The coconut palm, Cocos nucifera, is an erect palm in the family Arecaceae which is grown its fruits, used primarily for the extraction of coconut oil for use in cooking. The coconut palm has an erect or slightly curved stem which grows from a swollen base. The stem is smooth, light gray in color and has prominent leaf scars. The stem is topped with a crown of 60–70 spirally arranged leaves. The leaves are long (up to 7 m/23 ft), pinnately divided and composed of 200–250 tapering leaflets. The inflorescence is a spike produced at the leaf axil with 20–60 branches, each with a female flower at the base and many male flowers. The fruit is a drupe containing a single seed. It is ovoid in shape with three sides divided by ridges. The exocarp and the mesocarp make up the husk of the coconut. The seed is protected by a thick, stony shell, or endocarp, and is partially filled with a liquid known as coconut water. The edible endosperm is white and meaty and can be between 1.0 and 2.5 cm (0.4–1.0 in) thick. Coconut palms can reach a height of 30 m (98 ft), produce up to 75 fruits a year, and live for up to 90 years. The origin of the coconut is unknown although the center of genetic diversity lies in Southeast Asia.
Coconuts are primarily cultivated for their oil. The oil is extracted from the endosperm and is used in cooking. Low grade oils are used in the production of soaps. The endosperm can be consumed fresh or dry and is commonly grated for use in baking. Young coconuts, termed waternuts, are commonly sold in tropical resorts, where the liquid is drunk directly from the shell. Coconuts may also be used to produce coconut milk by squeezing the liquid from the grated endosperm. Coconut milk is popularly used in many dishes from Southeast Asia.
The coconut palm is a tropical plant and is generally grown in humid, tropical regions. It grows optimally in areas with an annual mean temperature of 27°C (80.6°F) with in excess of 2000 hours of sunlight per year. The palm will thrive in a wide range of soils from sand to clay as long as they are well draining and well aerated with a pH between 4.3 and 8.0. Although palms are often found growing on sandy beaches, they can be successfully grown inland but will not tolerate freezing temperatures.
Coconut palms are propagated exclusively from seed. The seeds are ready for planting when the coconut milk can be heard sloshing around inside the seed when it is shaken. Seeds are germinated by planting in seed beds before transferring to a polythene bag or nursery beds after germination. Seeds should be planted on their sides in a shallow hole with enough soil to cover about one third of the seed. The seed should be watered regularly to prevent it drying out. Germination usually occurs after about 3 months but may take up to 6 months.
Coconut seedling can be transplanted from 6 months onwards or transferred to pots and grown further in the nursery. Trees require a wide spacing and are typically planted 8–9 m (26–30 ft) apart allowing a further 8–9 m (26–30 ft) between rows. Dwarf varieties can be spaced closer together and are typically planted 7.5 m (25 ft) apart allowing another 7.5 m (25 ft) between rows
Chlorosis of youngest open leaves; leaves rapidly turning necrotic; necrotic spots on leaf bases; unopened spear leaves can be pulled away from the plant easily; removal of unopened spear leaves reveals soft, pink-red tissue with foul smell; leaf necrosis spreading through central crown leaves; woody parts of plant may have water-soaked, pink lesions with dark borders; infected inflorescences abort nuts.
Palms between 14 and 40 years old most susceptible; disease occurs in all coconut growing regions; diseases emergence favored by high rainfall.
Control of the disease is reliant on good sanitation practices and the use of appropriate systemic fungicides; remove all infected debris and dead trees from plantation and destroy; irrigate trees early in the day to allow surfaces to dry off during the day.
Newly formed nuts more rounded than in previous years; nuts exhibit scarring on the surface; chlorotic spots on leaves; stunted inflorescences with tip necrosis; leaves begin to decline in size and number; death of palm.
No vector has been identified.
There is currently no known method of controlling the disease.
Damged and/or aborted flowersd; sunken necrotic lesions and scars on nuts; young nuts may exude gum (gummosis) and die; many nuts fall from tree; adult insect is a brown-red with well-developed wings; nymphs are brown-red or green in color with long antennae and feed at the calyx of the nut
The coconut bug is one of the most damaging pests of coconut in Africa; just two bugs per palm can cause severe damage
Natural enemies of the coconut bug include weaver ants, conserve bushes and trees around plantation which are habitats for weaver ants or intercrop with mango, guava or citrus which are attractive to weaver ants; connect canopy with ropes or sticks to allow weaver ants to move between trees
Some varieties which have the disease may show no symptoms, others exhibit partial yellowing of leaves which begins to spread to leaf tip; necrosis of petioles causing leaves to die and hang from palm canopy
Transmitted by leaf hoppers
The larvae feeds on under surface of leaves. Usually they found protected by silken web. Initially they feed on the lower epidermis leaving the upper epidermis intact. The larvae often fold two sides of leaflets by a silken thread and feed inside. The later stage larvae feeds on both upper and lower epidermis of leaves. Severe infestation leads to skeletonization of fronds.
The insect is quite common in high wind areas.
Encourage natural enemies in the orchard.
V-shaped cuts in palm fronds or holes in leaf midribs caused by beetles boring into crown to feed; adult insect is a large black beetle with a curved spine on its head; larvae are creamy white grubs with brown heads and 3 sets of prolegs at the anterior (head) end.
Beetles are nocturnal and fly at night; also a damaging pest of oil palm.
