Ministry of Agriculture

Cherry Fruit Flies (Western and Black cherry)

Hosts

Sweet and sour cherry, bittercherry (Prunus emarginata), Mahaleb cherry (P. mahaleb)

Damage

Larvae (maggots) feed in the flesh near the pit of cherries rendering them unmarketable.


Western cherry fruit fly larvae in cherry Photo courtesy Agriculture & Agri-Food Canada	Western cherry fruit fly adult on cherry with larval exit holes

Identification

Adult - Slightly smaller than house fly, black body with yellow markings near base of wings and white stripes across abdomen. Wings have black markings, which are used to identify this pest from related fruit flies (see wing pattern pictures below).
Larva - White, legless maggot-like with no distinct head; about 5-6 mm long when mature.
Pupa - About 4-5 mm long, gold to brown colour, elongate-oval shape.


Western cherry fruit fly, common wing pattern (Rhagoletis indifferens)	Western cherry fruit fly, rare wing pattern (Rhagoletis cingulata)

Black cherry fruit fly (Rhagoletis fausta)	Walnut husk fly (Rhagoletis completa)

Apple maggot/snowberry fruit fly (Rhagoletis pomonella/Rhagoletis zephyria)	Currant fruit fly (Rhagoletis ribicola)
	Photo Credits for wing pattern images: Naomi DeLury, Howard Thistlewood , Michael Weis and Jacqueline Sztepanacz, Agriculture & Agri-Food Canada, Pacific Agri-Food Research Centre, Summerland.
Rhagoletis berberis

Life History

Cherry fruit flies overwinter as pupae in the top 2-5 cm of soil under cherry trees. Adults are present from late May into August, generally peaking from early to mid-July, depending upon location. Black cherry fruit fly adults begin emerging 1-2 weeks before western cherry fruit flies. Five to 9 days after emerging, female flies lay eggs singly in cherries and larvae feed for 1-2 weeks around the pit before cutting exit holes and dropping to the ground to pupate. There is only one generation each year; 3-4% can have a second generation in August and a similar proportion can overwinter for 2 or more years.

Monitoring

Monitor for presence of cherry fruit flies using commercially available sticky yellow traps (bait with ammonium carbonate to increase attractiveness). Rebell™ traps are more attractive than other types of yellow sticky traps. Hang the traps by mid-May at eye-level in exposed sunny parts of the trees; clear all the leaves and twigs for a distance of 40 cm from each trap. Use a minimum of four traps with an average of two traps per hectare in large solid blocks. Mixed plantings require more traps. Inspect traps daily until the first fly is caught, then at weekly intervals. Yellow sticky traps are not very efficient for detecting fruit flies, especially when numbers are low, such as in well-managed commercial blocks. Because outside unmanaged sources are a common threat to most growers, it is important to monitor borders nearest these sources. This will ensure early detection of flies entering the block and timely application of protective sprays to prevent establishment and spread. In the presence of cherries, 90% of adults will not travel beyond a short distance, but some can fly up to 500 m or more.

Control

Cultural - Destroy infested cherries before the larvae emerge. Removal of all cherries before they all turn red will greatly reduce fruit fly numbers for next season. At the time of cherry bloom, search out and destroy any unmanaged hosts within a distance of at least 250 m.

Chemical - The low efficiency of yellow sticky traps and zero tolerance for fruit flies in fruit requires protection of the fruit throughout the summer when fruit flies are active, regardless of trapping results. If using traps, apply a control product within 5 days of first fly capture and maintain control until harvest. In the absence of traps, begin protecting fruit about the time Lambert cherries begin to colour. Research shows female fruit flies will lay eggs in green fruit. This means application of sprays to the new later maturing varieties when the fruit may still be green.

The following table presents information on recommended control products. NOTE: If your cherries are destined for foreign markets, check with your packinghouse, crop certifier or broker to confirm which spray products can be applied to cherries entering the country (MRL present) or allowed by the buyers. Do not risk fruit infestations by exceeding the spray intervals. Re-apply the products after any measurable rain event to ensure fruit flies are exposed to lethal residues.

Products Recommended for Cherry Fruit Fly Control

Trade Name	Active Ingredient	Target Stages	Number of Applications	Spray Interval¹ (days)	Pre-harvest Interval (days)
Admire 240F² or Alias 240 SC²	imidacloprid	Larvae, adults	2	10	10
Sevin XLR²	carbaryl	Adults	No limit	5 - 7	2
Cygon 480 or Lagon 480 EC	dimethoate	Larvae, adults	1	21	21
Diazinon 50W	diazinon	Adults	3	7	10
Guthion 50WP/ Sniper 50 WP	azinphos-methyl	Adults	2	14	15
Zolone Flo	phosalone	Adults	3	12 - 14	14
Entrust 80W	spinosad	Adults	4	7 - 10	7
GF-120	spinosad	Adults	10	7	0
¹ Minimum days between sprays when applied at recommended rates in absence of rainfall/overhead irrigation ² Minimize use to avoid mite problems

Do not risk fruit infestations by exceeding the spray intervals. Re-apply the products if measurable rain occurs within 24-48 hours of application.

Sevin XLR, Guthion 50WP, Sniper 50WP, Diazinon, Zolone Flo, Entrust 80 W and GF-120 sprays will only control adult fruit flies. Apply the first spray not later than 5 days after capture of the first fly followed by sprays at recommended intervals to maintain protection of fruit to harvest.

Entrust 80W and GF-120 NF are approved for use in organic cherry blocks. Both products contain spinosad. Entrust will also control leafroller and bud moth larvae present at the time of application. GF-120 requires a special sprayer which can be purchased or fabricated - do not use an air-blast sprayer. Carefully read the label instructions before mixing and applying GF-120. Because GF-120 does not control other insect pests (such as cherry fruitworm, leafrollers, aphids), growers should monitor for the presence of other pests to determine need for control. To prevent damage by other insect pests, consider applying fruit fly control products that also provide protection against other major pests present (for example, Admire, Alias, Cygon or Zolone for aphids; Sevin, Diazinon or Guthion/Sniper for cherry fruitworm, leafrollers).

Admire and Alias have some residual contact activity against adult flies (2-3 days) but will kill young larvae hatching in the egg for 10 to12 days post treatment because it is absorbed into the fruit. These products will also move into the branches and out to the growing tips where it will control any black cherry aphids present. Some research shows mite populations increase after neoticotinoid products such as Admire and Alias are applied. Therefore do not use Admire or Alias more than twice per season. Avoid use of any chemicals harmful to predatory mites in blocks treated with Admire and Alias to avoid possible mite flare-up. Monitor mites the following spring to assess the risk of mite problems.

Because Cygon and Lagon may not protect the fruit up to harvest, an additional application of another product may be required. Be aware of the preharvest intervals. For sour cherries, do not apply Cygon or Lagon more than twice per season. Apply the second spray 14-21 days after the first.

A very important application is a post harvest spray of Admire, Alias (if either only used once before), Cygon or Lagon to prevent late-emerging fruit flies breeding in unharvested whole or split cherries. One estimate suggests that 10,000 cherries per acre remain on trees post-harvest.

Field reports indicate control products formulated as emulsifiable concentrates (EC) can cause severe leaf burn and possible drop in Lapin, Sam, Stella, and Sweetheart cherry varieties. Also, some leaf burn and drop may occur if GF-120 is applied to undersides of leaves.

Updated February 2010

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