Pest Management of Coconut

Pests of Coconut

1.Rhinoceros beetle: Oryctes rhinoceros-

Pest population occurs round the year but population maximum during June – Sep coinciding with the onset of monsoon.

Symptoms of Damage:

• 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 fiber sticking out at the base of central spindle.

Identification of the Pest:

• Egg: Oval creamy white egg in manure pits or decaying vegetable matter at a depth of 5 to 15 cm. Egg periods is 8 to 18 days. Female laid 140 to 150 eggs.
• 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 a male. Horn is short in a female.

Management:

Cultural Method:

• Remove and burn all dead coconut trees in the garden (which are likely to serve as the breeding ground) to maintain good sanitation.
• Collect and destroy the various bio-stages of the beetle from the manure pits ( the breeding ground of the pest) whenever manure is lifted from the pits.

Mechanical Method:

• During the peak period of population build up, the adult beetle may be extracted from the palm crown using GI hooks.
• Set up light traps following the first rains in summer and monsoon period to attract and kill the adult beetles.

Chemical Method:

• The topmost three leaf axils around the spindle may be filled with any of the following mixtures as a prophylactic measure:

(a) Sevidol 8G 25 g + fine sand 200 g, which is to be done thrice in a year in April-May, September-October and December-January.
(b) For seedlings, apply Naphthalene balls 10.5 g (approx. three to four balls) covered with fine sand, once in 45 days.

• Place phorate 10 G 5 g in perforated sachets in two inner most leaf axils for two times at six months intervals.
• Treat manure pits and other possible breeding sites with 0.01% carbaryl (50 % WP) on w/w basis. Treatment will have to be repeated every six months.

 Trap Method:

• Set up Rhino lure pheromone trap @ five traps/ha to trap and kill the beetles. The dispenser may be hanged in a plastic bucket having 2 liters of insecticide solution once in a week. Trapped beetles can be disposed of.

Biological Method:

• Application of green muscardine fungus, Metarrhizium anisopliae @ 5 x 10¹¹ spores / m³ – spray 250ml Metarrizhium culture + 750ml water in manure pits to check the perpetuation of the pest.
• Field release of Baculovirus oryctes inoculated adult rhinoceros beetle @ 15 beetles/ha reduces the leaf and crown damage caused by this beetle.
• Soak castor cake at 1 kg in 5 liters of water in small mud pots and keep them in the coconut gardens to attract and kill the adults.
• Apply the mixture of either neem seed powder + sand (1:2) @150 g per palm or neem seed kernel powder + sand (1:2) @150 g per palm in the base of the three inner most leaves in the crown.

2.Coconut Eriophyid: Aceria guerreronis

Pest population occurs round the year but population maximum during June – Sep coinciding with the onset of monsoon.

Symptoms of Damage:

• 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 the reduction in copra yield. In severe cases, the nuts are malformed with cracks and hardened husk.

Identification of the Pest:

• 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 color with the 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.

Management:

Cultural Method:

• Collect and destroy all the fallen buttons of the affected palm.
• Grow intercrop (sun hemp, four crops/year) and shelter belt with casuarina all round the coconut garden to check further entry.
• Providing adequate irrigation.
• Apply urea 1.3 kg, Super phosphate 2.0kg and muriatic of potash @ 3.5 kg/palm/year. Increased quantity is recommended to increase the plant resistance to the mite.
• Soil application of micro nutrients like, Borax 50 g + gypsum 1.0kg + Manganese sulphate 0.5 kg/palm/ year TNAU Micronutrient solution 200 ml/tree.

Chemical Method:

Spot application of ecofriendly Botanicals

• Round 1: Azadirachtin 1% (5 ml in one lit. of water)
• Round 2: Neem oil + Teepol (30 ml in one lit. of water)
• Triazophos 40 EC 5 ml/lit or monocrotophos 36 WSC @ 2 ml / lit or carbosulfan 25 EC 2 ml/ lit in alternation with neem azal 1% 5ml/lit as spot application
• Neem cake application @ 5 kg per palm per year

Preparation of neem oil + garlic emulsion (2%):

• To prepare 10 liters of 2% neem oil + garlic emulsion, 200 ml neem oil, 200 g garlic and 50 g ordinary bar soap are required. Slice the bar soap and dissolve in 500 ml lukewarm water. Grind 200 g of garlic and take the extract in 300 ml of water. Pour the 500 ml soap solution in 200 ml neem oil slowly and stir vigorously to get a good emulsion. Mix the garlic extract in the neem oil + soap emulsion. Dilute this 1-litre stock solution by adding 9 liters of water to get 10 liters of 2 % neem oil + garlic emulsion.

