European fruit lecanium scale

Parthenolecanium corni

European fruit lecanium is a scale insect that is also known as the brown apricot scale. The adult female's domed shell is shiny brown and about 0.4 inch in diameter. Adult females are mostly found on 1- to 3-year-old wood on the underside of woody canes, cordons, and spurs where they remain for the rest of their lives. Females reproduce parthenogenetically (without mating), and eggs are laid in spring (beginning in April) beneath the female's body. Crawlers hatch from May through most of June. They move to the shoots and leaves of the current season's growth and molt to second instars from June to July.
In the North Coast a portion of the second–instar population continues development and becomes adults that produce a second generation. The crawlers of the second generation may be found on leaf petioles and shoots in August. Beginning in September, second-instar nymphs from both the first and second generation migrate back to 1- to 3-year-old wood. They overwinter under the bark in the second-instar stage. Early in spring, the second instars molt to the third-instar stage and then quickly develop into mature females that begin laying eggs in April and May. There is usually only one generation each year, but a portion of the population in the North Coast will have two generations. The second generation has not been observed in other grape-growing regions.

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