Cherry fruit fly management strategies

Now is the time for growers to protect fruit from cherry fruit flies.

Much of the Michigan fruit growing region has had above normal precipitation and moderate temperatures over the growing season. Cherry fruit fly emergence, although delayed, is well underway now. Solid catches of cherry fruit fly adults on sticky traps have been detected at the Trevor Nichols Research Center in Fennville, Mich., over the last two weeks, thus female flies are beginning to deposit eggs in fruit.

Control of cherry fruit flies has been traditionally achieved with organophosphate (OP) insecticides, like Guthion and Imidan (phytotoxic on sweet cherries), but some label or processor restrictions may limit their use near harvest. Carbamate and synthetic pyrethroid compounds like Sevin and Asana are also toxic to adult fruit flies, but are generally viewed to be moderately effective because they have a shorter field residual.

There are several new reduced-risk and OP-replacement insecticide products that include cherry fruit flies on their labels. The neonicotinoids Actara, Provado/Admire, Calypso and Assail are labeled for cherry fruit fly control. All three have performed well against cherry fruit flies in small plot field-performance trials. The Spinosyn compounds Delegate and Delegate are active on cherry fruit flies, but their need for ingestion by adult flies requires excellent spray coverage. Rimon has shown good sub-lethal activity on cherry fruit flies, such that when adult flies contact foliar residues, subsequent eggs that are laid in fruit are non-viable.

GF120 NF Fruit Fly Bait (spinosad) is registered on pome fruits for control of cherry fruit flies and is listed by the Organic Materials Review Institute (OMRI) for use in organic production. Because the primary route of entry is through ingestion, applying this product during the fruit fly pre-oviposition period is important for optimal performance. GF120 must be applied with specialized equipment, and is designed for low-volume application. The bait is not rainfast and should be re-applied after rain or heavy dew.

The pre-mix insecticides Voliam flexi and Leverage are also labeled for cherry fruit fly control. Voliam flexi combines the two active ingredients, thiamethoxam and chlorantraniliprole, as a pre-mix formulated compound. Leverage combines the two active ingredients, imidacloprid and cyfluthrin as a pre-mix formulated compound.

As a final management note from Michigan State University Extension, having fly populations infesting fruit that remain on the tree after harvest may be problematic because resident populations represent a source of infestation the following year. Growers with known high fly captures or fruit infestation post-harvest should consider applying an insecticide at this time to combat the resident populations and maintain them at such a low level that the threat of infestation prior to harvest is negligible. Our initial work on post-harvest cherry fruit fly treatments has indicated that the critical time to apply an insecticide is within the first week after harvest.

Summary of insecticides for cherry fruit fly control

Compound trade name

Chemical class

Residual activity

Effectiveness rating**

Effectiveness on SWD***

PHI (days)

Imidan

Organophosphate

14+ days

E

E

7

Sevin

Carbamate

4-5 days

F-G

-

3

Asana, Warrior, Danitol, Baythroid Mustang Max

Pyrethroid

7-10 days

F-G

G-E

3-14

Delegate

Spinosyn

7-10 days

G

E

7

Entrust*

 F

E

Assail, Actara, Provado, Admire Calypso

Neonicotinoid

10-14 days

G

G (curative activity)

7-14

Altacor

Diamide

10-14 days

G

-

10

Rimon

Insect Growth Regulator

10-14 days

G

G (sub-lethal activity)

8

Voliam flexi

Neonicotinoid and Diamides

10-14 days

E

G

14

Leverage

Neonicotinoid and Pyrethroid

10-14 days

G

-

7

*OMRI-approved for organic production
**Effectiveness rating of insecticides (2013 Fruit Management Guide E154); E – excellent, G – good, F – fair
***SWD – spotted wing Drosophila

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