Method of Application

• The botanicals should be applied in the sequence indicated above at 45 days interval using a one-litre hand sprayer. Rocker or Pedal sprayer can be used for spraying small trees.
• The spray should be applied at the crown region by a climber covering only the top six bunches during a nonrainy season.

Precautions and Safety Measures

• Spraying should be avoided during the windy season to prevent contamination.
• At the time of spraying, protective mask and clothing should be used.
• Wash face and hands cleanly with soap after spraying.

Biological Method:

• Entomofungal pathogen Hirsutella thompsonii and Verticillium lecanii are reported to be promising in managing the mites.
• Both the pathogens are mass multiplied by a commercial firm and sold in the market.

3. Leaf Eating Caterpillar/ Black Headed Caterpillar: Opisina arenosella

This causes severe damage to palms in coastal and backwater areas and certain internal packets of peninsular in India. The pest occurs round the year with the spike in population during summer (Mar-May).

Symptoms of Damage:

• 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 an underside of leaflets.
• In the case of severe infestation, the whole plantations present a scorched appearance.

Identification of the Pest:

• 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 Moth: Greyish white in color
  • Female: with long antenna and three faint spots on the forewings
  • Male: with fringed hairs in hind wings in the apical and anal margin.

Management:

Cultural Method:

• As a prophylactic measure, the first affected leaves may be cut and burnt during the beginning of the summer season.

Chemical Method:

• When infestation is very severe in young palms and if the biocontrol is not likely to be effective, spray the undersurface of the fronds with dichlorvos 0.02% (Dichlorovos 100EC), Malathion 50 EC 0.05% (1 ml/lit), quinalphos 0.05%, phosalone 0.05%.

Biological Method:

• Among the larval parasitoids, the Bethylid, Goniozus nephantidis, (Elasmus nephantidis (brown species) and Brachymeria nosatoi ) is the most effective in controlling the pest. The optimum level of release is 1:8 of host-parasitoid ratio. The parasitoid should be released @ 3000/ha under the coconut trees when the pest is in the 2nd or 3rd instar larval stage. Parasitoid release trap may be used to release the parasitoid at the site of feeding. Parasitoids should not be released in the crown region since they will be killed by predators like spiders and reduviid bugs. This should be released only three weeks after chemical spray.
• Release the larval (Bethylid, Braconid and Ichneumonid) and pupal (Eulophid) on (chalcid) parasitoids and predators periodically from January, to check the build up of the pest during summer.

4. Slug Caterpillar: Parasa lepida and Contheyla rotunda

Symptoms of Damage:

• The larvae are the destructive stage if the pest. The young larvae feed on the lower epidermis of the leaf. As they mature, the whole leaf blade is eaten leaving the midribs. In a heavy infestation, the larvae may defoliate the palm.

Identification of the Pest:

• Egg: Flat shiny eggs on the under surface of leaves
• Larva: the Greenish body with white lines and four rows of spiny scoli tipped red or black, which cause irritation and pain.
• Pupa: It pupates in a compact elliptical chocolate brown shell-like cocoon, which is convex above and flat ventrally as stems. Cocoons are covered with irritating spines and hairs
• Adult: Adult moth has green wings with a prominent dark patch at the base of each forewing.

Management

Chemical Method:

• Collect and destroy the immature stages of the insects by conducting a study (or neem campaign) wherever possible and spray carbaryl 50 WP 2 gm/lit.
• Spray carbaryl 50 WP 2 g/l.
• Spray dichlorvos 76 WSC 2 ml/lit.

Mechanical Method:

• Set up light traps to trap and collect adult moths. About five light traps may be installed per hectare.

5.Coconut Skipper: Gangara Thyrsis; Suastus gremius

Pest population occurs round the year but population maximum during June – Sep coinciding with the onset of monsoon.

