Coconut Diseases and their Management

  Coconut: Diseases and Symptoms Bud rot Stem bleeding Leaf rot Tanjore wilt Root (wilt) IPM for Coconut Bud rot Di...

 

Coconut: Diseases and Symptoms

1. Bud rot
2. Stem bleeding
3. Leaf rot
4. Tanjore wilt
5. Root (wilt)
6. IPM for Coconut

Bud rot

Disease symptoms

• Palms of all age are liable to be attacked but normally young palms are more susceptible, particularly during monsoon when the temperature is low and humidity is very high. In seedlings, the spear leaf turns pale and comes off with a gentle pull.
• The earlier symptom is the yellowing of one or two younger leaves. Black spots appear on spindle leaves. Basal tissues of the leaf rot quickly and can be easily separated from the crown. Infection spreads to the older leaves, causing sunken leaf spots covering the entire leaf blade.
• Spot margins are irregular and water soaked, and when the leaves are unfolded the characteristic irregular spots are conspicuous on the blade.
• In the later stages the spindle withers and drops down.
• The tender leaf base and soft tissues of the crown rot into a slimy mass of decayed material emitting foul smell.
• Ultimately the entire crown falls down and the palm dies.

Stem bleeding

Damage symptoms

• Stem bleeding is characterized by the exudation of a dark reddish brown liquid from the longitudinal cracks in the bark and wounds on the stem trickling down for a distance of several inches to several feet.
• The lesions spread upwards as the disease progresses.
• The liquid oozing out dries up and turns black. The tissues below the lesions become rotten and turn yellow first and later black.
• In advanced cases, the interior of affected trunks are hollow due to decay of interior tissues. As a result of extensive damage in the stem tissue, the outer whorl of the leaves turn yellow, dry and shed prematurely.
• The production of bunches is affected adversely. Nut fall is also noticed.
• The trunk gradually tapers at the apex and crown size becomes reduced in chronic cases.

Leaf rot

Disease symptoms

• The first symptom is the appearance of water-soaked brown lesions in the spear leaves of root-wilt affected palms.
• Gradually these spots enlarge and coalesce resulting in extensive rotting.
• As the leaf unfurls the rotten portions of the lamina dry and get blown off in wind, giving a ‘fan’ shape to the leaves.
• Sometimes, the symptom becomes very acute and the spear fails to unfurl.

Tanjore wilt

Disease symptoms

• Initial symptoms of Thanjavur wilt (Ganoderma wilt) start with withering, yellowing and drooping of the outer whorl of leaves.
• This is followed by exudation of reddish brown liquid through cracks at the base of the trunk and oozing spread upward. The tissues on the bleeding spots are soft to touch.
• Decaying of tissues at bleeding point and rotting of the basal portion of the stem.
• The bark turns brittle and often gets peeled off in flakes, leaving open cracks and crevices. The internal tissues are discoloured and disintegrated, emitting a bad smell.
• Bracket formation at the base of the trunk.  Ganoderma appears at the base of the trunk. Ultimately the palm dies off.

Root (wilt)

Disease symptoms

• The root (wilt) affected coconut are susceptible to diseases such as leaf rot and pests such as rhinoceros beetle and red palm weevil.
• Chance of confusing the pests and disease symptom with the root (wilt) disease

IPM for Coconut

To know the IPM practices for Coconut, click here.

Source: NIPHM and Directorate of Plant Protection, Quarantine & Storage

 

3.04   

 

204 ratings

Coconut: Insect, Mite and Nematode Pests

1. Rhinoceros beetle
2. Red palm weevil
3. Black headed caterpillar
4. Coconut eriophyid mite
5. Termite
6. Nematode
7. IPM for Coconut

Rhinoceros beetle

Biology:

• Egg: Females lays 140 - 150 oval creamy white eggs in manure pits or decaying vegetable matter at a depth of 5 to 15 cm. Egg periods is 8 to 18 days.
• Grub: Grub is stout, sluggish, white “C”-shaped with pale brown head and found at a depth of 5 to 30 cm.
• Pupa: Grub pupates in earthen cells at a depth of 0.3 to 1 m
• Adult: Adult beetle is stout, brownish black or black and has a long horn projecting dorsally from the head in male. Horn is short in female.

Damage symptoms:

• The adult beetle bores into the unopened fronds and spathes. Damage by the pest leads to 10 to 15% loss in yield
• The attacked frond when fully opened shows characteristic triangular cuts.
• Central spindle appears cut or toppled
• Fully opened fronds showing characteristic diamond shaped cuttings
• Holes with chewed fibre sticking out at the base of central spindle.

