Pear Sawfly Larva
Location: Calgary, AB
Date: July 5,  2004
       Photo 1

Pear Sawfly Larva on Cotoneaster

Common Name:  Pear Sawfly Larva or Pear Slug

Latin Name:  Caliroa cerasi  (Linnaeus 1758)
                        (R. Bercha, det.)

Length:  11 - 12 mm

Range:  Throughout Alberta

Habitat:  Various

Time of year seen:  June - September (Additional Sightings)

Host Plants: Cotoneaster, pin cherry, mountain ash,
                       hawthorn and plum

Other: Although the Pear Sawfly was originally native to Europe it now has a global distribution due to the movement of infested goods.  In North America the species is parthenogenic.  The female adult flies emerge from mid-June to July and oviposite eggs into the bottom of the host plants leaves.  In about 2 weeks the larva hatch and begin feeding on the lower and upper surfaces of the leaf, which they skeletonize, leaving only the veins.  Over a period of 3 weeks the larva pass through 6 or 7 instars before falling to the ground where they pupate in a cocoon of soil and silk in which they overwinter.  Later instars of the larva are typically dark brown to black and covered with slime.  Larval damage to horticulture stock may reduce fruit yield and possibly kill young trees, while it is considered aesthetically displeasing in ornamental trees and shrubs. (Ives et al, 1988 and Eaton et al,2006)


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