Fishtail palm (Caryota mitis) is one of the important palms growing trees all over the world including Pakistan. Other names are rabok, tukas or malay. It has twice subdividing leaves. Usually calling fishtail palm because of shape of leaflets.
Fishtail palm is one of the important palm trees across globe. Rabok, tukar, malay are other local names of fishtail palm. Because of its leaf shape as fishtail people call it fishtail palm. It’s height may reaches 8 m tall.
It has unique way of flowering; first of all flowering occurs in the form of clusters from top of a mature palm, later on emerge underneath and so on. Flowers are small having separate female and male flowers. Fruit of fishtail palm is round in shape and green color turning blackish red. This palm propagated through suckers growing from the base.
There are nearly 13 species native to Asia (India, China, Indonesia, etc.), the South Pacific and Northern Australia. The widely known species is Caryota urens. Peoples are using flowers of Caryota urens to make palm wine and also an unrefined sugar (jaggery).
In the US state of Florida, Caryota mitis is an invasive introduced species. It belongs to family Arecaceae with bipinnate foliage may grow in mountainous areas and also adapted to warm mediterranean climates as well as tropical and subtropical climates. In Hawaii, C. mitis is extensively grown in landscapes and is sometimes exported for use in as houseplants or interiorscapes.
Uses of fishtail palm
Extraction of edible starch is achieving through stem processing, rest of palm is hear eating. It is also tapping for obtaining sap which is by fermentation to make toddy or processing into palm sugar.
Fishtail palm is utilizing as tinder to start a fire by using the fuzz of young leaves and also using in construction. The fibers from the leaf sheath are using to make into rope, leaves and weaving into household stuffs. Beads are also making from seeds.
However, the whole plant and fruit may cause severe burning because of presence of minute needle like crystals.
Insects pests and diseases
Fishtail Palms are prone to serious problems causing by insects and diseases. All of which decrease the production by 30 percent. Under high rainfall or overhead irrigation it is susceptible to damage causing by scale insects, spider mites, nutrient deficiencies and diseases like fungal leaf spots, bacterial leaf blights, lethal yellowing etc.
Leaf spot disease of Fishtail palm
Fungal pathogen like leaf spot disease causing by Alternaria species can also infect fishtail palm. The most frequently occurring species include Alternaria alternata, A. longipes, A. dianthi, A. triticina, A. helianthi etc. Among these A. alternata is most common causing leaf spot disease.
A. alternata produces variously shaped lesions on leaf surface of fishtail palm. Initially spots small, chlorotic, light brown and sometimes became necrotic having a chlorotic halo. When spots are mature they become brown to black in color, combining to form large irregular necrotic patches and leading to leaf death.
Leaf spot diseases of ornamental plants are frequently occurring, these are prevalent in relatively cool, wet spring weather and water present on leaf surface is essential for infection.
Bacterial leaf blight of fishtail palm
Plant pathogenic bacteria also infect fishtail palm causing a leaf striping blight disease of leaves. The typical disease symptom includes visible darkly colored stripes along as well as around the leaf veins. The disease is causing bacterium name Acidovorax Avenae Subsp.
Initial symptoms are small, water-soaked spots and light yellow to light brown stripy areas running around and along leaf veins. The stripy lesions range from 1-2 mm wide and extend up to the whole length of the leaf under effect of infection. The hydathodes present at leaf tips or margins serve as initial entry point for pathogen.
Lethal yellowing (LY) is caused by Candidatus Phytoplasma palmae which is cell wall less bacteria belongs to class Mollicutes. The premature drop fruit is the first obvious symptom on mature palms. The next symptom on mature palms is foliar discoloration or foliar yellowing when younger leaves are under attack they become reddish brown to dark brown or gray color rather than a characteristic yellow.
Scale insect and red spider mites are of serious concern, especially when fishtail palms are used indoors. Fishtail palm is usually attack by diamond scale insect (Phaeochoropsis species) destroy chlorophyll and create brown dead areas.
- Avoid overhead irrigation.
- Irrigate in the morning rather than evening.
- Protect the plants from frequent rainfall and kept under cover.
- Use copper-containing or antibiotic pesticides as preventive sprays.
- Provide good aeration around plants to allow leaf drying.
- Avoid transplanting diseased plants into landscapes.
- Chemical control of lethal yellowing is achieving by application of oxytetracycline HCL antibiotic by administration of liquid injection into the palm trunk.
Current developments for the management of palm diseases in Pakistan
Higher Education Commission (HEC) is funding a project titled “Etiology and integrated management of declining perennial ornamental plants” is being run by Dr Imran ul Haq in Fungal Molecular Biology Laboratory, Department of Plant Pathology, University of Agriculture Faisalabad.
The project aims to identify the diseases of various ornamental plants including fishtail palm, lady palm, foxtail palm, wall palm, and alexandra palm etc. Etiology and management of various other diseases is under consideration.
Sooner, there will be complete profile of various ornamental plants diseases with their pathogens and management. This literature will publish in both English and Urdu, to help the farmers, gardeners and nursery growers to combat the emerging issues of ornamental plants.
The management of diseases of ornamental plants is essential. Because ornamental plants are good as decorative plants for beatification. So these must be healthy and disease free. So that, we can place them outdoor as well as indoor for landscaping.
Although some research work is going on the certain diseases of fishtail palm. But in spite of ongoing research, still there is little information on the etiology and diseases management.
Recently, a new emerging disease is observing in commercial nurseries, landscape areas, green belts along the roads, home gardens, lawns and parks. So the aim is to find out the resistant sources of perennial ornamental plant. Another target is formulation of integrated disease control strategies for sustainable management of the problem. It will keep the environment safe and healthy to protect the ornamental industry and growers from big loss.
This article is jointly written by Suleman Azmat, Dr. Imran ul Haq, Rana M. Sabir Tariq, Shahid Javed and M. Usman.