ORIENTAL FRUIT MOTH (OFM) Grapholita molesta

Description:

Adult:
Gray mottled moths with a coppery band at the tips of the wings.

Eggs:
Laid singularly, not in clusters. Pinhead sized, disc-shaped and transparent white when first laid. As they mature they become opaque white and develop a red ring. Just before hatching the black head of the larva becomes visible.

Larvae:
Newly hatched larvae are pinkish white with a black head. Mature larvae are about 0 .75 in or 19 mm long and pinkish white with a mottled brown head. In walnuts, codling moth larvae look similar to those of the navel orangeworm. However, they do not have the crescent-shaped marks on the second segment that distinguish navel orangeworm larvae.

Hosts:
Apples, pears, quince, walnuts, plums, and infrequently other stone fruits.

Damage:
Pome and Stone Fruits

  • Codling moth larvae mainly damage fruit with deep entries and stings.
  • In deep entries, larvae bore to the core and feed in the seed cavity area.
  • Stings occur primarily when a stomach poison is used and larvae enter the fruit a short way before dying or leaving. Affected areas heal leaving a small scar.
  • Larvae may enter through the sides, stem end, or calyx end of the fruit.

Walnuts

  • Damage caused by codling moth is different with each generation.
  • First generation larvae reduce yield directly by causing nutlets to drop from tree.  Damaged nutlets have frass usually at the blossom end.
  • Nuts attacked by second generation remain on trees but are unmarketable because of feeding damage on kernel. Feeding damage can also be detected by looking for frass produced by larvae at the point of entry into the husk. CM damaged nuts also serve as breeding site for navel orangeworm.

Phenology:

  • Two to four generations per year depending on weather and location.
  • Overwinters as full-grown diapausing larva.
  • Emerges March or April in California; emerges in late April or May in Washington.
Oriental Fruit Moth

ORIENTAL FRUIT MOTH (OFM) Grapholita molesta

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