Hosts:

European fruit lecanium has a very wide host range including many deciduous trees and shrubs. Elm and stone fruits (Prunus) are the most common hosts.

Damage and Diagnosis:

European fruit lecanium is a soft scale that feeds on the phloem of small branches. Under sustained outbreaks they are capable of causing decline and dieback, but generally are under a high level of natural control which largely prevents any significant injury. European fruit lecanium is also capable of producing large amounts of honeydew, which can be a serious nuisance problem and favor the growth of sooty mold.

Coinfestations with other scales can occur, particularly mixed populations with European elm scale. The European elm scale can be identified by having a covering that is dome-shaped, dark brown, and fairly smooth. Life History and Habits: The European fruit lecanium spends the winter as a second instar nymphs on the twigs, appearing as a small, raised lump about 1/4-inch diameter. They continue growing in spring, molt to the adult stage and develop rapidly. Most feeding, honeydew production, and injury occurs at this time.

The body of the female swells with eggs during late spring. Males may be produced and mating occur at this time but European elm scale often reproduces asexually. The eggs hatch underneath the body of the mother scale, and the crawlers move out continuously for several weeks in midsummer during favorable weather. The mother scale then dies, after having produce several hundred eggs. The newly hatched crawlers move to feed on leaves for the remainder of the growing season. Prior to leaf fall the pale-brown Instar II scales return to the twigs for winter.

Management:

Although a common and widespread insect, serious, sustained outbreaks of this species are rare, presumably due to natural controls. Parasitic wasps are one of the more commonly observed natural enemies of this insect. Applied controls, including dormant oils, are similar to those used for other soft scales.

The information herein is supplied with the understanding that no discrimination is intended and that listing of commercial products, necessary to this guide, implies no endorsement by the authors or the Extension Services of Nebraska, Colorado, Wyoming or Montana. Criticism of products or equipment not listed is neither implied nor intended. Due to constantly changing labels, laws and regulations, the Extension Services can assume no liability for the suggested use of chemicals contained herein. Pesticides must be applied legally complying with all label directions and precautions on the pesticide container and any supplemental labeling and rules of state and federal pesticide regulatory agencies. State rules and regulations and special pesticide use allowances may vary from state to state: contact your State Department of Agriculture for the rules, regulations and allowances applicable in your state and locality.