European Fruit Lecanium

family: coccidae
species: Parthenolecanium (=Lecanium) corni
common names: european fruit lecanium
antennae characters: none
hosts:
natural enemies: scale predatory beetles, lindorus lophanthus, and scale parasites, metaphycus helvolus
notes:

Agriculture and Agri-Food Canada Insect Identification Sheet No. 39 March 1981

Lecanium Scale

Parthenolecanium (=Lecanium) spp.

Lecanium scales are common pests of many fruit trees and brambles throughout Canada. In Ontario, they are primarily pests of plum, especially the Japanese varieties, while in British Columbia, apricots and peaches are the hardest hit. In Canada there are five different species, almost indistinguishable in habit and appearance.

Injury:

Scales feed by sucking the plant juices of host species. When infestation is severe twigs and branches may be killed, plants stunted in growth and leaves turned yellow and curled. Fruit produced is often undersized and may fall prematurely. In addition, the scales produce large quantities of honeydew that drip onto fruit. A black mold grows on the honeydew and renders the fruit unmarketable.

Life History:

Lecanium scales overwinter in the second nymphal stage on host branches, and mature the following spring. Adult lecanium scales are hemispherical, reaching an average of 6 mm in diameter at maturity. Their coloration varies tremendously from host plant to plant, although older scales tend to be a shiny brown. In late May or early June, hundreds of small white eggs are laid beneath the body of the female. At the end of June or in early July the eggs hatch; the young scales migrate out from under the mother and establish themselves on the undersides of leaves to feed. Immature scales are spindle shaped, flat and about I to 1.5 mm long. In August, they migrate back to the twigs to complete their growth and overwinter. There is a single generation per year.

Pest Management:

If infestation is heavy, spraying may be necessary. Timing is very important, as trees should be sprayed just after the eggs have hatched. Contact your provincial department of agriculture for further information.