applied in 300–400 gal water/acre, according to label. * Permit required from county agricultural commissioner for purchase or use. 1 Modes of action are important in preventing the development of resistance to pesticides. Rotate chemicals 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. For example, the organophosphates have a group number of 1B; chemicals with a 1B group number should be alternated with chemicals that have a group number other than 1B. Mode of action is assigned by IRAC (Insecticide Resistance Action Committee). For additional information, see their Web site at http://www.irac-online.org/.

PUBLICATION

UC IPM Pest Management Guidelines: Cherry
UC ANR Publication 3440
Insects and Mites
R. A. Van Steenwyk, Insect Biology, UC Berkeley
K. M. Daane, Kearney Agricultural Center, Parlier
J. A. Grant, UC Cooperative Extension, San Joaquin County

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