Natural enemies of rhinoceros beetle:

• Predator: Reduviid bug

Red palm weevil

Biology:

• Egg: Oval and creamy white in colour. Eggs laid in scooped out small cavities, wounds and other cut injuries on the trunk
• Grub: Light yellowish grub without legs. Stout, fleshy and apodous with a conical body bulged in middle and tapering towards the end
• Pupa: The full frown larva pupates inside the stem and fibrous cocoon made out of fibrous strands
• Adult: Reddish brown weevil has six dark spots on thorax. Male has conspicuous long snout has a tuft of hairs

Damage symptoms:

• Red palm weevil is one of the most destructive pests of coconut, oil palms and ornamental palms
• The hole can be seen on the stem with chewed up fibres protruding out.
• Many times reddish brown liquid can be seen oozing out from the hole.
• The grubs cause damage inside the stem or crown by feeding on soft tissues and often cause severe damage especially when a large number of them bore into the soft, growing parts. In case of severe infestation the inside portion of trunk is completely eaten and become full of rotting fibres.
• In case of young palms the top withers while in older palms the top portion of trunk bends and ultimately breaks at the bend (wilting).
• Sometimes the gnawing sound produced by the feeding grubs inside will also be audible.
• In the advanced stage of infestation yellowing of the inner whorl of leaves occur. The crowns falls down or dry up later when palm is dead.

Black headed caterpillar

Biology:

• Larva: Caterpillar is greenish brown with dark brown head and prothorax, and a reddish mesothorax. It has brown stripes on the body.
• Pupa: It pupates inside the web itself in a thin silken cocoon
• Adult: Greyish white in colour;
• Female: Females are with long antenna and three faint spots on the forewings
• Male: Males are with fringed hairs in hind wings in apical and anal margin.

Damage symptoms:

• The coconut trees of all ages are attacked.
• Dried up patches on leaflets of the lower leaves, only three or four youngest leaves at the center of the grown remain green.
• Galleries of silk and frass on underside of leaflets.
• In case of severe infestation the whole plantations present a scorched appearance.

Natural enemies of black headed caterpillars:

• Parasitiods: Bracon spp., Ichneumon spp., Goniozus nephantidis, Brachymeria spp. etc.
• Predators: Reduviid bug, spider, red ant, earwig, ground beetle etc.

Coconut eriophyid mite

Biology:

• Mites are usually found under the bracts of fertilized female flowers and do not infest the unfertilized flowers. This mite is very minute in size measuring 200 – 250 micron in length and 36 – 52 micron in width with two pairs of legs. Nymph and adult are pale in colour with elongate body and worm like appearance. The life cycle of this mite, which consists of egg, two larval instars and an adult stage, is completed in 7 -10 days.

Damage symptoms:

• The earliest symptom on 2-3 month old buttons is pale yellow triangular patches seen below the perianth.
• Later, these patches become brown. Severely affected buttons may fall. As the buttons grow, brown patches lead to black necrotic lesions with longitudinal fissures on the husk.
• Oozing of the gummy exudation from the affected surface of the nuts.
• Uneven growth results in distortion and stunting of nuts leading to reduction in copra yield. In severe cases, the nuts are malformed with cracks and hardened husk.

Natural enemies of coconut eriophyid mite:

• Predators: Phytoseiid mites, ladybug beetles, syrphid flies, minute pirate bug, Oligota spp., lacewing

Termite

Biology:

• Egg: Dull, kidney shaped and hatches in 30-90 days.
• Nymph: Moult 8-9 times and are full grown in 6-12 months.
• Adult: Creamy coloured tiny insects resembling ants with dark coloured head.

Damage symptoms:

• Termites are likely to cause damage to transplanted seedlings particularly in the earlier stage (wilting of seedlings).
• Base of trunks plastered with runways made of soil and fibres.

Biological control of termites through EPNs:

• EPNs seek out and kill all stages of harmful soil-dwelling insects. They can be used to control a broad range of soil-inhabiting insects and above-ground insects in their soil-inhabiting stage of life. The IJs emerge from cadaver, search for termites, infect, kill and again multiply and remain in the moist soil. Termites which are major pests in sugarcane can be managed by using EPNs effectively. EPN can be produced even at farmer level using either Galleria or Corcyra as a host.

