Insect of the Month - Apple Curculio

 
  Hort Snacks - June 2017
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 Anthonomus quadrigibbus

Crops Affected: Saskatoon berry, chokecherry, apple, crabapple, hawthorn, and pear

Life Cycle:

  • Adults emerge around the time of flowering of Saskatoon berries in the spring
    • Found during flowering and petal drop
    • Adults feed on immature fruit and shoot tips, resulting in puncture marks
  • Eggs laid in punctures at base of young fruit, near the stem, roughly 1 month after peak flowering
    • 1 egg per fruit
  • Larvae feed on developing seeds within fruit, feeding on one seed after another
    • Fruit do not drop off
    • Larvae remain in the fruit until pupation is complete
  • New adults emerge in mid-July; overwinter in leaf litter near host plants
  • 1 generation per year
Symptoms / Damage:
  • Adult = a type of weevil; 5mm long; reddish-brown; long, curved snout
  • Larvae are small and whitish, with brown heads; found in centre of ripe fruit
  • Green fruit and shoot tips with distinctive dark punctures (near base of the fruit)
  • Infested fruit do not drop off
  • Infested fruit may be misshapen and of poor quality
Apple curculio oviposition hole in base of fruit
Apple curculio larva (early stages)
Apple curculio larvae outside of destroyed fruit
Photos by Robert Spencer

Monitoring:
  • Inspect plants shortly before and during fruit set for the presence of adults
  • Inspect fruit for the presence of egg laying punctures
Management:
  • Decis application (3rd) just after petal drop (observe 21 day PHI)
  • Removal of affected green fruit can reduce populations (very time consuming)
  • Effective weed management can help keep populations down
 
 
 
 
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For more information about the content of this document, contact Robert Spencer.
This information published to the web on May 29, 2017.