Key warning symptoms

• Mosaic
• Spots
• Line patterns
• Veinbanding
• Mottle

Virus-infected roses may show no symptoms, or different symptoms in different parts of the same plant. Plants can also be infected with more than one virus.

An infection by Prunus necrotic ringspot virus, Apple mosaic virus Arabis mosaic virus is referred to as Rose Mosaic Complex and is usually responsible for rose mosaic disease. Apple mosaic virus and Prunus necrotic ringspot virus are the pathogens we most often find in rose samples.

Rose mosaic symptoms vary greatly, and can include chlorotic line patterns and spots--yellowish or light green because of lost chlorophyll--and mottled patterns. Although some plants may not show obvious symptoms, infected plants are less vigorous and more likely to die in the winter than healthy ones. Both viruses are spread by grafting. Strawberry latent ringspot virus, spread by nematodes in the soil or by propagating infected plants, can cause yellow flecks on leaves or stunted or distorted leaves. Some cultivars may be symptomless.

Tests for Apple mosaic virus and Prunus necrotic ringspot virus are frequently performed as part of large-scale rose screening programs. For best results, first discard plants showing rose mosaic symptoms, then send samples from the plants that appear healthy.