Dasheen Mosaic of Edible and Ornamental Aroids - College of ...

Dasheen Mosaic of Edible and Ornamental Aroids 

Scot C. Nelson 

Department of Plant and Environmental Protection Sciences 

This publication covers dasheen mosaic diseases of 

Colocasia, Xanthosoma, and Philodendron and 

discusses some integrated management practices that are 

useful for its control in severely affected plant species. 

Dasheen mosaic is an important and conspicuous viral 

disease of ornamental and edible aroids throughout the 

Pacific and worldwide. The pathogen, dasheen mosaic 

potyvirus (DsMV), was first recorded from dasheen 

(Colocasia esculenta (L) Schott) in 1970. Today, DsMV 

is a common and widespread pathogen of the aroids 

Aglaonema, Caladium, Colocasia, Dieffenbachia, 

Philodendron, Xanthosoma, and Zantedeschia. DsMV 

is especially threatening to aroid nurseries where plants 

are grown from cuttings, corms, or bulbs rather than as 

virus-free materials derived from tissue culture. 

Before the advent of tissue-culture technologies, 

DsMV presented major problems for ornamental species 

in the Araceae, causing particularly severe reductions in 

plant growth and yield for species of Caladium, Dieffenbachia, 

and Philodendron. The use of tissue-cultured, 

virus-free plantlets helped to reduce or eliminate the dasheen 

mosaic problem in commercial nurseries. However, 

the disease can still enter aroid production houses and 

cause losses, and it can thereafter be spread mechanically 

by plant sap during further cutting of plants and 

their vegetative propagation. 

Recently, a commercial aroid nursery in Hawai‘i 

reported odd symptoms on a Philodendron variety that 

arrived in Hawai‘i from Florida as tissue-cultured plants 

and thereafter was grown and vegetatively propagated by 

stem cuttings at the nursery. The grossly distorted foliage 

of the symptomatic plants tested positive for DsMV, 

and the entire stock of diseased plants was subsequently 

destroyed by the grower to prevent further disease spread. 

This suggests the need for a re-evaluation of the dis- 

Plant Disease 

Aug. 2008 

PD-44 

ease in Hawai‘i at this time and a discussion of DsMV 

transmission and cultural management for ornamental 

aroids. 

Susceptible aroids have a global distribution. The most 

common host for the virus in Hawai‘i, Colocasia esculenta 

(taro, dasheen), is thought to be native to India; it is widely 

cultivated throughout the tropics for its edible root. 

In recent years, new strains of DsMV have been reported 

for the first time in two genera of orchids. In French 

Polynesia a severe strain of DsMV attacks some edible 

aroids including C. esculenta, causing severe symptoms 

from which plants fail to recover or compensate to produce 

normal yields. In Hawai‘i, however, a milder strain 

of DsMV is widepsread among taro plants and appears to 

cause little reduction of corm yield for most commercial 

taro types, and it therefore usually warrants no management. 

However, some taro cultivars in Hawai‘i appear to 

be much more susceptible to DsMV. 

The majority of taro plants in Hawai‘i are probably 

infected with DsMV. In a survey by CTAHR’s Dr. John 

Hu and associates in the early 1990s, DsMV was detected 

in 14 of 15 commercial taro fields, in all 9 commercial 

taro cultivars surveyed, and in 163 of 186 taro accessions 

indexed. They developed and used indirect enzymelinked 

immunosorbent assay (ELISA) procedures to 

detect DsMV. 

In unpublished research, CTAHR’s Dr. Susan Miyasaka 

and associates established a field planting of DSMVfree 

taro on the island of Hawai‘i in the 1990s. The taro 

plants were first cleared of DSMV virus infection by 

tissue culture. After planting, the taro was monitored 

over time for expression of dasheen mosaic symptoms. 