Nematode

• Among nematodes, burrowing nematode (Radopholus similis) damages the roots of coconut. Burrowing nematode populations survive under field conditions for six months in moist soil (27 to 36°C) and one month in dry soil (29 to 39°C), whereas it survives for 15 months in moist soil (25.5 to 28.5°C) and 3 months in dry soil (27 to 31°C) under greenhouse conditions. The nematode survives in roots of stumps of felled coconut palms up to six months.

Damage symptoms:

• The nematode infested coconut palms exhibit general decline, yellowing, button shedding, and reduction in leaf size.
• The symptoms on roots are more specific.
• Elongated orange colour lesions are seen on tender and semi hard roots.
• Consequent to nematode parasitization and multiplication these lesions enlarge and coalesce to cause extensive rotting of roots.
• Tender roots on heavy infestation become spongy in texture.

IPM for Coconut

To know the IPM practices for Coconut, click here.

Source: NIPHM and Directorate of Plant Protection, Quarantine & Storage

 

3.02   

 

192 ratings

Coconut Pests

1. Pests of National Significance
1. Insect and mite pests
2. Diseases
3. Weeds
1. Broadleaf
2. Grasses
3. Sedges
4. Nematodes
5. Rodents
4. Pests of Regional Significance
1. Insect pests
2. Diseases
5. IPM for Coconut

Pests of National Significance

Insect and mite pests

• Rhinoceros beetle: Oryctes rhinoceros Guest (Coleoptera: Scarabaeidae)
• Red palm weevil: Rhynchophorus ferrugineus Olivier (Coleoptera: Curculionidae)
• Black headed caterpillar: Opisina arenosella Walker (Lepidoptera: Xylorictidae)
• Eriophyid mite: Aceria guerreronis Keifer (Acarina: Eriophyidae)
• Termite: Odontotermes sp (Isoptera: Termitidae)

Diseases

• Bud rot: Phytophthora palmivora Butler
• Stem bleeding: Thielaviopsis paradoxa De Seynes
• Leaf rot: Exserohilum rostratum & Colletotrichum gleosporioides Drechsler
• Cadang cadang disease: Coconut cadang-cadang viroid (CCCVd)

Weeds

Broadleaf

• Crofton weed: Eupatorium odoratum L. (Asteraceae)
• Sensitive plant: Mimosa pudica L. (Fabaceae)
• Siam weed: Chromolaena odorata L. R.M. king & H. Rob (Asteraceae)
• Carrot grass: Parthenium hysterophorus L. (Asteraceae)
• Coatbuttons: Tridax procumbens L. (Fabaceae)
• Pigweed: Amaranthus viridis Hook. F. (Amaranthaceae)
• Common purselane: Portulaca oleracea L. (Portualacaceae)
• Field bindweed: Convolvulus arvensis L. (Convolvulaceae)

Grasses

• Cogon grass: Imperata cylindrica (L.) Raeusch. (Poaceae)
• Goose grass: Eleusine indica (L.) Gaertner. (Poaceae)
• Burmuda grass: Cynodon dactylon (Poaceae)

Sedges

• Purple nutsedge: Cyperus rotundus L. (Cyperaceae)
• Flat sedge: Cyperus iria L. (Cyperaceae)

Nematodes

• Burrowing nematode: Radopholus similis

Rodents

• Palm civet: Vivera zibatha (Carnivora: Viverridae)
• Black rat: Rattus rattus Linnaeus (Rodentia: Muridae)
• Indian gerbil: Tatera indica Hardwicke (Rodentia: Muridae) (nursery/seedling)
• The lesser bandicoot or Indian mole-rat: Bandicota bengalensis Hardwicke (Rodentia: Muridae)

Pests of Regional Significance

Insect pests

• Cock chafer beetle: Leucopholis coneophora Burm (Coleoptera: Scarabaeidae)
• Coreid bug: Paradasynus rostratus (Hemiptera: Heteroptera)

Diseases

• Tanjavur wilt: Ganoderma lucidum Lingzhi or Reishi
• Root wilt: Phytoplasma sp
• Papery leaf blight: Pestalotia palmarum Cooke

IPM for Coconut

To know the IPM practices for Coconut, click here.

