|Table 3. Reddish/Purplish coloration (anthocyanescent markings) in Plumeria caused by
means other than virus
|According to DPV web, the FrMV transmitted by mechanical inoculation not involving a
vector. FrMV hardly spreads in plumerias especially in the wild probably due to the lack
of natural carrier for this particular virus. Gaining popularity in the past two decades,
plumeria has been vegetatively propagated in mass for sale. Many growers did not take
any precautions when taking cuttings or making grafts. Viral-contaminated cutting tools
used in grafting and pruning become the most common means of FrMV transmission.
Unfortunately, it is how this particular virus spreads rapidly and covertly in plumerias,
especially in Thailand and recently in the plumerias exported to the US and the rest of the
world. Nowadays, its symptoms are commonly seen in plumerias which are sold in the
markets in a number of countries. Some virused plumerias may look normal, but the
symptoms generally appear in a later stage. Thus it is important to address this issue to
increase growers' awareness, to keep the virus under control, and to save all great
plumeria cultivars from being infected.
In an attempt to keep the whole plumeria collection virus-free, newly acquired plumerias
first should be isolated over a period of time to observe or check (test) for the presence
of virus. All FrMV-infected plants should be separated from the rest of collection and/or
destroyed. Using a sterilized cutting tool is also the key to preventing the spread of the
FrMV, which may be present in the plumeria trees growing in the garden, to the rest of
the collection. My routine practice of pruning plumerias in the garden is to carry as many
sterilized knives as possible with me and use only one knife per plumeria plant. They are
then sterilized in boiling water for further use.
Plumerias with the virus should not be allowed to be registered as a new cultivar
based upon its appearance of the flowers with the color break. It is just a diseased
plant, not an innovative one.
|Based upon field/laboratory tests and observation of infected plumeria plants from
various places for a number of years, it comes into a conclusion that Frangipani Mosaic
Virus has a minimal effect on the growth and the health of most plumerias with the
exception of severe cases in a few cultivars. Its symptoms may include, e.g., leaf
malformation, mottled leaf, and/or non-uniform splash or color break (CB), especially on
the petals. Some plumeria trees appear normal with only an occasional CB on the petals,
which is attractive to some people. From my point of view, however, the color break is
unacceptable since it distorts the original colors of flowers. In addition, unlike other
diseases, it is incurable, and the virus that resides in the infected plant may accidently
spread to other plumeria trees somehow, and finally, the whole collection may all be
|Viruses are one of infectious pathogens. Like other plants, plumerias can be infested
with viruses. The particular types of viruses such as Frangipani Mosaic virus (FrMV)
found in infested plumeria may cause discolorations and/or distortions in leaves and
flowers and stunt the plant growth. The symptoms are highly variable, depending
on the variety and the environment. Knowing the nature of FrMV (especially viral
transmission) as well as using precaution when handling the plants are the key steps in
preventing it from spreading. FrMV and its symptoms found in plumeria in Thailand are
emphasized on this page. Coloration markings caused by FrMV and by other means are
also mentioned here.
|Table 1. Symptoms in Plumeria (flower, leaf and petiole) caused by Virus
Note: FrMV Splashes is due to the over accumulation of anthocyanin pigments in flower petal and/or leaf of virused plumerias.
|Figure 2. The original color of virus-free
|Figure 1. Vishanu Gold infected with FrMV
Frangipani Mosaic Virus (DPVWeb)
FrMV (Plant Viruses Online)
FrMV testing service - AC Diagnostics
FrMV testing service - Lynch Diagnostics
The complete genomic RNA of FrMV
*FrMV is transmitted primarily through cutting or trimming the plants. Contact of the infected
plant's sap with sap of a healthy plant will infect the new plant. This can happen whenever cuts are
made and the cutting/grafting tools, hands or workbenches are not disinfected afterwards. After
infection with a virus, it enters the vascular system of the plant, and the virus particles (virions) are
formed and transported through plasmodesmata (microscopic channels bettween cells). In the
process, they spread from the infected cell to neighbouring cell(s) (where more virions are
replicated), and move from one part of the plant to the next, and eventually colonize the whole
plant. The first sign of symptom in plant may take months or years to appear (depending upon
plumeria cultivar, and plant and environmental conditions).
*FrMV resides in infected plant throughout the plant's life. The disease is incurable. Cuttings
taken from an infected plant are infected even if no symptoms are immediately exhibited by the
cuttings. The only area in the infected plant that virus can not enter is meristem. Meristem-tip
culture may be applied to get a new plant with free of virus.
