13 Results

Virus-tested Stone Fruit

All stone-fruit clones listed in this index were tested at NRSP5 facilities and were found to be free of known viruses and virus-like agents detectable by the following woody indicators:


  • Shirofugen and Kwanzan flowering cherry
  • Prunus tomentosa
  • Shiro plum
  • Elberta or GF305 Peach
  • Tilton apricot
  • Bing, Sam and Canindex cherry
Please note tests with a cRNA probe found many peach and nectarine clones to be infected with peach latent mosaic viroid (PLMVd). This viroid caused no obvious symptoms on any of the indicators listed above or on the infected peach or nectarine clones.  Most varieties in the NRSP5 collection are now free of this viroid, but several are not.  A release must be signed before PLMVd-infected budwood is distributed to anyone.


You may order budwood for propagation here.

Plum Mosaic

Causal agent: unknown

Unlike symptoms caused by this pathogen in peach ( Peach mosaic), symptoms only appear on leaves and delayed foliation or dwarfing rarely occur in plum.

Leaf symptoms develop as small chlorotic flecks, rings, and vein-feathering patterns. Leaves are often deformed and distorted by the uneven development of affected tissues.

Symptoms appear annually and their severity is consistent.

Summary: Nemeth 1986

Peach Yellow Bud Mosaic

Causal agent: Tomato Ringspot Virus

Synonyms: Winters peach mosaic, Winters disease.

Leaf symptoms show as irregular, feather-edged small to large chlorotic spots along main veins; mostly towards the leaf base and predominantly on one side of the midrib. Pinching, cork-screwing, and puckering distortion also occurs. The blades bend laterally toward the chlorotic areas, where the blotches drop out, leaving shot-holes. This ‘mosaic’ phase is followed in the second year of infection by the ‘yellow bud’ phase.

In spring, the growth of leaves from some buds is arrested, producing shortened tufts of small, pale yellow leaves. The tufts often turn brown and die or remain small. Some leaves may expand and form rosettes. As the infection moves slowly upward, fruits are produced only at branch extremities and become small and shrunken.

Summary: Nemeth 1986

Peach Rosette Mosaic

Causal agent: peach rosette mosaic nepovirus

The most characteristic trait of the disease is the rosetting of the leaves, which results from the reduced growth of the internodes with respect to their vertical axis. Initially, leafing is delayed considerably, and on those leaves that develop early, chlorotic spots appear in variable sizes and numbers. These spots are either creamy or yellow in color; in some cases, the spots may even be translucent. Tissue growth in the affected areas tends to be inhibited and results in deformation or wavy margins. Leaves developing later appear normal, although they tend to be somewhat broader.

Fruit distribution, if produced at all, is sparse.

Summary: Nemeth 1986

Peach Mosaic

Causal agent: Peach Mosaic Virus

Leaves develop various chlorotic patterns during spring and early summer. The pale green discoloration varies from tiny flecks to large blotches, streaks, and vein feathering. As these spots become necrotic and fall out “shot-hole” patterns form. Leaves darken in late summer, making the chlorotic patterns less visible. Streaks or spots appear on some flower petals.

Fruits first exhibit symptoms around the time their stones harden and intensify as they mature. Surfaces become rough and bumpy as retarded tissue growth causes depressions; often the ventral suture is deformed. Infected fruits not developing these symptoms usually experience delayed maturity. In both cases, fruits never obtain a normal size.

James 1993 reported monoclonal antibody specific to mottle leaf virus reacted with peach mosaic virus in ELISA assay and Western blot analysis.

Key Reference: James 1993
Summary: Nemeth 1986


Arabis Mosaic

Causal agent: Arabis mosaic nepovirus

As this nepovirus was detected during the course of glasshouse testing of seed source trees by herbaceous indicator plants, there are no data yet on the symptoms and damage caused on peach. However, it has been attributed to induce Cherry rasp leaf (European).

Enations on the lower leaf surface present moderate symptoms of leaf deformation and rosette formation.

Summary: Nemeth 1986

Apricot Mosaic

Suspect agent: Apple mosaic ilarvirus

All of the following symptoms have been attributed to the “plum” strain of peach mosaic; the severe strain of the virus infects apricot without exhibiting symptoms.

Leaves show chlorotic mottle, ringspots, or bands encircling or running parallel to the veins. Leaves are often cupped or distorted; the shoot internodes are short.

Trees are less vigorous; fruit yield decreases. Fruits are frequently scorched by sunlight.

Summary: Nemeth 1986


Almond Mosaic

Causal agent: Prunus necrotic ringspot ilarvirus

Symptoms are generally thought to be caused by the “plum” strain of peach mosaic, whereas the severe form of the same pathogen causes symptomless infections.

Leaves experience chlorotic flecks, vein feathering, interveinal spots, or diffuse band, which run parallel to the midrib.

The outer green hull of fruits may develop bumps; but it neither affects the quality or quantity of the yield.

Summary: Nemeth 1986


Cherry Mottle Leaf

Causal agent: Cherry mottle leaf virus

Leaves develop irregular chlorotic mottle and distortion, especially on those that are terminal. Puckering, tattering, shot-hole, and smaller than average leaf size vary according to the cultivar and severity of the virus strain. High temperatures may mask the symptoms. Die back of shoot ends and leaf fall does not occur. Because of the lack of terminal growth and shortened internodes infected trees can appear rosetted.

Fruits of only severely infected and non-tolerant tree exhibit symptoms; ripening is delayed and while no deformations appear, they are small and flavorless.

James 1993 reported monoclonal antibody specific to mottle leaf virus reacted with peach mosaic virus in ELISA assay and Western blot analysis.

Key Reference: James 1993
Summary: Nemeth 1986


Fruit Tree Testing

Virus Testing The Virus Diagnostic Lab offers three testing panels for Fruit Trees Complete Virus Testing Canary Virus Testing Targeted Virus/Disease Testing See below for viruses and viral-like pathogens listed for each commodity. A signed CPCNW-VDL Testing Agreement must be submitted with the plant material to be tested. Plant material and testing agreement can be… » More ...