Coconut

Insect Management

Pests of Copra

• Insects cause serious damage to copra in storage.
• Apart from loss in tonnage, insect attack adversely affects the quality.
• In severe cases, the financial loss on this account may even exceed that arising from loss by weight.
• Following are the pests of copra.

(a) Carpophilus dimidiatus

• It is the most common insect in copra godowns.
• In India also it is commonly present in copra stores.
• The beetle is small, flat, broad, and about 3 mm in length and 1.5 mm in width.
• It can be readily distinguished from the other beetles by its shorter wing covers, which do not completely cover the abdomen.
• The beetle completes its life cycle in about five weeks.

(b) Necrobia rufipes

• Necrobia beetle has a world-wide distribution and is known as' Ham Beetle' in America and' Copra Bug' in the Pacific.
• It is generally metallic blue in colour but sometimes with a greenish lustre.
• Its length varies from 3.5 mm to 5.5 mm. The first five joints of the antennae are brown, the rest black, and the terminal three are expanded.
• It completes its life cycle in about 40 days.

(c) Ahasverus advena

• It is known as " Foreign Grain beetle,"and is present throughout the world.
• It has been recorded feeding upon a variety of stored products.
• It is abundant in copra stores, but is practically mycetophagous.
• The adult beetle is very small, measuring about 2 mm in length and 0.75 mm in width, and is chestnut brown in colour.
• The life cycle of the beetle is completed in about thirty days.

(d) Oryzaephilus surinamensis

• This Cucujid beetle is commonly known as " Saw Toothed Grain beetle," and it is a serious pest of stored grains; copra and other stored food products throughout the world.
• The adult beetle is small, flat, elongate, dark brown, about 3 mm in length and 0.75 mm in width.
• The pro-thorax has three longitudinal ridges with two depressed areas and its lateral margins are each armed with six prominent tooth-like projections.
• The beetle breeds throughout the year in the moulds and crevices of degenerated copra, and completes its life cycle in about thirty days.

(e) Tribolium castaneum

• It is commonly known as " Red Flour beetle ", and is primarily a pest of cereal products like wheat flour, ' suji ' and' maida " but causes damage to quite a number of other stored products including copra.
• The beetle is small, flat, elongated, reddish brown, about 3.5 mm in length and 1.25 mm in width.
• The first seven joints of the antennae show a gradual increase in size and the last three are thickened into a club.
• In India, its life cycle varies from six to twelve weeks.

(f) Trogoderma granaria

• This pest is known as' Khapra ' in the towns and villages of India, and its principal food is wheat.
• The adults are harmless, and only the grubs are destructive. The beetle is about 3.5 mm in length and 1 mm in width, and has a characteristic oval shape.
• The head is disproportionately small and is concealed from above by the pronotum.
• The life cycle in humid places is completed in about two months.

(g) Corcyra cephalonica

• This pest is commonly known as the Rice Moth and is a serious pest of stored paddy, rice, cereals, copra and other stored food products.
• The head and thorax of the moth are brownish in colour.
• The fore-wings are brown with a pinkish tinge, speckled with darker scales running longitudinally.
• The hind wings are shiny and silver grey.
• The wing expanse is about 25 mm.

(h) Ephestia cautella

• This is frequently referred to as the' Almond' or the' Fig Moth' and is one of the most important insects infesting dried fruits, cocoa, spices, cashew nut, copra and groundnut.
• The moth is about 6 mm in length with a wing expanse of 15 mm.
• Its colour varies with food and environments, but mostly the fore- wings are greyish-brown, some what mottled with a distinctly darker coloured transverse band.
• The average life cycle on mouldy copra is six weeks.

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Black-Headed Caterpillar

Scientific name:Opisina arenosella

Family: Oecophoridae

Order: Lepidoptera

Introduction

Larva

A major pest of coconut in India, earlier confined to coastal areas, but of late is seen occurring in interior plains of Andhra Pradesh, Karnataka and Tamil Nadu. Peak activity is observed in hot months (April- June).