Within approximately 3–4 months, virtually all of the 

taro plants displayed the typical symptoms of the disease, 

and many of them were expressing the symptoms even 

Published by the College of Tropical Agriculture and Human Resources (CTAHR) and issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation 

with the U.S. Department of Agriculture. Andrew G. Hashimoto, Director/Dean, Cooperative Extension Service/CTAHR, University of Hawai‘i at Mänoa, Honolulu, Hawai‘i 96822. 

An equal opportunity/affirmative action institution providing programs and services to the people of Hawai‘i without regard to race, sex, age, religion, color, national origin, ancestry, disability, 

marital status, arrest and court record, sexual orientation, or status as a covered veteran. CTAHR publications can be found on the Web site .

UH–CTAHR Dasheen Mosaic of Edible and Ornamental Aroids PD-44 — Aug. 2008 

more severely than expected. The presence of a DsMV 

vector, the green peach aphid (Myzus persicae), was 

confirmed in the taro field (Susan Miyaska, personal 

communication). 

Some speculate or believe that certain Hawaiian taro 

cultivars are, or were, much more susceptible to dasheen 

mosaic, and that what remains of the original population 

of Hawaiian taro varieties is perhaps more tolerant of 

the disease and those varieties that have been become 

extinct or have been lost from taro collections may have 

been more intolerant of DsMV infections. 

It is commonly reported that DsMV does not cause 

substantial yield loss to taro, and that is still a prevailing 

opinion for this taro disease in Hawaii. However, 

depending on the host-virus strain combination and the 

location, DsMV can severely impact yields of the edible 

aroids Colocasia and Xanthosoma in the Pacific. Symptoms 

on the more susceptible varieties include chlorotic 

feathering patterns on leaves and severe leaf curling and 

malformations. 

Hosts 

Most of the known hosts of DsMV are among edible 

and ornamental species of the Araceae (aroids). Worldwide, 

DsMV infects least 16 genera in this family and is 

widespread among the edible Colocasia, Xanthosoma, 

and Cyrtosperma species and among the inedible ornamental 

genera Aglaonema, Caladium, Dieffenbachia, 

Philodendron, and Zantedeschia. 

Aroids are plants of the family Araceae; they have 

small flowers massed on a spadix surrounded by a large 

spathe. Aroids are widespread globally and very abundant 

in the tropics. The inedible aroids are important 

ornamental home and garden plants. The edible aroids 

are tremendously important to diets of indigenous tropical 

societies as staple starch-food crops that are capable 

of withstanding the damaging effects of tidal waves and 

hurricanes. Taro, perhaps the most widely grown of the 

edible aroids, is a perennial herb consisting of a cluster 

of smooth, heart-shaped leaves, rising a foot or higher 

from underground tubers. In temperate areas it is grown 

as an ornamental plant for its large, glossy leaves. 

In the Orchidaceae, Vanilla tahitensis is a host of 

unique strains of DsMV in French Polynesia and the 

Cook Islands; a terrestrial orchid, Spiranthes cernua, 

hosts a strain of DsMV in the continental United States. 

Hosts of DsMV may be grouped on the basis of their 

symptom expression (Table 1). 

2 

At top, leaf malformation and chlorotic feathering along 

leaf veins are characteristic symptoms of dasheen 

mosaic disease of taro (Colocasia esculenta). Above, 

close-up of the typical feathering symptom on a taro 

leaf. (Photos: S. Nelson)


Symptoms of dasheen mosaic on taro (Colocasia esculenta): pale whitish to yellow to yellow-green patches on the 

leaves, characteristically as featherlike patterns along the veins, especially near leaf margins, and leaf deformities. 

Two or three leaves on a plant may show symptoms, but thereafter normal leaves are produced. 

