Grape-Spotted wing drosophila

Drosophila suzukii

For pest description, crop damage, biology, life history, sampling and cultural management

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This insect has limited known commercial impact on wine grapes in Oregon and Washington to date. Adult SWD can be found feeding on grapes directly before harvest. Wine grapes in Western production regions are more susceptible to SWD impact, especially when the berry surface area is cracked due to insect damage, bird damage or Botrytis. Research has shown that drosophilid flies may vector spoilage bacteria under these conditions, thereby influencing fruit quality. Growers should take necessary steps to ensure minimal berry damage. Virtually no fully intact berries collected in vineyard studies have SWD eggs or larvae developing in them. A very small portion of damaged berries may contain eggs and an even smaller portion of eggs manages to develop to adulthood. However, research continues to determine seasonal differences.

Management-chemical control: HOME USE

  • acetamiprid-In field tests, this product has provided inconsistent control of SWD. Group 4A insecticide.
  • azadirachtin (neem oil)-This product has been shown to provide about 25% control of SWD. Some formulations are OMRI-listed for organic use.
  • pyrethrins (often use in a mix with other ingredients)-These products provide about 80% control of SWD but have no residual activity. Group 3A insecticide. Some formulations are OMRI-listed for organic use.
  • spinosad-This product generally provides a relatively high level of adult control, and 5-7 days residual activity, depending on conditions. Under rainy conditions, this residual period may be shorter. Some formulations are OMRI-listed for organic use. Group 5 insecticide.

Management-chemical control: COMMERCIAL USE

Note: Treatment with pesticides is generally not necessary for this pest. However, if infestations and damage are noticed, the following insecticides can be used to manage this pest.

Laboratory tests and field experiments indicate that many of the pesticides registered for use in grapes are effective in controlling the adult SWD. Although SWD may not be listed on a label, it is legal to use for SWD management. The products listed below target the adult stage of SWD. The relative level of control indicated for each pesticide was determined under both laboratory and field conditions.

  • azadirachtin (Aza-Direct, Neemix and other brands)-Consult label for rate. PHI 0 days. Achieves approximately 25% control of SWD. Some formulations are OMRI-listed for organic use.
  • bifenthrin (Brigade and other brands) at 0.1 lb ai/a. PHI 30 day. Toxic to bees and should not be used when bees are foraging. Toxic to fish and other aquatic invertebrates. Synthetic pyrethroids, such as bifenthrin, provide 100% mortality of SWD, and 10 to 14 days residual control in the field. Under rainy conditions this residual period may be shorter. Although SWD is not listed on the label, it is an effective and legal use.
  • Group 3A insecticide. Restricted use pesticide.
  • carbaryl (Sevin and other brands) at 1.5 lb ai/a. PHI 7 days. Use postbloom only. Carbaryl is a carbamate chemistry that is broad-spectrum and provides 100% control of SWD. Toxic to bees; do not apply when bees are foraging. Toxic to aquatic invertebrates. Group 1A insecticide.
  • fenpropathrin (Danitol) at 0.2 to 0.4 lb ai/a. PHI 21 days. Do not exceed two applications per season (0.8 lb ai/a/year). Toxic to bees and should not be used when bees are foraging. Toxic to fish and other aquatic invertebrates. Synthetic pyrethroids, such as fenpropathrin, provide 100% mortality of SWD, and 10 to 14 days residual control in the field. Under rainy conditions this residual period may be shorter. Group 3A insecticide. Restricted use pesticide.
  • horticultural oil (several brands)-Consult label for rate. Provides some control of SWD but has no residual activity. May cause spotting on fruit. Some formulations are OMRI-listed for organic use.
  • malathion (several brands) at 2.0 lb ai/a. PHI 3 day. Toxic to bees and most aquatic invertebrates, and carry the risk of mammalian toxicity. Do not apply when bees are foraging. They provide 100% mortality of SWD, and 7 to 10 days residual control in the field. Under rainy conditions this residual period may be shorter. Group 1B insecticide. This is an organophosphate insecticide.
  • pyrethrin (Pyganic and other brands)-Consult label for rate and use directions. Toxic to bees; do not apply when bees are foraging. Highly toxic to fish. Provides 80% control of SWD but has no residual activity. Some formulations are OMRI-listed for organic use. Group 3A insecticide.
  • spinetoram (Delegate WG) at 0.047 to 0.078 lb ai/a. PHI 7 days. Retreatment interval 4 days. Do make more than 5 applications per season (not to exceed 0.305 lb ai/a per year). Toxic to bees for three hours following treatment. Do not apply when bees are foraging. May provide 100% mortality of SWD, and 5 to 7 days residual control in the field. Under rainy conditions this residual period may be shorter. Group 5 insecticide.
  • spinosad (Success or Entrust) at 0.062 to 0.124 lb ai/a. PHI 7 days. See label for use in grape for OR, WA and ID. Entrust is OMRI-listed for organic use. Toxic to bees for three hours following treatment. Do not apply when bees are foraging. May achieve 100% mortality of SWD, and provide 5 to 7 days residual control in the field. Under rainy conditions this residual period may be shorter. The bait formulation of spinosad (GF-120) is not effective against SWD. Group 5 insecticide. Do not make more than 2 consecutive applications of Group 5 insecticides. Do not apply more than 0.45 lb ai/a per season.