Insect of the Month - Raspberry Sawfly

 
  Hort Snacks - October 2017
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 Monophadnoides geniculatus

Crops Affected: all caneberry crops (raspberry, blackberry, loganberry) and possibly gooseberry

Life Cycle:

  • Adults emerge in spring
  • Lay eggs at flowering in leaf tissues
  • Larvae feed for 2-3 weeks on leaf undersides, flower buds, young fruit, growing shoots and tender bark of new growth
  • Particularly destructive on primocanes due to lush growth later in season
  • Drop to ground and overwinter in a cocoon
  • Pupation occurs in spring
  • 1 generation per year
Symptoms:
  • Adult are small, black insects with a yellow band on their abdomen and clear wings
  • Larvae are light green caterpillars with white bristles, which can reach 10-18 mm in size
  • Typically difficult to see larvae on leaves due to their colouration and feeding location
  • Larval feeding on the leaves produces small, elongated holes between the leaf veins
  • Heavy infestations results in skeletonized leaves (veins intact)
Raspberry sawfly feeding damage - Note elongated holes between veins - light skeletonization
Photo by Robert Spencer
Monitoring:
  • Visually inspect leaves in June
  • Determine the number of larvae present
  • Determine whether skeletonization is occurring and if controls are required
  • Damage by raspberry fruitworm larval early season feeding on fruiting cane laterals can be confused with raspberry sawfly damage, which is mainly on new primocane growth
Management:
  • Vigorous plantings can tolerate a fair amount of feeding and damage before controls are required
  • Chemical controls are available if significant damage is occurring
 
 
 
 
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For more information about the content of this document, contact Robert Spencer.
This information published to the web on September 29, 2017.