Source: NIPHM and Directorate of Plant Protection, Quarantine & Storage

 

3   

 

180 ratings

Coconut: Crop Stage-wise IPM

1. Nursery stage
2. Pre-planting stage
3. Growth stage
4. Mature palm

Management	Activity
Nursery stage
	Common cultural practices: • Select good mother palm for obtaing seedlings i.e. it must be of 20 years of age, yield more than 80 nuts/annum. • Provide proper shade, irrigation & drainage. • Rogue out diseased seedling. • Employ locally made rat traps. • Use resistant/tolerant varieties. • Sow the ecological engineering plants. • Removal and destruction of alternate host weeds.
Weed	• Hand weeding and timely mulching.
Nematodes	Cultural control: • Use of less susceptible, tolerant cultivars or hybrids of coconut and intercrops in infested areas. • Avoid use of banana as a shade crop in coconut nurseries. Biological control: • Application of cow dung, FYM, oil cakes and green manure to the basins. • Crotolaria juncea may be cultivated in the basin and interspaces and used as green manure. • Incorporate leaves and tender stem of Crotolaria juncea, Pueraria javanica and Glyricidia maculata into the soil in Sep-Oct.
Pre-planting stage
	Cultural control: • Prepare proper pits. • Timely planting should be done. • Maintain proper spacing. • Fill the pit with FYM, red earth and sand mixture.
Weeds	Cultural control: • Prepare beds of 1-1.5 m width and of convenient length with 75 cm space between beds. • In areas where drainage is poor, prepare raised beds (10-20 cm height) • Select good mother palm i.e. must be of 20 years of age, yield more than 80 nuts/annum, etc
Soil borne pathogens, wilt, nematodes and resting stages of insect pests	Cultural control: • Deep ploughing of fields during summer. • Early sowing of the crop prevents it from nematode infestation • Liming the soil to pH 6.0-7.0, as well as reducing nitrogen levels in the soil, significantly reduces wilt.
Growth stage
	Common cultural practices: • Provide timely irrigation, organic manure, fertilizer as per the recommended dose, drainage, weeding, mulching, inter culture etc. Common mechanical practices: • Set up light traps following the first rains in summer and monsoon period to attract and kill the adult beetles. • Cut and burn disease affected portions of palms, buttons, wilted palms and dead palms. Common biological practices: • Conserve natural enemies through ecological engineering • Augmentative release of natural enemies
Nutrients	• For coconut mite affected plants with 50 Kg FYM, 0.52 Kg N /acre, 2 Kg SSP/ 3.5 Kg MOP, 1 Kg gypsum & 50 g of Borax
Rhinoceros beetle and cock chafer beetle**	Cultural control: • Collect and destroy the various life stages of the beetle from the manure pits (breeding ground of the pest) whenever manure is lifted from the pits. Mechanical control: • During peak period of population build up, the adult beetle may be extracted from the palm crown using GI hooks. • Install aggregation pheromone traps away from the main plantation. • Set up pheromone trap for rhinoceros beetle @ 1 trap/100 ha by fixing it to the plant at 0.6 to 1 m height to trap and kill the beetles. Biological control: • Release of Baculovirus oryctes inoculated adult rhinoceros beetle @ 6 beetles/acre reduces the leaf and crown damage caused by this beetle. • Soak castor cake at 1 Kg in 5 l of water in small mud pots and keep them in the coconut gardens to attract and kill the adults. • Apply mixture of either neem seed powder + sand (1: 2) @ 150 g/palm or neem seed kernel powder + sand (1: 2) @ 150 g/palm in the base of the 3 inner most leaves in the crown.
Bud rot	Cultural control: • Adopt proper spacing and avoid over-crowding in bud rot prone gardens. Chemical control: • Spray copper oxy chloride 50% WP @ 1 Kg in 300-400 l of water/acre on the crown of the neighboring palms as a prophylactic measure before the onset of monsoon.
Leaf rot	• Follow common cultural, mechanical and biological practices Mechanical control: • Remove the rotten portions from the spear and the two adjacent leaves.
Mature palm
Rhinoceros beetle	• Same as in growth stage
Coconut eriophyid mite	Cultural control: • Grow intercrop (sun hemp, four crops/year) and shelter belt with Casuarina all around the coconut garden to check further entry. • Apply urea 1.3 Kg, super phosphate 2.0 Kg and muriate of potash 3.5 Kg/palm/year. • Increased quantity is recommended to increase the plant resistance to the mite. • Soil application of micro nutrients such as borax 50 g + gypsum 1.0 Kg + manganese sulphate 0.5 Kg/palm Chemical control: • Fenpyroximate 5%EC @ 10 ml/l (spray fluid volume as required)
Red palm weevil	Cultural control: • Avoid the cutting of green leaves. If needed, they should be cut about 120 cm away from the stem in order to prevent successful inward movement of the grubs through the cut end. Mechanical control: • Set up pheromone trap for red palm weevil @ 1 trap/100 ha by fixing it to the plant at 0.6 to 1 m height to trap and kill the beetles. • Coconut log traps: Setting up of attractant traps (mud pots) containing sugarcane molasses 2½ Kg or toddy 2½ l (or pineapple or sugarcane activated with yeast or molasses) + acetic acid 5 ml + yeast 5 g + longitudinally split tender coconut stem/ logs of green petiole of leaves of 30 numbers in one acre to trap adult red palm weevils in large numbers.
Leaf eating caterpillar / black headed caterpillar	• Follow common cultural, mechanical and biological practices. Cultural control: • As a prophylactic measure, the first affected leaves may be cut and burnt during the beginning of the summer season. Chemical control • Cut sharply at an angle and insert the root in the insecticidal solution containing monocrotophos 36% WSC @ 10 ml + water 10 ml in a 7 x 10 cm polythene bag.
Coreid bug**	• Follow common cultural, mechanical and biological practices. Mechanical control: • Set up light traps to trap and collect adult bug.
Termites	• Follow common cultural, mechanical and biological practices. Cultural control: • Copious irrigation and drenching nurseries or basin of transplanted seedlings. Mechanical control: • Digging the termitaria and destruction of the queen is the most important in termite management. Biological control: • Spray neem oil 5% (50 ml/l) once on the base and up to 2 m height of the trunk for effective control. • Entomopathogenic nematodes (EPNs) can be sprayed at the rate of 100 millionnematodes per acre, in termite infested fields OR • EPN infected cadavers of Galleria/Corcyra larvae containing live infective juveniles (IJs)are implanted in soil at plant bases at the rate of four cadavers per plant during May/ June and/or September for termite control.
Bud rot	• Follow common cultural, mechanical and biological practices. • Same as in growth stage
Leaf rot	• Follow common cultural, mechanical and biological practices. • Same as in growth stage
Stem bleeding	Follow common cultural, mechanical and biological practices. Cultural control: • Along with 50 Kg organic manure, apply 5 Kg neem cake containing the antagonistic fungi, Trichoderma culture to the basin during September. • Provide adequate irrigation during summer and drainage during rainy season along with recommended fertilizer. Mechanical control: • Destroy the chiselled materials by burning. • Avoid any mechanical injury to trunk. Biological control: • Apply neem cake at the rate of 5 Kg/palm in the basin along with other organics.
Note: The pesticides dosages and spray fluid volumes are based on high volume sprayer. ** Pest of regional significance.