Symptoms of Damage:

• One-half of the leaflets are cut and rolled into a case
• The rolled leaflets are dried.

Management:

Chemical Method:

• Collect and destroy the immature stages of the insects by conducting a study (or neem campaign) wherever possible and spray carbaryl 50 WP 2 gm/lit.
• Spray dichlorvos 76 WSC 2 ml/lit.

6.Coreid Bug: Paradasynus rostratus

It occurs in coastal areas and high ranges in Kerala (Trivandrum, Wynad, Kasaragod).

Symptoms of Damage:

• The adults and nymphs feed by desapping the contents on the button and developing nuts below the perianth region.
• The attacked buttons become deformed with characteristic crevices on the husk below the perianth with gum exudations, and the tender nuts become barren.
• Severe damage leads to nut fall and malformation of mature nuts.

Identification of the Pest:

• The adults are brown colored measuring 2 cm in size. The life cycle is completed in a month’s time.

Management:

Chemical Method:

• Collect and destroy the immature stages of the insects by conducting a study (or neem campaign) wherever possible and spray carbaryl 50 WP 2 gm/lit.
• Apply 0.1% carbaryl suspension on the newly opened inflorescence after the receptive phase of the female flowers and spray the entire crown excluding the leaves and older bunches (at 45 days interval). Destruction of pollinating insects can be avoided if spraying is done in afternoon hours.
• Spray dichlorvos 76 WSC 2 ml/lit.

Mechanical Method:

• Set up light traps to trap and collect adult moths.

7.Bag Worm: Manatha albipes

Symptoms of Damage:

• Small and irregular hole on the leaves. Silken spin stick strand bags below the leaf.

Identification of the Pest:

• Larva: Inside the conical bags constructed with silk and thread

Management:

Chemical Method:

• Collect and destroy the immature stages of the wherever possible and spray carbaryl 50 WP 2 gm/lit.
• Spray dichlorvas 76 WSC 2 ml / lit.

Mechanical Method:

• Set up light traps to trap and collect adult moths.

8.White Grub/ Cockchafer Beetle: Leucopholis coneophora

These cream-colored grubs are found in abundance in sandy loam tracts of Kerala and Karnataka, especially in Sep – Oct and the beetles emerge in May-June.

Symptoms of Damage:

• In nursery the grubs feet the tender roots and tunnel into the bole of the collar region resulting in drying and yellowing
• In older plantations infestations results in yellowing of leaves, premature nut shedding, delayed flowering, retardation in growth and yield decline.
• White grubs are exposed when base of tree dug
• Tuber crops grown as intercrops are also affected.

Identification of the Pest:

• Egg: Oval in shape and creamy white in color when freshly laid. Before hatching, they turn to dirty white.
• Grub: Curved, fleshy and wrinkled. They are creamy white in color with brown head.
• Adult: Brown colored beetle with striated wings not covering the abdomen fully

Management:

Cultural Method:

• Repeated ploughing once a week for 4 to 5 times after first rains in summer reduce the pest population by exposing the pest to predation by birds and other animals.
• Plant neem twigs with leaves in coconut gardens after rain to attract and kill adult beetles
• Plough or dig the infested soil synchronizing with pre-monsoon showers.

Mechanical Method:

• Set up light trap @ 1 / ha or bonfire

Chemical Method:

• Soil application – Malathion 5 D 25 kg/ ha at the time of planting (Treat the soil with phorate 10G @ 100 g/palm or drench with chlorpyrifos 0.04% suspension. The treatment should be given twice, first during April-May after the receipt of pre-monsoon showers and second during the month of September – Recommended by KAU).

Physical Method:

• Collect and destroy the adult beetles attracted to trees like neem, Ailanthus, and Acasia on the receipt of monsoon showers (in the evening).

9.Termite: Odontotermes obesus

Pest population occurs round the year but population maximum during June – Sep coinciding with the onset of monsoon.

Symptoms of Damage:

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

Identification of the Pest:

• Adults: Cream colored, tiny insects resembling ants with dark colored head

Management:

Cultural Method:

• Locate termite mounds in or near the coconut nursery or garden and destroy.
• Adoption of field sanitation by the disposal of organic matter in nursery soil and covering germinating nuts with a layer of river sand.