• Attacks all palms except arecanut.
• Moth is medium sized with straw to ash grey body and uniform pale-whitish forewings.
• Creamy white, scale- like eggs are laid generally on older leaf-lets, or near larval galleries (if present) of the previous brood.
• Caterpillar is slender, elongated, pale greyish-green with reddish brown wavy longitudinal stripes and black head.
• Pupation is in cocoon constructed in larvae gallery.
• Life cycle is completed in about 2 months.

Symptoms of damage

Infected Leaf Lets

Larva scrapes and feeds on the surface tissues of the lower surface of the leaflet . It binds two halves of leaflets together, constructs a gallery of silk and frass and lives under it.

Affected Palm

Attacked leaflets turn brown and dry up. Attacks only lower leaves and from a distance these appear as if burnt. Bearing capacity of the tree and fruit size is reduced. Palmyra is the major source of infestation.

Control

Goniozus parasitoid laying eggs

A number of egg, larval and pupal parasitoids are being multiplied in four parasitoid breeding stations in Andhra Pradesh at Rajole, Ambajipet, Sompet and Narsapur.

Parasitoid pupae emerging from larvae of host

These parasitoids can be released first immediately after noticing the infestation, and subsequently three times at fortnightly intervals

• In young plants, clipping and burning of infested leaflets by early detection can be practised.
• For tall plants and large orchards a combination of biological and chemical methods are suggested.

Chemical

Root administration technique

Root administration of monocrotophos is most practical and widely adopted method. A dark brown active, pencil- thick root is taken out, and its end cut slantly, immersed into a container (polythene bag) with 10 ml monocrotophos and 10 ml water. The insecticidal , suspension is taken up by the tree in 24 hours. If the chemical does not get absorbed, the procedure should be repeated with another fresh root.

• If the tree is taller than 15 feet, the quantity of chemical should be increased proportionately.
• Before taking up the root administration matured fruits should be harvested and the next harvest should not be done till 45 days after insecticidal administration.

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Rhinoceros Beetle

Scientific name: Oryctes rhinoceros

Family: Scarabeidae

Order : Coleoptera

Introduction

• An important pest of coconut, found throughout India.
• Peak activity is noticed from July-September. Attacks all palms.

Marks of identification

• Adult beetle is stout, black or reddish-brown, elytra smooth and shiny, lower side of body brownish and hairy.
• A cephalic pointed horn is a characteristic feature, hence called as Rhinoceros beetle.
• Grub is stout, fleshy with an arched body, brownish head, three pairs of thoracic legs, ash grey wrinkled body except the posterior "tail" which is smooth and brownish.

Life cycle

• Eggs are laid in decaying organic matter such as dead tree trunks or compost heaps or pits.
• Larva feeds on decaying matter, usually 5-30 cm deep.
• Larvae become fully grown in 75-190 days.

Symptoms of damage

• Beetle bores into central shoots, spathes and petioles, chews the tissues, ingests the juice and throwsout dry fibrous part.
• Attacked central shoot topples down and the tree may be killed if the growing primordium is destroyed.
• Leaves of partly damaged crowns when grow show characteristic 'V' shaped cuttings on the leaflet.
• Similar damage is seen in oil palm , ornamental palm and others

Control

• Treat the manure pits with carbaryl dust, four times a year in January, April, July and October.
• Hook out beetles from crowns during July-September and fill the holes with lindane dust and sand ( 1: 1) mixture.
• Poison bait made out of rotting mustard, castor cake, toddy or dung and lindane attracts the beetles.

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Scales

Scientific name : Aspidiotus destructor

Family: Diaspididae

order : Homoptera

Introduction

• Scale insect occurs as a serious pest in some regions , on the west coast, especially during hot months.

Symptoms of damage

• Female lays eggs under its shield like scale.
• Crawlers move out to healthy leaflets, cluster in large numbers on the underside of leaflets feeding on cell sap.
• Leaflets turn yellowish and in severe cases wither and dry.
• In severe infestation scales may also congregate on green nuts and suck sap reducing the quality.
• Another hard scale, Chrysomphallus aonidum, and a coccid, Hemiberlesia lataniae have been reported as minor pests of oil palm, which result in yellowing of unfolded leaves and stunted growth.