Source: NIPHM and Directorate of Plant Protection, Quarantine & Storage

 

3.03   

 

164 ratings

Coconut: Natural Enemies

1. Natural Enemies of Coconut Insect Pests
1. Parasitoids
2. Predators
2. Resistant/tolerant varieties
3. IPM for Coconut

Natural Enemies of Coconut Insect Pests

Parasitoids

Predators

Resistant/tolerant varieties

Pest/disease	Tolerant/resistant variety*
Resistance to root (wilt) disease	Kalpa Raksha
Root (wilt) disease	Kalpa Sree
Root (wilt) disease	Kalpa Sankara (CGD x WCT)
Eriophyid mite	Kalpa Haritha

IPM for Coconut

To know the IPM practices for Coconut, click here.

Source: NIPHM and Directorate of Plant Protection, Quarantine & Storage

 

3   

 

165 ratings

Nutritional Deficiencies/Disorders of Coconut

1. Nitrogen
2. Phosphorus
3. Boron
4. Manganese
5. Magnesium
6. Sulphur
7. Iron
8. Zinc
9. Calcium
10. Copper
11. IPM for Coconut

Nitrogen

Nitrogen deficiency is typically caused by insufficient nitrogen in the soil. Nitrogen deficiency begins as a uniform light green discoloration / yellowing (uniform chlorosis) of the oldest leaves. Yellowing starts from tip to base of the lower leaves and will proceed up. As the deficiency progresses, younger leaves will also become discoloured. Older leaves are golden yellow colour. Growth virtually stops when N deficiency is severe and become shedding of leaves.

Correction measure: Foliar application of 2% urea thrice at fortnightly interval or soil application of 1-2 Kg urea / tree or root feeding of 1% urea 200 ml twice a year.

