An article written by Gerry Mattijetz
of plant viruses occurring in epiphyllums and related species is something that the grower should consider for several reasons. Cactus, especially the opuntia type that epi growers are so fond of using for grafting, are certainly always infected by one or
more plant viruses. In the cactus (opuntia), the virus lives and grows without seemingly producing noticeable symptoms and/or problems for the plant. These viruses live in the plant sap, sometimes in high concentrations.
They are transferred to another plant species by mechanical contact of the host plant sap with the new plant species.
Mechanical transfer can be by insect bite, touching or scraping, or by artificial means, such as grafting, or transfer from cutting tools. Once infected, the new plant cannot be “cured” of this plant virus... it must live
with it, or be destroyed to eliminate the virus. Chemical disinfection of these plant viruses on cutting tools is also not entirely possible.... the viruses can still survive after the application of alcohol or other chemicals. The only effective means to
eliminate viruses from cutting tools, etc is by the heat method.... heating the surface to a high enough temperature to sterilize the surface, thereby destroying the virus. As we can see, doing this to a plant to eliminate a virus is impossible.
Viruses in epiphyllums can manifest themselves in various ways. First, the infected plant is almost always weakened by the presence of the virus;
Slow, poor growth, or difficulty in rooting might be the signs of the presence of a virus. Plants that go “mushy”, or produce mottled, discoloured foliage are probably virused. Also, flowers from a virused plant will often bloom variegated. Although
there seems to be some plants that might do this without a virus present, ( perhaps due to temperature extremes). The likelihood of a virus being present is very great. Although some people might prefer a variegated flower to one that is not, most epi growers
agree that a “clean” flower and plant is desirable.
What can epi growers do to insure their plants are virus free?
Although this can, perhaps, never be
completely certain without extensive laboratory testing, growers can do several things to reduce their chances of growing and SPREADING, plant viruses in their epi collection. First growers should destroy any plant they strongly suspect may be virused. Second
growers should always sterlilize their cutting implements between cuts or use once a cut single edged disposable razors to do their cutting. I use a small hand-held pastry torch to sterilize clippers between cuts of different plants or I use razors. Thirdly,
growers should know that grafting epies onto opuntia or other types of terrestrial cactus to speed up epi growth would certainly ensure that the grafted epi would become infected with a virus. Although epiphyllums can grow with a virus present, and still bloom
and not show symptoms, they would certainly do better without the virus. Of course, one happy note to all of this is.... Plant viruses are NOT passed on into the seeds.......Happy growing
Resource: Epi and Hoya May 2002 Vol.4