Control

• Normally their population is kept under check by the natural enemies.
• Root feeding of monocrotophos suggested for black-headed caterpillar also controls scales.

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Termites

Scientific Name: Odontotermes sp.

Family: Termitidae

Order: Isoptera

Introduction

• Polyphagous, common in sandy, sandy loam's and laterite soils.
• Termites are social insects, live in mud nests or termitaria, have distinct castes, workers, kings and queen.
• Queen lives for several years and lays several thousand eggs every day.

Symptoms of damage

Affected coconut palm

These cause serious damage to seedlings in nurseries and transplanted seedlings particularly in the earlier stages. They gnaw into the husk and the tender roots, and more serious loss is caused when they nibble at the tender growing point.

Mud galleries on trunk

It is difficult to detect the trouble until the seedlings show signs of withering, when it will be too late to save them. Termites damage both coconut and oil palm in nursery and the transplanted seedlings.

• Wilting of the central shoot, stunted growth and presence of mud galleries are typical symptoms of attack.
• In neglected orchards mud galleries can also be seen on the trunks.

Control

• Copious irrigation and drenching nurseries or basin of transplanted seedlings, with chlorpyriphos or quinalphos is recommended.
• Digging the termitaria and destruction of the queen is most important in termite management.

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Mites

Scientific name: Eriophyes guerreronis

Order: Eriophydae

Family : Acarina

Introduction

• Of late mites have started appearing in serious form on coconut in South India.
• Specially in Tamil Nadu, Kerala, Karnataka and border areas of Andhra Pradesh.

Symptoms of damage

Large nuts damaged by Mites

Colonies of mites live under inner bracts of perianth and suck sap from tender tissues. Damage initially appears as a triangular patch at the level of perianth which turns brown later. As the nut grows injury leads to warting and formation of longitudinal tissues on the surface of the nut. Infestation finally results in poor development of nut, reduction in size and kernel content.

Control

• Sprays of dicofol, methyl demeton or triazophos twice at weekly intervals are recommended on buttons and developing nuts on bunches.

Integrated approach for the management of Eriophyid mite Aceria (eriophyes) Guerreronis (keifer) on Coconut

• Removal of dried spathes, inflorescence parts, fallen nuts etc. and burying in the soil or by burning to minimize the pest inoculum. Crown cleaning shall be taken up periodically
• Spraying of sulphur 80% SP @ 6 grams/litre which gives good control of the mite and also it is the cheapest chemical
• Spraying of profenophos 50% EC @ 5 ml or triazophos 40% EC @ 5 ml or methyl demeton 25% EC @ 4 ml or dicofol 18.5% EC @ 6 ml per litre of water or 20 ml neem oil + extract from 20g garlic + 5g soap in one litre of water exercises good control of the pest.
• Spraying of neem formulation (0.15% or 1500 ppm) @ 5 ml/litre of water also controls the pest.
• Combination treatment containing Neem formulation (5ml) with entomopathogenic fungus Hirsutella thompsonii (5g) per tree is also effective.
• Root feeding of monocrotophos (36 WSC) @ 10 ml + 10 ml water per tree also reduces the pest.
• The chemical spray treatment need to be given at 7 days interval and repeated depending on the need. Avoid application of the same chemical and alternate the above treatments.
• Root feeding of monocrotophos may be given in severe cases of infestation.
• All the palms in the locality shall have to be treated irrespective of the infestation.
• Community approach is highly essential to keep the pest under check.

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Red Palm Weevil

Scientific name: Rhynchophorus ferrugineus F.

Family: Curculionidae

Order: Coleoptera

Introduction

• It is the most destructive pest of young coconut palms.
• Unlike the Rhinoceros beetle, the adult weevil is incapable of causing any direct damage to the tree; on the other hand, the early stages of the weevil are passed on the palm and the damage caused to the tree by the weevil larvae is often fatal.
• Another closely allied species of the weevil, R. palmarum, is an equally dangerous pest of coconut palms in the western tropics.