Destroy any decaying logs in plantation by chopping and burning to kill any larvae that may be inside; remove any dead trees from plantation and destroy by burning; plant a cover crop to deter egg laying by females as they do not lay eggs in areas covered by vegetation; hooked wire can be used to extract larvae that are boring into young crowns.
Pale yellow spots on leaves; entire leaves yellowing; leaves turning brown and dropping prematurely; adult insect is a flattened oval, resembling a scale, which is red-brown in color.
Insect also attacks other crops such as tea and mango.
May be possible to control coconut scale by pruning infested parts of trees and destroying by burning; chemical control may be necessary.
The mites suck sap from young nuts. Generally they feed on meristematic zone, i.e., the area which is covered by perianth. The infestation starts very early. As the nut develops the feeding leaves brown fissures that extending down from the perianth. The nut becomes small and distorted.
The mites spread through the wind. It causes yield loss from 30 to 60 per cent.
Provide proper fertilizer and water for trees to withstand mite damage. Encourage natural enemies of mite in the orchard. If infestation is severe, apply suitable insecticide by root feeding or stem injection.
Older fronds turning yellow and gradually wilting and drooping; fronds collapsing and dying; internal tissue of lower stem discolored; overall reduction in vigor.
Fungi may enter through wounds on trunk or pruning wounds.
Spacing trees widely limits the chance of infection through root grafts; avoid damaging tree trunks with tools and machinery; remove any dead or severely damaged trees from plantation immediately, including any that have been killed by natural processes; if a site is known to be infected with the disease, the ground should be fallowed for at least 1 year prior to a new plantation being established.
Small, yellow-brown spots on leaflets which develop gray centers and dark green borders; lesions coalesce to form large necrotic patches; tips of leaflets turning gray; canopy has blighted appearance.
Fungi will colonize young, wounded or weakened tissues; disease emergence favored by high rainfall and high humidity.
Disease usually only merits control in coconut nurseries as infection of mature coconut palms are rare; appropriate broad spectrum protective fungicides should be applied.
Oldest leaves of palm turning yellow and wilting; reddish-brown rot in bole tissue; destruction of root system
Some grasses such as Bermuda grass have been reported as alternative hosts fro the fungi
Any infected trees must be uprooted and burned; area can only be replanted once soil is treated for the disease
Premature dropping of fruit; fruit with brown-black water-soaked appearance; necrosis of inflorescences; flower stalks turn black; lower, older leaves turning yellow; entire crown turning yellow; yellow leaves turn brown, dry out and hang from canopy.
May be transmitted by leaf hoppers.
The most effective method of managing the disease is to plant resistant coconut varieties such as Malayan dwarf or Maypan; antibiotic treatment is effective but not usually practical for large scale plantings.
Flattened oval to round disc-like insect covered in waxy substance on tree branches; insects attract ants which may also be present; insect colony may also be associated with growth of sooty mold due to fungal colonization of sugary honeydew excreted by the insect; symptoms of direct insect damage not well documented but trees may exhibit symptoms of cocoa swollen shoot (see disease entry).
Insects have a wide host range; often tended by ants which farm them for their sugary honeydew secretions; transmit Cocoa swollen shoot virus.
Mealybugs can potentially be controlled by natural enemies such as lady beetles but are commonly controlled using chemicals; chemical pesticides may also decrease populations of natural enemies leading to mealybug outbreaks.
Nuts falling prematurely; withering inflorescences; yellowing leaves which then turn brown; orange to red-brown ring of discoloration when a cross section is taken of lower stem.
Nematode spread to palms via American palm weevils and sugarcane weevils.
If a tree becomes infected it should be removed and destroyed; control of the disease is currently limited to efforts to control the weevil which transmits the nematode to the palms.
Soft, yellow rot on trunk; affected areas are dark and turn black as they mature; a reddish-brown liquid may ooze from rotting regions and spill down trunk.
Fungi enter the trunk through wounds.
Avoid wounding palms with machinery and tools to reduce disease incidence; disease can be controlled with applications of the fungicide benomyl where registered; infected trees should be removed and destroyed as soon as possible.
Broschat, T. K. & Crane, J. H. (2011). The Coconut Palm in Florida. University of Florida IFAS Extension. Available at: http://edis.ifas.ufl.edu/pdffiles/MG/.... [Accessed 13 November 14]. Free to access.
CABI Crop Protection Compendium. (2014). Cocos nucifera datasheet. Available at: http://www.cabi.org/cpc/datasheet/11788. [Accessed 13 November 14]. Paid subscription required.
Chan, E. & Elevitch, C. R. (2006). Cocos nucifera (coconut). Species profiles for Pacific Agroforestry. Traditional Tree Initiative. Available at: http://www.agroforestry.net/images/pd.... [Accessed 13 November 14]. Paid subscription required.
Duke, J. A. (1983). Cocos nucifera L.. Handbook of Energy Crops. Available at http://www.hort.purdue.edu/newcrop/du.... [Accessed 13 November 14]. Free to access.
Elliott, M. L., Broschat, T. K., Uchida, J. Y. & Simone, G. W. (2004). Compendium of Ornamental Palm Disease and Disorders. American Phytopathological Society Press. Available at: http://www.apsnet.org/apsstore/shopap.... Available for purchase from APS Press.
guttaprasadg I'd like to know about the requirement of micronutrients for application to 4 years old plantation - the plants are not in bearing, they will be bearing fruit next year.