cherry maggots

Asked July 8, 2013, 9:49 PM EDT

For the first time in 20 years I have found maggots in both the Stella and sour backyard cherry trees. I live in a marine town, Port Townsend, on the Olympic peninsula in WA State. Should I destroy all the remaining fruit on the trees and do I have to be careful with the fallen cherries. Thanks Richard Thomas

Jefferson County Washington trees and shrubs insect issues fruit trees horticulture

1 Response

I like Port Townsend and have been there many times. I would destroy all the fruit my self. here is more information

PNW Insect Management Handbook
Printed page URL: pnwhandbooks.org/insect/node/1655
Cherry-Western cherry fruit fly
Photo of Western cherry fruit fly
Western cherry fruit fly
Rhagoletis indifferens Curran
Immature showing damage
Photo of Western cherry fruit fly
Western cherry fruit fly
Rhagoletis indifferens Curran
Female adult
Photo of Western cherry fruit fly
Western cherry fruit fly
Rhagoletis indifferens Curran
Egg(s) on host
Photo of Western cherry fruit fly
Western cherry fruit fly
Rhagoletis indifferens Curran
Immature on host
Rhagoletis indifferens Pest description and crop damage Adults are somewhat smaller than a housefly. They have brownish to black wings with dark bands. White maggots infest cherries. The mature maggot makes a hole in the cherry as it exits. In the Northwest, the western cherry fruit fly is known to infest both home grown and commercial cherries. Western cherry fruit fly is also found in wild bitter cherry, Prunus emarginata. Biology and life history The flies overwinter as pupae in the soil. The adult flies emerge from the soil from mid-May, about 5 weeks before harvest, until the end of July. Peak emergence often coincides with harvest. Adults feed on honeydew on leaves and pollen. After 7 to 10 days, females lay eggs under the skin of the fruit. The eggs hatch, and the larvae burrow toward the pit of the fruit. There they feed for 10 to 21 days before boring out and dropping to the ground to pupate. There is one generation per year. Adults emerge early the following season. A few pupae of western cherry fruit fly may remain in soil as long as 3 years. Scouting and thresholds There is no tolerance for cherry fruit fly: the threshold is zero. Degree day models are used to determine first emergence in the major cherry production regions of the Pacific Northwest. Consult with your county Extension agent to determine the development of cherry fruit fly populations in your area. Yellow sticky traps hung in sunny parts of the tree will attract adults. Monitor daily. Management-cultural control Home orchardists: Grow early-maturing varieties such as 'Chelan'. Pick fruit within 8 to 9 days of catching the first flies, which will happen before egg hatch. Remove all fruit from the trees to eliminate sites for the fly to reproduce. Cultivation of the soil has not been effective, as the pupae are very hard-shelled. Management-chemical control: HOME USE Begin spraying about May 20 to 25 and continue through harvest. Spray at 7 to 10-day intervals.
  • acetamiprid
  • carbaryl
  • esfenvalerate
  • gamma-cyhalothrin
  • imidacloprid
  • kaolin clay (Surround at Home™)-Applied as a spray to leaves, stems, and fruit, it acts as a repellant to some insect pests..
  • malathion
  • pyrethrins
Management-chemical control: COMMERCIAL USE Warning These materials are hazardous to bees. Do not use during bloom or if bees are foraging in the orchard. Malathion sprays may be less hazardous to bees.
  • acetamiprid (Assail 70WP) at 0.57 to 0.85 oz/100 gal water (2.3 to 3.4 oz/a). PHI 7 days. REI 12 hours. No more than 4 applications per season.
  • azinphos-methyl (Guthion Solupak) at 1.5 lb/a. PHI 15 days. REI 15 days. Do not exceed two applications or 3 lb/a per season. Extremely toxic to fish and wildlife; avoid spray drift and runoff to surface waters. Guthion sales are cancelled as of September 30, 201: existing grower stocks can be used up.
  • carbaryl (Sevin 4F of Carbaryl 4L) at 0.75 to 1 pt/100 gal water (1.5 to 2 quarts/a). REI 12 hr. Extremely toxic to aquatic invertebrates; avoid spray drift and runoff to surface waters.
