1. Insect
  2. Small Fruit Crops
  3. Blueberry Pests

Blueberry-Cherry fruitworm

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Grapholita packardi

Pest description and crop damage In the PNW, cherry fruitworm has been found infesting blueberries only in parts of western Washington. Adults are small, dark gray/brownish moths with a wingspan of about 9 to 10 mm. They are active mostly at night and so are rarely seen. Larvae have pink-red bodies with brown or black heads. Newly hatched larvae tunnel into fruit. One larva can easily destroy an entire cluster of berries.

Biology and life history The fruitworm overwinters as a mature larva, hibernating in cavities in dead wood on the bush, or in pruning stubs. As temperatures warm, the larva changes into a pupa, and, about 2 weeks later, the adult emerges in late spring. A few days after emergence, mating and egg deposition occur. Females lay opaque, green-white flattened eggs on the underside of leaves at the time of blossom drop, as well as on developing small green fruit. After eggs hatch, larvae penetrate the berry and begin feeding on the fruit pulp. There is only one generation per year.

Scouting Visual inspection for eggs should begin at petal fall/early fruit set and when adult flight has started. Eggs are opaque and difficult to see; look carefully on the underside of leaves and on small green berries. Larval infestations may be difficult to detect early in the season because there is little external evidence of the insect's presence. Look for a pin-sized entry hole near the stem of any small, shrunken berries that have turned prematurely blue, and then open adjacent berries to find the larvae.

Management-cultural control

Remove overwintering environments for larvae, such as weeds, prunings, and trash around the plants. Also, if possible, manage alternate hosts (e.g. cherry, apple, rose) on field borders.

Home gardeners: Larvae and eggs can be hand-picked if found.

Management-chemical control: HOME USE

Because this is a fruit pest, and because egg laying and hatch occur at bloom and petal fall, great care must be taken if applying pesticides to avoid bee injury with any of the following products. Apply after petal fall, or at night.

  • carbaryl
  • esfenvalerate

Management-chemical control: COMMERCIAL USE

Apply insecticides when larvae are small, usually at petal fall.

  • acetamiprid (Assail and others) at 0.085 to 0.1 lb ai/A. PHI 1 day. Toxic to bees. (Group 4)
  • azadirachtin (Ecozin Plus)-Consult label for rates. PHI 0 days.
  • Bacillus thuringiensis (Bt) (several brands)-Consult label for rate. PHI 0 days. A spreader-sticker increases efficacy. OMRI-listed for organic use.
  • Burkholderia spp. (Venerate)-Consult label for rate. PHI 0 days. OMRI-listed for organic use. Can be hazardous to bees.
  • carbaryl (Sevin and other brands) at 1.5 to 2 lb ai/A. PHI 7 days. Latex-based formulations such as Sevin XLR Plus are less hazardous to bees. Do not apply during bloom. (Group 1)
  • chlorantraniliprole (Altacor) at 0.066 to 0.099 lb ai/A. PHI 1 day. (Group 28)
  • Chromobacterium substsugae (Grandevo)-Consult label for rate. PHI 0 days.
  • cyantraniliprole (Exirel) at 0.065 to 0.088 lb ai/A. PHI 3 days. Do not apply when bees are foraging. Note "Bee Advisory Box" and restrictions on the label. (Group 28)
  • cyclaniliprole (Verdepryn 100SL) at 0.054 to 0.072 lb ai/A. PHI 1 day. Application limited from onset of flowering until flower is complete. Highly toxic to bees. (Group 28)
  • diazinon (several brands) at 0.5 lb ai/A. PHI 7 days. Do not apply to bloom. One application per season allowed; as such, consider other pests that may need to be managed with diazinon. Restricted use pesticide. (Group 1)
  • esfanvalerate (Asana and others) at 0.025 to 0.05 lb ai/A. Aids in control. PHI 14 days. Highly toxic to bees. Restricted use pesticide. (Group 3)
  • fenpropathrin (Danitol) at 0.2 to 0.3 lb ai/A. PHI 3 days. Do not exceed two applications per season. Highly toxic to bees; do not apply during bloom. Restricted use pesticide. (Group 3)
  • indoxacarb (Avaunt) at 0.065 to 0.11 lb ai/A. PHI 7 days. Toxic to bees. Do not apply during bloom. (Group 4)
  • malathion (several brands) at 1.25 lb ai/A. PHI 1 day. Do not apply when bees are actively foraging. (Group 1)
  • methomyl (Lannate) at 0.45 ai/A. PHI 3 days. Do not apply during bloom. Restricted use pesticide. (Group 1)
  • methoxyfenozide (Intrepid 2F) at 0.16 to 0.25 lb ai/A. PHI 7 days. Apply when egg laying begins and again at 100% petal fall (usually 7 to 14 days after first application). Additional applications at 10- to 14-day intervals may be required under high population pressure or sustained moth flights. (Group 18)
  • phosmet (Imidan) at 1.0 lb ai/A. PHI 3 days. Highly toxic to bees. Do not apply during bloom. (Group 1)
  • pyriproxyfen (Esteem 0.86 EC and others) at 0.11 lb ai/A. PHI 7 days. (Group 7)
  • spinetoram (Delegate WG) at 0.05 to 0.09 lb ai/A. PHI 3 days. Read label carefully for restrictions on number of applications allowed. Toxic to bees for three hr following treatment. Do not apply when bees are foraging. (Group 5)
  • spinosad (Entrust) at 0.062 to 0.9 lb ai/A. PHI 3 days. Target eggs at hatch or small larvae. Toxic to bees for three hr following treatment. Do not apply when bees are foraging. Entrust is OMRI-listed for organic use. (Group 5)
  • tebufenozide (Confirm 2F) at 0.25 lb ai/A. PHI 14 days. Apply when egg laying begins and again at 100% petal fall (usually 7 to 14 days after first application). Additional applications at 10- to 14-day intervals may be required under high population pressure or sustained moth flights. Do not exceed 1 lb ai/A product per crop season. (Group 18)
  • tolfenpyrad (Bexar) at 0.28 lb ai/A. PHI 3 days. Highly toxic to bees. Applications must be made at least 8 hr prior to bees foraging. (Group 21)