Phosphorus

Deficiency occurs in acid and alkaline soils. Purple coloration in leaves (in severe cases may leaves turn yellow before drying prematurely). Sluggish growth. Leaves stay upright. Premature leaf shedding. The growth, leaf size and leaf number reduced. The root growth is restricted if phosphorus deficiency is recorded.

Correction measure: Foliar spray of DAP 2% twice at fortnightly interval or soil application of FYM 5 Kg/tree. Root feeding of 1% DAP 2 ml twice a year.

Boron

Boron deficiency is caused by insufficient boron in the soil. It may be caused by soil drying and high soil pH, while temporary boron deficiency is caused by heavy leaching. Symptoms always occur on newly emerging leaves, and remain visible on these leaves as they mature and are replaced by younger leaves. One of the earliest symptoms of boron deficiency on coconut palm is leaf wrinkling and manifested as sharply bent leaflet tips, commonly called “hook leaf”. These sharp leaflet hooks are quite rigid and cannot be traightened out without tearing the leaflets. Leaves have a serrated zigzag appearance. One of the most common symptoms of boron deficiency is the failure of newly emerging spear leaves to open normally. In a chronic stage, multiple unopened spear leaves may be visible at the apex of the canopy. Boron deficiency also occurs in inflorescence and nuts. The inflorescence and nuts are become necrotic.

Correction measure: Application of borax/sodium tetraborate 0.2% (2 g/l of water), (75-100 ml/seedling), borax/ sodium tetraborate/octaborate 15-20 g/plan.

Manganese

The newest leaves of manganese deficient palms emerge chlorotic with longitudinal necrotic streaks. As the deficiency progresses, newly emerging leaflets appear necrotic and withered on all but basal portions of the leaflets. This withering results in a curling of the leaflets about the rachis giving the leaf a frizzled

appearance (‘frizzle top’). On new leaves of manganese-deficient palm, necrotic leaflet tips fall off and the leaf has a signed appearance. In severely manganese deficient palms, growth stops and newly emerging leaves consist solely of necrotic petiole stubs.

Correction measure: Soil application of MnSO₄ @ 10 Kg/acre

Magnesium

Magnesium deficiency appears on the oldest leaves of palms as broad chlorotic (yellow) bands along the margins with the central portion of the leaves remaining distinctly green. In severe cases leaflet tips may become necrotic. Older leaves become bronzed and dry appearance. Leaflets show necrosis and turn to reddish brown with translucent spots yellowing starts at the tip and spreads to the base.

Correction measure: Soil application of MgSO₄ 1-2 Kg/tree/year. Root feeding of 200 ml of 0.2% MgSO₄ twice a year

Sulphur

Typical symptoms are yellowish-green or yellowish-orange leaflets. Older leaves are remaining green. Leaves droop as the stem becomes weak. In older palms, leaf number and size are reduced. Sometimes an apron of dead fronds develops around the stem due to weakness of the rachis. Nuts may fall prematurely. Copra is rubbery and of poor market quality.

Correction measure: Soil application of gypsum 2 - 5 kg/tree/year. Root feeding of 0.2% gypsum

Iron

Iron deficiency usually appears on palms growing in poorly aerated soils or those that have been planted too deeply. Water logged soils and deep planting effectively suffocate the roots and reduce their effectiveness in taking up nutrients such as iron. The main symptom of iron deficiency is chlorosis or yellowing between the veins of new leaves (uniform chlorotic new leaves as the deficiency progresses, the tips become necrotic and leaf size reduced).

Correction measure: Application of FeSO₄ 0.25 to 0.5 Kg/tree/year

Zinc

Zinc deficiency is characterized by formation of small leaves wherein the leaf size is reduced to 50%. Leaflets become chlorotic, narrow and reduced in length. In acute deficiency, flowering is delayed. Zinc deficiency will also lead to button shedding. Its occurs mostly in saline soils.

Correction measure: Soil application of ZnSO₄ @ 10 Kg/acre

Calcium

Young leaves exhibit narrow white bands at margins. Interveinal chlorosis. Rusty appearance in leaf margin. Rolling up of leaves. Occurs only in acid soil.

Correction measure: Soil application of lime based on lime requirement and root feeding of 1% calcium nitrate.

Copper

Coppery bluish leaf. Rolling of terminal leaves due to loss of turgor. Leaves appear to be bleached grey. Fail to produce flowers.

Correction measure: Soil application of CuSO₄ @ 10 Kg/acre.

IPM for Coconut

To know the IPM practices for Coconut, click here.

Source: NIPHM and Directorate of Plant Protection, Quarantine & Storage

 

3   

 

175 ratings