hymenopus coronata

Conrad Bérubé
island crop management
email: uc779(at)freenet.victoria.bc.ca

Insect info

aphid life cycle
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San Jose Scale

Information on this page is derived from public domain documents published by the federal government of canada, the provincial government of British Columbia and information contributed on electronic discussion groups. Please bear in mind that any pesticides mentioned in these pages may no longer be recommended or registered for the indicated use — check with your local pesticide officer or regional agrologist for current info (you can use the provincial directory on the internet to search for those job titles or call Enquiry bc at 1 800 663-7867 for assistance). It is recommended that you use a search engine using the common name and/or scientific name of the organism(s) below, together with the name of your province, to find biology and management information relevant to your local conditions.

If you choose to use chemical controls remember to
always follow pesticide label instructions!

insects of economic importance in Canada and British Columbia

family: diaspididae
species: quadraspidiotus perniciosus
common names: san jose scale
notes: Gluthion will kill the natural enemy fauna

Damaged Fruit      Damaged Fruit

San Jose Scale Life Cycle Agriculture and Agri-Food Canada Insect Identification Sheet No. 38 March 1981

San Jose Scale

Quadraspidiotus pemiciosus (Comstock)

The San Jose scale is a major pest of fruit trees in British Columbia and Nova Scotia, and in southern Ontario and Quebec. It is also found on many bush fruits and shrubs, and on some shade and forest trees.


A heavily infested tree will lack vigor and its foliage will be thin and yellow-speckled. If the infestation is not checked, the tree will die. San Jose scales appear as small, disk-shaped specks on the bark; if a hand lens is

used, a raised nipple-shaped spot can be seen at the center of each disk. Often the bark around the scales is reddened. In appearance, a heavily infested tree looks as though it had been sprinkled with wood ashes when wet. The fruit may also be attacked, usually near the blossom and stem ends. On the fruit, the insects appear as gray patches, each surrounded by an inflamed red area.

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Life History:

The insect overwinters on the bark in the first nymphal, or sooty black, stage. With the resumption of the sap flow in the spring, the insect begins to grow and is usually fully grown by the time the trees come into bloom. Females are covered by scales that are nearly round and about 2 mm across; the waxy covering of the males is oval-shaped and about 1 mm across. The females remain under their scales throughout their lives.

Damaged Fruit       San Jose Scale

In late May or early June, the males begin to emerge and mate with the females which give birth to living young. These usually appear in the latter part of June and are most numerous on the upper branches. Resembling very small yellow mites or lice, the young insects move about on the bark or fruit for about a day after birth and then begin to feed on the sap. In molting, the growing insects lose their legs and antennae, but remain attached to the feeding surface by their sucking mouth parts. As each insect continues to grow, a waxy secretion is given off by its body and this hardens into the protective scale under which it lives. In southern Ontario, there may be two or three generations a year. Dry, hot seasons favor the increase of this insect.


Spray with a superior oil (70 sec. viscosity) in the spring while the trees are still dormant. Do not spray during the bloom period. A post-bloom spray consisting of a contact residual insecticide should be used to control the pest in its crawling stage. For information on the control of this insect consult
your provincial Department of Agriculture.

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Copyright © 2007 Conrad Bérubé, site design, concept and scripting. All rights reserved worldwide.
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