(Photo at left, W. Nishijima, at right, S. Nelson) 

Feathering symptoms on the underside of a taro leaf (left) may be associated with reddening or necrosis of small 

leaf veins. Leaf malformation of taro caused by DsMV infection (right) may consist of wrinkling and puckering of leaf 

surfaces and leaf margins (Photos: S. Nelson) 

3


Conspicuous necrotic and chlorotic feathering along leaf veins of a dasheen variety (Photo: S. Nelson) 

Symptom expression, infection, and 

disease effects 

There may be some overlapping for symptom expression 

among plant genera; variability in symptom expression 

may depend on the host, the particular strain of DsMV, 

and the environment. For example, when severely diseased, 

Philodendron may exhibit vein clearing that 

resembles chlorotic feathering. Also, symptoms may be 

intermittent or vary seasonally. For taro, two or three 

leaves may show symptoms and then apparently healthy 

leaves are produced, or leaves may alternate between 

asymptomatic and symptomatic on the same plant. 

The pathogen infects leaves, stems, and petioles. The 

disease results in reduced photosynthesis, reduced corm 

size or yield, reduction in leaf number or size, deformed 

leaves, and stunted plants. 

4 

Disease cycle for dasheen mosaic 

Dispersal: DsMV is dispersed by several species of 

aphids, by the movement of infected plants; as infected 

plant sap on pruning tools. 

Inoculation: DsMV arrives at the site of infection (a 

wounded plant cell) in an aphid’s mouthparts or on 

an infested cutting tool. 

Infection: DsMV enters a wounded plant cell either by 

aphid injection or on an infested tool. 

Disease development: Virus particles multiply within 

plant host cells, eventually resulting in symptom 

development. Virus particles move between adjacent 

cells via plasmodesmata and long-distance within a 

plant via the vascular tissues. 

Pathogen reproduction: The virus particles replicate by 

usurping the plant cell’s DNA and protein-synthesizing 

capacities.


Table 1. General types of disease symptoms caused by DsMV and corresponding plant genera that express the 

symptoms. 

Symptoms Susceptible genera 

Systemic mosaic* Aglaonema, Alocasia, Amorphophallus, Arisaema, Caladium*, 

Cyrtosperma 

Systemic mosaic, leaf malformation, epinasty, Cryptocoryne, Dieffenbachia, Philodendron, Richardia, Zantedeschia 

vein clearing, systemic and local necrosis 

Systemic mosaic, leaf malformation, Colocasia, Xanthosoma 

chlorotic feathering along leaf veins 

Leaf mosaic and malformation Vanilla tahitensis 

Systemic mosaic, chlorotic blotching Spiranthes cernua 

*some cultivars of Caladium hortulanum may show feathering along leaf veins. 

Mosaic and veinal feathering symptom on both sides of a leaf of a Hawaiian taro variety (Photo: S. Nelson)


DsMV on Xanthosoma sagittifolium. Left: white feathering symptoms along the leaf veins of X. sagittifolium in Yap. 

The feathering symptom associated with DsMV is typical of Colocasia and Xanthosoma species. The the newly 

emerging leaf (mostly obscured here) is grossly distorted. Right: leaf distortion (puckering) associated with DsMV 

and the white feathery symptom on X. sagittifolium in Yap. (Photos: Craig Elevitch) 

Pathogen survival: DsMV survives as viable virus particles 

within living plant tissues, or for short periods 

of time in association with the mouthparts of aphid 

species or as infested sap on tools. DsMV is unable to 

survive in dead plant tissues or in dead aphids. 

DsMV is transmissible by three methods 

Vectors: DSMV is transmitted by several species of 

aphids, including the green peach aphid (Myzus persicae), 

the cowpea aphid (Aphis craccivora), and the 

melon aphid (Aphis gossypii). DsMV is not transmitted 

by the banana aphid (Pentalonia nigronervosa) or 

by the bird cherry-oat aphid (Rhopalosiphum padi). 

The virus is transmitted in a non-persistent manner. 

6 

Vegetatively: by suckers, corms, or infected cuttings used 

for propagation. 

