Green Fruitworms

Green Fruitworms

Hosts

Fruit trees (mainly apple and pear), many native trees including willow, birch, poplar and maple.

Damage

Buds - Small entry holes in buds, chewed petals and flower parts.
Leaves - Chewed young terminal leaves.
Fruit - Wide irregular holes in small fruit resulting in large russeted scars and deep pits in mature fruit; feeding often distorts pears.

green fruitworm damage on apple Deep wounds in fruitlets from larvae feeding; later deep russeted wounds or holes in mature fruit
Photo courtesy Agriculture & Agri-Food Canada

green fruitworm damage on apple Green fruitworm feeding damage on apple

Identification

Larva - Yellowish-green to blue-green body with white to yellow longitudinal stripes and green to tan head; young larvae may have dark spots; mature larvae up to 35 mm long. Very young larvae will hang from a silk thread when disturbed; older larvae curl up when disturbed and walk without looping.

fruitworm on pear Fruitworm on pear
Photo courtesy Agriculture & Agri-Food Canada

brown fruitworm Brown fruitworm

Life History

Green fruitworms overwinter as adults, pupae or eggs, depending on the species. Eggs hatch from before bloom to after petal-fall, and larvae may be present from pink to 3-4 weeks after petal- fall. Young larvae feed on flower parts and new leaves while older larvae feed mainly on young fruit. Mature larvae drop to the ground and enter the soil where they remain during pupation. Moths emerge in fall or spring, depending on the species. There is one generation per year.

Monitoring

Examine fruit bud and blossom clusters and terminal leaves for larvae in spring. After blossoms open, use limb tap samples to determine the need for control action.

Control

Chemical - Recommended products and timing for green fruitworm control in apple are:

Timing Product

tight cluster Diazinon + oil, Guthion or Sniper

pink Diazinon

blossom Dipel, Foray, or Bioprotec (Bacillus thuringiensis)

petal-fall Endosulfan, Thiodan, Dipel, Foray or Bioprotec

Recommended products and timing for green fruitworm control in pear are:

Timing Product

pink Diazinon, Guthion or Sniper

blossom Dipel, Foray, or Bioprotec (Bacillus thuringiensis)

petal-fall Diazinon, Guthion, Sniper, Dipel, Foray or Bioprotec

Note: Avoid using Diazinon, Guthion and Sniper as they are disruptive to pear psylla predators. These products applied at pink or petal-fall will also control other leafrollers (except resistant fruittree and obliquebanded leafrollers) and bud moth. The pink spray will also control Bruce spanworm. These materials are toxic to bees. An application of a biological insecticide containing Bacillus thuringiensis (Dipel, Foray, or Bioprotec) during bloom or at petal-fall will control green fruitworms and leafrollers and is not toxic to bees or predatory insects and mites. Best spray timing varies with species present and weather conditions. See discussion of Bacillus thuringiensis under Fruittree and European Leafrollers.

March 2006

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