Virus Diseases of Perennials

The viruses that affect perennials are for the most part the same viruses associated with annual bedding plant production.

The virus that is most commonly associated with problems in perennials is cucumber mosaic virus (CMV). This is no surprise because CMV is the most common plant virus in the world. The symptoms associated with CMV are as varied as the differing plants it infects. The symptoms associated with CMV infection can range from mild to severe depending on the host. Creeping Bugle Weed (Ajuga reptans) is commonly infected with CMV. Of the 500+ samples of the variety "Royalty" we have tested at Ohio State, 100% were infected with CMV. Symptoms of CMV range from a mild mosiac or mottleing of the leaves and flowers to bright yellow ring spots and severe plant deformation (Figure 1). In most cases CMV will not kill it's host, however close attention must be payed to fact that aphids can move this virus from plant to plant very easily. Growing perennial hosts that are affected by CMV can serve as a potential source of the virus for other crops such as vegetable transplants and annual bedding plants (Figure 2) (Figure 3).

Another virus that can be commonly associated with herbaceous perennial production include tobacco mosaic virus (TMV). Symptoms primarily associated with this common virus are mosaics and to a lesser extent, ringspots. TMV can be found in the perennial host Epimedium sp. Since TMV can be easily transmitted from plant to plant by touching and handling of infected leafs and stems, and that TMV can infect a wide variety of hosts, including most species of the plant family Nicotiana, it is recommended that plants infected with TMV not be handled and removed from the production area as quickly as possible. Infected plants should be destroyed.

There are a variety of other viruses that infect perennials (Figure 4) (Figure 5). Some of which have been identified and some of which have not. Caution should be taken with all plants suspected of virus infection in not allowing these perennial hosts to become a source of virus for other crops. Close attention should be payed to plants that express the types of symptoms discussed above. Also since insects are the primary method of virus spread in the production facility and in the garden, insect scouting using sticky traps should be a vital part of any perennial production program.