Little cherry virus -2Little cherry virus -2 Facts and controlsFacts and controls

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Symptoms Symptoms

• Small cherriesSmall cherries

• Higher packing house Higher packing house cull percentagecull percentage

• Negative impact on Negative impact on color, shape & tastecolor, shape & taste

10.5 row Lambert & Royal Ann10.5 row Lambert & Royal Ann

Little cherry virus -2 samplesLittle cherry virus -2 samples

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SymptomsSymptoms• Bing & Sweetheart Bing & Sweetheart

relatively tolerantrelatively tolerant

• Severe symptoms first Severe symptoms first year of infectionyear of infection

• Fruit size & color Fruit size & color return to return to NEARNEAR normal, but still normal, but still reducedreduced

• Fruit flavor never Fruit flavor never recoversrecovers

Replace this picture Replace this picture with picture ofwith picture ofBings and/or Bings and/or

Sweethearts with little Sweethearts with little cherry viruscherry virus

Little cherry virus-2 on ‘Sweetheart’

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Pathogen

Little cherry disease can be caused by one Little cherry disease can be caused by one of two agentsof two agents

– Little cherry virus -1Little cherry virus -1• Prevalent in Eurasia, but also with limited distribution in Prevalent in Eurasia, but also with limited distribution in

North AmericaNorth America• Insects that transmit this virus are unknownInsects that transmit this virus are unknown

– Little cherry virus -2Little cherry virus -2• Most common form of the disease found in western Most common form of the disease found in western

North AmericaNorth America• Transmitted by at least one species of mealybugTransmitted by at least one species of mealybug

Western X disease appears similarWestern X disease appears similar– Actually caused by special group of bacteriaActually caused by special group of bacteria

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TransmissionTransmission

• Apple mealybugs Apple mealybugs spread the little cherry spread the little cherry virus-2virus-2– Can be controlled with Can be controlled with

insecticide sprayinsecticide spray

• It is highly likely other It is highly likely other types of mealybugs types of mealybugs transmit the virus, but transmit the virus, but not confirmednot confirmed

Apple mealybugsApple mealybugs

Grape mealybugsGrape mealybugs

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TransmissionTransmission

• Transmitted via grafts of non-certified Transmitted via grafts of non-certified budwood or rootstocks budwood or rootstocks

• Root grafting can pass virus on to healthy Root grafting can pass virus on to healthy treestrees

• Best defense is to plant virus-tested trees Best defense is to plant virus-tested trees from certified nurseries. Click here for a from certified nurseries. Click here for a list of list of certified nurseries certified nurseries

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ControlControl

• Control mealybug vectorsControl mealybug vectors

• Control wild cherries (bitter Control wild cherries (bitter cherry) near orchardcherry) near orchard

• Immediate & proper Immediate & proper removal of infected trees removal of infected trees

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Proper tree removalProper tree removal

• As cut tree limbs start As cut tree limbs start to dry, the insects (and to dry, the insects (and viruses) may move to viruses) may move to nearby trees. nearby trees.

• To prevent vector (and To prevent vector (and virus) movement.virus) movement.– Apply good cover spray Apply good cover spray

of broad spectrum of broad spectrum insecticide/miticide to insecticide/miticide to tree about 7 days before tree about 7 days before cutting.cutting.

Goal: Prevent the spread of virusGoal: Prevent the spread of virus

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Proper Tree RemovalProper Tree Removal

• Or remove trees in Or remove trees in winter while insects are winter while insects are dormant. dormant.

• Remove all of the wood Remove all of the wood from the orchard before from the orchard before mild spring weather.mild spring weather.

Even though Bing and Sweetheart Even though Bing and Sweetheart trees can “bounce back” after virus trees can “bounce back” after virus

infection, but they never return to infection, but they never return to full production.full production.

Healthy cherry tree Healthy cherry tree surrounded by trees infected surrounded by trees infected

by little cherry virus-2.by little cherry virus-2.

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Things to consider

• Even when you remove an infected tree, the virus may still be a threat

• Keep an eye on surrounding trees for the next 2 to 3 years

• If in doubt, have trees tested

Newly infected tree may take 2-3 years to show symptoms

Symptomatic tree to be removed

Root graft

Things to considerThings to consider

• Ignore the disease and Ignore the disease and it wil l continue to spreadit wil l continue to spread

– To nearby treesTo nearby trees– To your neighbors’ To your neighbors’

orchardsorchards• Litt le cherry disease Litt le cherry disease

reduces economic reduces economic viabil i ty of your orchard viabil i ty of your orchard

– Decrease in yieldDecrease in yield– Increase in cullsIncrease in culls– Fruit f lavor never Fruit f lavor never

recoversrecovers

Above: Cherries with l i t t le cherry virusAbove: Cherries with l i t t le cherry virus

Below: Virus-free Bing cherriesBelow: Virus-free Bing cherries

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Questions?Questions?

Tim SmithTim Smith

WSU Extension EducatorWSU Extension Educator

509-667-6540509-667-6540

smithtj@wsu.edusmithtj@wsu.edu

Dr. Ken EastwellDr. Ken EastwellFruit Tree Clean Plant NetworkFruit Tree Clean Plant NetworkWSU-Prosser IARECWSU-Prosser IAREC509-786-9385509-786-9385keastell@wsu.edukeastell@wsu.edu

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