Mechanically: by plant sap on knives or shears (yet 

DsMV is not transmitted by incidental contact or 

natural rubbing of leaves between plants). 

Note: DsMV is not transmitted by seed or by pollen. 

Integrated management of dasheen mosaic 

Disease management tactics depend upon the crop. For 

taro in Hawai‘i, management of DSMV is generally not 

warranted on most varieties because the disease apparently 

has a negligible effect on corm yields. However, symptom 

expression may be relatively severe on some heirloom 

Hawaiian taro varieties in some environments.


Symptoms of dasheen mosaic on Philodendron: Leaves 

of Philodendron x cv. 'Hope' as a host of DsMV in Hawaii. 

The test kit shows a positive reaction to potyviruses. 

The virus was confirmed by ELISA and PCR. Symptoms 

on this Philodendron include mosaic, green islands, 

deformity, rugosity, epinasty, curling, yellowing and 

vein clearing. The cultural practices used by the grower 

included vegetative propagation of this plant by cutting 

stems with knives or shears. This may have been the 

means for mechanical transmission of DsMV in this case. 

(Photo: Brian Bushe, UH-CTAHR) 

Dasheen mosaic can cause major economic losses 

for ornamental crops such as Philodendron; in this case 

management of the disease is highly recommended due 

to the damaging effects upon the plant foliage. 

IPM (integrated pest management) principles 

• Avoid introduction or transmission of the virus during 

vegetative propagation. 

• Prevent the introduction and spread of this disease on 

new hosts. 

• Control aphids and ants where aphid transmission of 

DsMV is a problem. 

Close-up of adult melon aphids (Aphis gossypii, adult 

apterous females, highly magnified) on a kava (Piper 

methysticum) leaf. Colonies of aphids and ants are 

common on leaves of taro in Hawai‘i. Not all aphids 

found on taro can transmit the virus; for example, banana 

aphids. (Photo: S. Nelson) 

Some variegated aroids do not carry DsMV: Variegated 

Pothos (Epipremnum sp.), showing symptoms of leaf 

mosaic and perhaps yellow veins, and with leaf deformity 

and rugosity due to feeding injury by aroid thrips. These 

symptoms should not be confused with DsMV on other 

aroid hosts. The mosaic symptom is due to genetic 

variegation, not to disease. (Photo: S. Nelson)


IPM tactics 

• Take cuttings or vegetative sprouts from virus-free 

plants only. 

• Prevent mechanical transmission of the virus on knives 

and shears (dip knives in sterilizing solution between 

cuts). 

• Use certified plants from tissue culture. 

• Plant quarantine: intercept diseased plants at point of 

entry. 

• Nurseries should inspect plants upon arrival and before 

shipping to prevent the spread of plant diseases 

in Hawai‘i. 

• Avoid intercropping taro with other susceptible aroids. 

• Avoid using the same knives or blades that are used to 

harvest taro leaves for vegetative propagation of other 

susceptible aroids. 

• Avoid growing taro in nurseries alongside other susceptible 

aroids. 

• Propagate from seed (DsMV is not seed-transmissible). 

• Culture plants from shoot tips. 

• Control the aphid vectors where the disease is causing 

losses. 

To detect the disease, visually inspect all leaves of plants 

for white feathering symptoms (Colocasia, Xanthosoma, 

and some cultivars of Caladium hortulanum such as 

‘Candidum,’ ‘Candidum Junior’, and ‘White Christmas’) 

or mosaics and leaf deformation (Philodendron, Dieffenbachiae, 

Spathiphyllum, and Zantedeschia, for example). 

Ornamental greenhouse-grown aroids may express symptoms 

intermittently or even be asymptomatic. 

When a symptomatic aroid is submitted to the CTAHR 

Agricultural Diagnostic Service Center for virus detection, 

the test consists of one or more of the following: 

• ELISA (enzyme-linked immunosorbent assay) for 

potyvirus 

• PCR (polymerase chain reaction) or DsMV-specific 

ELISA test. 