Chemical Method:

• Spray Copper Sulphate 1% or Cashew Nut Shell Oil 80% or spray Chlorpyriphos @ 3ml/lit of water, Neem Oil 5% or NSKE 20% to preserve plaited coconut leaves from the termite attack.
• Apply calcium at the base of the trunk for control of termite attack.
• Swabbing with Neem oil 5% once on the base and up to 2 m height of the trunk for effective control.

10. Lacewing BugTermite: Stephanitis typicuTermites

Symptoms of Damage:

• White spots on the upper surface of the leaves
• Lace bug sucks sap from coconut foliage; it acts as a vector in transmission of Phytoplasma from the root (wilt) affected palms to healthy palm.

Identification of the Pest:

• Nymph: White with dark patches.
• Adults: White colored adults with netted venation on the wing.

Management:

Cultural Method:

• Remove leaflets harboring these insects and destroy them.

Chemical Method:

• Spray any one of the following;
  • Malathion 50 EC @ 2 ml/lit
  • Dimethoate 30 EC @1 ml/lit
  • Methyl demeton 25 EC @1 ml/lit
  • Phosphamidon 40 SL @1.25 ml/lit
  • Methomyl 25 EC @2 ml/lit
  • 3% Neem oil

11.Scale Insect: Aspidiotus destructor

Symptoms of Damage:

• It occurs more in summer. Scale insects affect on leaves and nuts of coconut palms.
• A severe infestation, scale forms a continuous crust over flower spikes, young nuts and the lower surface of leaves.
• On leaves, A. destructor causes scales with yellow spots developing where the crawlers have settled and grown into adults.
• Nymphs reside and develop in leaf by sucking the sap.
• Entire leaves may turn yellow to brown and fall. Sooty mould may develop. The bright yellow color of affected coconut palms is clearly visible from a great distance.
• In extreme cases, the leaves dry out, entire fronds drop off, and the crown dies. Heavy infestation results in stunting of new leaves, reduction of crop yield or complete crop failure.
• Infested coconut fronds exhibit yellow areas on the upper surface, formed by numerous yellow spots each marking the position of the coconut scale on the under the surface.

Identification of the Pest:

• Egg: hatching the young scales on the undersides of the leaves.
• Nymph: Covered with circular waxy secretion
• Adult: The scale is bright yellow and round or reddish (female) and oval (male) covered with semitransparent grayish white flat scale. Females are always wingless and remain under their scale their entire life. Adult males have one pair of membranous wings, move about actively in search of females and do not feed during the adult stage.

Management:

Chemical Method:

• Spray Fish Oil Rosin Soap (FORS) 2.5% or spray Malathion. A second round is given after 20 days.

Biological Method:

• The release of predatory Coccinellids, Chilocorus nigritius is found to be effective.

12.Mealy Bug: Pseudococcus longispinus

Symptoms of Damage:

• Mealy bugs colonize on all tender plant parts like bases of spear leaf, spadix and inflorescence and beneath the perianth of the nut.
• Mealy bugs infest the unopened heartleaf and inflorescence. It feeds plant sap. Leaves are yellowing and dry up.
• As a result, the leaves become highly stunted, suppressed, deformed and present a crinkled appearance.
• It is often confused with the leaf rot symptoms.
• The affected inflorescences are malformed and do not open. Even if they open, they do not bear nuts.
• Button mealy bugs colonize under the perianth lobes of tender nuts. Infested nuts harboring gravid mealy bugs remain on the spadix, which serves as inoculum for further spread.

Identification of the Pest:

• Nymph: Nymphs are flat, oval and yellow. Older nymphs of some species are covered with fluffy, white wax.
• Adult: The males are yellowish in color whereas the females are longer and narrow and white in color.

Management:

Cultural Method:

• Remove leaflets harbouring these insects and destroy them.

Chemical Method:

• Spray any one of the following;
  • Malathion 50 EC @ 2 ml/lt
  • Dimethoate 30 EC @1 ml/lt
  • Methyl demeton 25 EC @1 ml/lt
  • Phosphamidon 40 SL @1.25 ml/lt
  • Methomyl 25 EC @2 ml/lit
  • 3% Neem oil

 

Source-Tamil Nadu Agriculture University.