*FrMV does not transmit through seed, resulting in absence of virus in seedling. Like all
plumerias, the seedling can be infected with FrMV at any age with poor cultural and sanitation
FrMV may lie dormant within a cell, and the period of the latency in some plumeria cultivars can
span for a long time without any symptoms on their flowers and leaves. The mechanism to reverse
the latent state is quite complex involving the interaction between the virus and its plant host. The
virus is also able to occasionally reactivate via external activators (i.e. stress or the change in
environmental conditions or any other unknown factors) to cause the symptoms to reappear.
*Heat is one of the many factors that can put a lot of stress on a plant, and provides favorable
condition for FrMV residing in the plant to grow. FrMV is more active and replicates quickly at a
relatively high temperature (best at 30-35C or 86-95F) but at a slower rate when temperature is
outside (lower or higher) of its optimal growth range. Although the extreme and prolonged heat
(e.g. 100+F) is not the best condition for FrMV to grow, it can put a lot of stress on the plant host.
It is important to note that it is the VIRUS (not HEAT or other external activators) that is
responsible for these unique "viral symptoms" in the virused plumeria plant. The other words, only
the plumeria plant infested with the FrMV can exhibit the "viral symptoms" when the condition(s)
is right, but the non-virused plant never ever does.
*Grafting (especially bud grafting) is another factor that causes a lot of stress on a plant. If either
rootststock or scion used in grafting is from virused plant(s), the entire graft is infected. The viral
symptom likely appears on emerging leaves of the newly grafted plant. Again, it is the VIRUS (not
GRAFTING) that is responsible for the viral symptom on the leaves.
The symptoms of viral disease result from the immune response to the virus, which attempts to
control and eliminate the virus from the plant and from cell damage caused by the virus.
*FrMV replication causes a change in color pattern of pigmented flower/leaf by intensification and
overaccumulation of epidermal anthocyanin pigments in the petals/leaves (anthocyanescene). (Note:
Anthocyanescence is the development of reddish/purplish hues within the context of normal coloration by the
accumulation of anthocyanin.)
*Looks for the virus lesions on a newly emerging leaf and flower. These are where the symptoms
first reveal themselves (before evolving further with leaf or flower age) and are a strong indication
of FrMV evidence.
*FrMV affects different plumeria cultivars/species in different ways, so it is impossible to give a
definitive description of symptoms. Besides plumeria cultivars, the symptoms may vary with plant's
parts (e.g. flower, leaf, petiole and etc.) and viral strains and environmental conditions. Yet there
are some common characteristics among infected plants; including irregular mottled/splotchy
markings or dark striations of various sizes and shapes on the leaves, and non-uniform dark
red/moroon splashes (color breaks) of various forms and size unevenly/unpredictably distributed on
the flower petals and non-consistent patterns from flower to flower (Table 1 and 2).
Depending on how people view it, the color breaks on flower petals may look like a "dark
red/maroon paint splatter" in painted pictures or "blood splatter" at a crime scene in J105 plumeria
cultivar, or "blood or red paint bleeds" in watercolor in Bali Whirl cultivar. Unlike flowers, leaves
can stay on the tree for a longer time; therefore, the viral mottled markings or the dark striations
may change in size, color and shape as the leaves expand and the symptom progresses into
surrounding tissue of the leaves. The color of mottled makings generally fades when the leaves
mature and age.
*Infection does not always result in visible symptoms at all time. In case of having visible
symptoms, they may exhibit only on either flowers or leaves or disply on both flowers and leaves at
the same time. In case of Plumerias (eg. P. alba) with pure white flowers (no anthocyanin
pigment), the symptom only appears on leaves.
*FrMV does not kill plumeria plant. Most virused plumerias are apparently normal with symptoms
which occasionally appear on a few flowers and/or a few leaves. Some cultivars may frequently (or
hardly) exhibit symptoms especially the color breaks on flower petals. However, the growth of a
few cultivars may be severely impaired by FrMV infection.
|FrMV and Symptoms in Plumeria
|Table 2. Unique Symptoms caused by Virus in some Plumeria Cultivars
Note: FrMV splashes vary in appearance size and shape, and romdomly and unevenly exhibit on flower petals and/or leaves,
and have non-consistant pattern from flower to flower (and leaf to leaf).
|Apart from the FrMV, the levels of anthocyanin accumulated in some particular parts of
plumeria flower and leaf can also be influenced or caused by other factors. The
reddish/purplish coloration being formed is generally a common plant response (associated
with plant's physiological functions) to heat/sunlight or UV-B radiation, nutritional
deficiencies/excesses, plant abnormalities, chemicals, insect feeding, plant pathogens
(including virus), wounding and etc. (Table 3). The anthocyanescent markings formed
after being exposed to these factors are quite different in forms, sizes and shapes, and to
the untrained eye they may be mistaken for other kinds of markings such as natural
splash, chimeral splash (see Splashes in Plumeria) and those caused by FrMV (Table 1 and
|Virus causing Color Break in Plumeria in Thailand
|Splashes caused by means other than FrMV