8 

Diagnostically susceptible host species 

and symptoms 

Philodendron selloum: systemic mosaic, vein clearing, 

malformation. 

Caladium hortulanum, Colocasia spp., Xanthosoma 

spp.: systemic mosaic. 

Dieffenbachia spp.: systemic mosaic, epinasty, systemic 

and local necrosis. 

Philodendron verrucosum: local necrosis; not systemic. 

Zantedeschia spp.: systemic mosaic, malformation. 

Notes 

Taro is also susceptible to at least two other plant-pathogenic 

viruses not yet in Hawai‘i, Colocasia bobone 

disease rhabdovirus (cause of bobone disease) and dasheen 

bacilliform badnavirus (cause of alomae disease). 

The symptoms are somewhat similar in appearance to 

dasheen mosaic, yet more severe mosaic, leaf malformation 

and curling occurs with much more severe effects 

upon plant growth. 

References 

Elliot, M.S., F.W. Zettler, and L.G. Brown. Dasheen 

mosaic potyvirus of edible and ornamental aroids. 

University of Florida, Plant Pathology Circular no. 

384. 

Plant Viruses Online. http://image.fs.uidaho.edu/vide/ 

descr289.htm. 

Farreyrol, K., M.N. Pearson, M. Grisoni, D. Cohen, and 

D. Beck. 2006. Vanilla mosaic virus isolates from 

French Polynesia and the Cook Islands are Dasheen 

mosaic virus strains that exclusively infect vanilla. 

Archives of Virology 151:905–919. 

Jordan, R., M.A. Guaranga, G. Kinard, and S. Lynn. 

Detection and first report of dasheen mosaic virus 

and a second potyvirus infecting the terrestrial orchid 

Spiranthes cernua. Acta Horticulturae (ISHS) 

568:253–260. 

Hu, J.S., M. Wang, R. Reolanei, and S. Meleisea. 1994. 

Detection of dasheen mosaic virus from taro plants in 

the field and in tissue culture. Plant Disease 78:754. 

Hu, J.S., S. Meleisea, M. Wang, M.A. Shaarawy, and F.W. 

Zettler. 1995. Dasheen mosaic potyvirus in Hawaiian 

taro. Austral. Plant Pathol. 24:112–117. 

Kohler, F., F. Pellegrin, G. Jackson, and E. McKenzie. 

1997. Disease of cultivated crops in Pacific island 

countries. South Pacific Commission, Noumea, New


Caledonia. 

Liu, L.J.Y., E. Rosa-Marquez, M. Licha, and M.L. Biascoechea. 

1988. Tanier (Xanthosoma spp.) propagation 

in vitro. Journal of Agriculture of the University of 

Puerto Rico. 72:413-426. 

Neal, M.C. 1965. In gardens of Hawaii. Bishop Museum 

Press, Honolulu. 

Wagner, W.L., D.R. Herbst, and S.H. Sohnmer. 1990. 

Manual of the flowering plants of Hawaii. Bishop 

Museum Press, Honolulu. 

Zettler, F.W., and R.D. Hartman. 1987. Dasheen mosaic 

potyvirus as a pathogen of cultivated aroids and 

control of the virus by tissue culture. Plant Disease 

71:958–963. 

Acknowledgments 

John Hu, UH-CTAHR, for information and a review of 

the manuscript; Wayne Nishijima, UH-CTAHR, for providing 

a photograph; Craig Elevitch, www.agroforestry. 

net, for providing two photographs; Brian Bushe, UH- 

CTAHR, for providing information and a photograph 

and for diagnostic work; Mike Shintaku, UH-Hilo, for 

providing diagnostic work and information; Susan Miyasaka, 

UH-CTAHR, for information and discussion; Fred 

Brooks, UH-CTAHR, for review of the manuscript. 

9

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