Virus and Virus-Like Diseases of Tree Fruit

Virus and Virus-Like Diseases of Tree Fruit

Viruses cause diseases of most stone and pome fruits. They can affect size, shape and quality of fruit, and can induce colour patterns and distortions on leaves. Viruses can also cause dieback, bark symptoms, gumming, stock-scion incompatibilities and tree death. When viruses infect fruit trees they may produce visible symptoms in some varieties, but remain latent in others.

cherry mottle leaf virus Cherry mottle leaf virus

How Viruses are Spread

Tree fruit viruses are spread primarily by infected propagative material, including rootstocks, budwood or scionwood and finished plants. Most viruses also have other methods of short-distance spread, although not all are known. Insects or other organisms that spread viruses are known as “vectors”. Examples of virus vectors include aphids, leafhoppers, psyllids, mealybugs, mites, and some species of nematodes. Many tree fruit viruses can spread through natural root grafting to neighbouring trees. Some tree fruit viruses can be spread in pollen.

Cultural Control

Plant only nursery stock certified as virus-free from a reliable source
When propagating their own trees, growers should be sure that both rootstock and scion are free from damaging viruses.
Remove trees showing virus symptoms to protect other trees in the planting from becoming infected.
Contact your crop management advisor for further information.

pear stony pit virus Pear stony pit virus

apple mosaic virus Apple mosaic virus

Cherry rasp leaf virus - Typical leaf symptoms including distortion and enations.

Apple russet ring - a virus-like disease, causal agent unknown. Shown on immature 'Gala' apple.

Cherry short stem - a virus-like disease, causal agent unknown. Shown on 'Lambert' cherry.

apricot ring pox Apricot ring pox virus

Unidentified virus in plum, causing severe shot hole and defoliation.

June 2006

Also see Little Cherry Virus
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