Fishtail palm, problems and prospects

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INTRODUCTION:


Fishtail palm (Caryota mitis) is one of the important palms growing all over the world including Pakistan. It is also known as rabok/tukas or malay and it has leaves that are subdivided twice. It is commonly known as fishtail palm because of shape of leaflets. Its 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.


Worldwide occurrence:


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, the flowers of which are used 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:


Its stem is processed; extraction of an edible starch is done and then palms heart eaten. It is also tapped for obtaining sap which isfermented to make toddy or processed into palm sugar. It is used as tinder to start a fire by using the fuzz of young leaves and is also used in construction. Itthe fibers from the leaf sheath are made into rope, leaves are woven into household stuffs and seeds made into beads. However, the whole plant and fruit may cause severe burning because of presence of minute needle like crystals.


INSECT PESTS AND DISEASES:


Fishtail Palms are prone to serious problems caused by insects and diseases, all of which decrease the production by 30%.Under high rainfall or overhead irrigation it is susceptible to damage caused 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:


Fishtail palm may also be infected by fungal pathogen like leaf spot disease caused by Alternaria species. 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.It produces variously shaped lesions on leaf surface of fishtail palm. Initially spots small, chlorotic, light brown and sometimes became necrotic havinga 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 palmcausing 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 caused by bacterium namedAcidovoraxavenaesubsp. avenae. 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 from1-2 mm wide and extend up to the whole length of the affected leaf. The hydathodes present at leaf tips or margins serve as initial entry point for pathogen.


LETHAL YELLOWING:


Lethal yellowing (LY) is caused by Candidatus Phytoplasma palmae which is cell wall less bacterium 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 yellowingwhen younger leaves are attacked they become reddish brown to dark brown or gray color rather than a characteristic yellow.


PESTS:


Scale insect and red spider mites are of serious concern, especially when fishtail palms are used indoors. Fishtail palm is attacked by diamond scale insect (Phaeochoropsis species) destroyed chlorophyll and creating brown dead areas.


CONTROL:


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 achieved by application of oxytetracycline HCL antibiotic administrated by liquid injection into the palm trunk.


Current developments for the management of Palm diseases in Pakistan:


A HECfunded 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, Alexandra palm and fishtail palm etc. Etiology and management of various other diseases is under consideration. No sooner, there will be complete profile of various ornamental plants diseases with their pathogens and management. This literature will be published in both English and Urdu, so as to help the farmers, gardeners and nursery growers to combat the emerging issues of ornamental plants.


CONCLUSION:


The management of diseases of ornamental plants is essential because ornamental plants are used as decorative plants and for beatification. So these must be healthy and disease free so that these can be used as outdoor as well as indoor plants for landscaping.


Although some research work has already been done on the certain diseases of fishtail palm. But in spite of research that has been already conducted still there is little information is available on the etiology and diseases management. The new emerging disease has been observed recently in commercial nurseries, landscape areas, green belts along the roads, home gardens and loans and parks. So the aim is to find out the resistant sources of perennial ornamental plant and formulation of integrated disease control strategies for sustainable management of the problem to keep the environment safe and healthy at to protect the ornamental industry and growers from big loss.


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Published in: Volume 07 Issue 13

Short Link: http://www.technologytimes.pk/?p=15507