  • carbaryl (Sevin XLR Plus) at 0.5 to 1 quart/100 gal water (2 to 3 quarts/a). PHI 3 days. REI 12 hr. Extremely toxic to aquatic invertebrates; avoid spray drift and runoff to surface waters.
  • chlorpyrifos (Lorsban 75WG) at 0.5 lb/100 gal water (2 lb/a). PHI 21 days. REI 4 days. Sour cherries only. Defoliates sweet cherries. Generic labels for chlorpyrifos are also available. Extremely toxic to fish and aquatic invertebrates; avoid spray drift and runoff to surface waters.
  • diazinon (Diazinon 50W) 1 lb/100 gal water (4 lb/a). Do not exceed one in- season application per year. PHI 21 days. REI 4 days.
  • dimethoate (Dimethoate 267) at 0.75 to 1.5 pints/100 gal water (3 to 4 pints/a). PHI 21 days. REI 2 days. Do not exceed one preharvest application per season, within 7 days of cherry fruit fly emergence or at least 21 days before harvest if there is no adult cherry fruit fly activity. Can cause leaf burning. One post-harvest application permitted in Oregon, Idaho, and Washington at 1.5 pint/100 gal water. Do not feed or graze livestock on cover crops in treated orchards. Do not mix with Syllit. Do not use on cherries to be exported to Japan.
  • dimethoate (Dimethoate 400) at 0.5 pint/100 gal water (2 pints/a). PHI 21 days. REI 2 days. Do not exceed one preharvest application per season, within 7 days of cherry fruit fly emergence or at least 21 days before harvest if there is no adult cherry fruit fly activity. Can cause leaf burning. One post-harvest application permitted in Oregon, Idaho, and Washington at 1 pint/100 gal water. Do not feed or graze livestock on cover crops in treated orchards. Do not use on cherries to be exported to Japan.
  • dimethoate (Dimethoate 4E) at 2 pints/a. PHI 21 days. REI 2 days. Do not exceed one pre-harvest application per season, within 7 days of cherry fruit fly emergence or at least 21 days before harvest if there is no adult cherry fruit fly activity. Can cause leaf burning. One post-harvest application permitted in Oregon, Idaho, and Washington at 1 pint/100 gal water. Do not feed or graze livestock on cover crops in treated orchards. Do not mix with Syllit. Do not use on cherries to be exported to Japan.
  • esfenvalerate (Asana XL) at 2 to 5.8 fl oz/100 gal water (4.8 to 14.5 fl oz/a). PHI 14 days. REI 12 hr. May aggravate spider mite problems. Extremely toxic to fish and aquatic invertebrates; avoid spray drift and runoff to surface waters.
  • imidacloprid (Provado 1.6F) at 2 fl oz/100 gal water (4 to 8 fl oz/a). PHI 7 days. REI 12 hr. Do not use until pollination is complete and bees are no longer present. Generic formulations of imidacloprid are available.
  • malathion (Malathion 5) at 6pint/a. PHI 3 days. REI 12 hr. May injure certain varieties of sweet cherries.
  • malathion (Malathion ULV) at 12 to 16 oz/a. PHI 1 day. REI 12 hr. Apply ultra low volume (ULV) by air only with equipment adapted for ULV. Treatments must be timely and thorough: treat all interplanted foliage. Repeat treatments after heavy rain if label allows.
  • phosmet (Imidan 70W) at 2.125 to 2.5 lb product/a. PHI 7 days. REI 3 days. For sour cherries only. Do not exceed three applications per season. May be phytotoxic. Highly toxic to bees and fish. Avoid spray drift and runoff to surface waters.
  • spinetoram (Delegate* 25WG) at 1.1 to 1.75 oz/100 gal water (4.5 oz/a). PHI 7 days. Apply no less than one week apart, with a maximum 4 applications per season.
  • spinosad (Success 2L) at 1 to 2 fl oz/100 gal water (4 to 8 fl oz/a). PHI 7 days. Do not exceed 29 fl oz/a/season.
  • spinosad (Entrust 80WP or 2SC) at 0.4 to 0.8 oz or 1.3 to 2.7 fl oz/100 gal water (1.25 to 2.5 oz or 4 to 8 fl oz/a). ). PHI 7 days. REI 4 hr..
  • spinosad bait (GF-120 NF) at 20 fl oz/a. No PHI listed. REI 4 hr. Apply every 7 days. Apply immediately upon first emergence. Can be applied by air or with an all-terrain vehicle. Apply 0.8 to 1 gal/a with a D2 nozzle (without a core) attached to an ATV traveling at 6 to 7 mph.

Related Links

Hollingsworth, C.S. (Ed.). 2013. Pacific Northwest Insect Management Handbook.
© Oregon State University.

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