Host Plants Range

• It is commonly found on the coconut palm, the date palm, Phoenix dactylifera the sago palm, Metroxylon sagu, and the toddy palm, Phoenix sylvestris.
• The palmyra palm Borassusflabellifer, the oil palm, Elaeis guineensis, the talipot palm, CoryPha umbraculifera, the sugar palm, Arenga saccharifera, the serdang palm, Livistona chinensis, the nibong palm, Oncosperma tigillaria, the royal palm, Oreodoxa regia and some orna- mental palms also have been reported to be attacked by the weevil.
• In South Travancore it was reported breeding in the aloe, Agave americana.

Distribution

• Rhynchophorus firrugineus is a serious pest of coconut palms in India and Ceylon.
• The distribution of this pest was from India to the Philippines.
• It is quite likely that the weevil is present in other middle east countries where date palms are grown in abundance.
• It is a local sporadic major pest of coconut and other palms throughout India.

Symptomatology

• It is very difficult to detect the presence of the pest infestation in the earlier stages of attack.
• The grub begins its life inside the palm and normally never comes outside.
• Therefore neither the grub nor the damage caused by it can be readily seen.
• Sometimes, a few small holes Occur in the crown or the soft stem from which pieces of chewed fibres protrude and a brownish viscous liquid oozes out.
• In many cases the drying up of the young heart leaves or splitting of the petioles near the area of attack can be observed.
• But most often the attack by the weevil is noticed only when the tree has been fatally infested and is beyond repair.

Description of the life stages

Egg

• The eggs of the weevil are creamy-white in colour, long, oval in shape and slightly broader at one end.
• They are translucent, perfectly smooth and shining.
• The average size of an egg is 2 .62 mm long and 1.12 mm wide.
• The eggs slightly increase in size before hatching and the brown mouth-parts at the narrow end of the egg can be distinctly seen through the shell.

Larva

• The full grown grub is a conical shaped larva, bulged in the middle, and pointed towards both ends.
• The larva is stout, fleshy and apodal.
• The head is brown in colour and pointed downwards.
• Mouth parts are well developed and strongly chitinised, which enable the grubs to burrow into the hard woody portions of the palms.
• The average length of the larva, when fully grown is 50 mm, and the mean width in the middle is 20 mm.
• The freshly hatched young larva is yellowish-white in colour, with pale brown mouth parts.

Cocoon

• The larva constructs a cocoon of fibre.
• The inside fibres are more closely matted together than those outside, which are arranged spirally.
• The interior of the cocoon is smooth and is plastered with a dark coloured secretion.
• The cocoon is oval in shape varying in length from 50 mm to 95 mm and in width from 25 mm to 40 mm.

Pupa

• The pupa is at first cream coloured but later turns brown.
• Its surface is shiny, but greatly furrowed and reticulated.
• The head is bent ventrally, the rostrum reaching the tibia of the first pair of legs.
• The antennae and eyes are quite prominent.
• The average length of the pupa is 35 mm and the width is 15 mm.

Weevil

• The adult insect is a ferrugineus-brown, cylindrical weevil with a long prominent curved snout.
• It varies considerably in size and is about 35 mm in length and 12 mm in width.
• The head and rostrum comprise about one-third of the total length.
• The mouth parts are elongated in the form of a slender snout or rostrum, which bears a small pair of biting jaws at the apical end and a pair of antennae near the base.

Life history

• The fertile weevil starts egg laying generally from the fifth day of its emergence, and the eggs are laid singly in the softer portions of the palms. Sometimes the eggs are laid loose, when there is enough of moist decaying matter in the trunks of the palms.
• The incubation period of the eggs varies from two to five days depending on the prevailing weather conditions.
• When the egg hatches, the rarva begins feeding towards the interior of the palm stems.
• The larvae may be found in any part of the palm, viz., the bole, stem or the crown in case of young plants up to five years old.
• But as the palms advance in age, the grubs are generally confined to the portions of the stem close to the growing point.
• In palms above fifteen years, the larvae are generally found in the stem two or three feet below the crown, in the crown and in the bases of leaf petioles.
• The larval period ranges from 36 to 78 days and is on an average 55 days.
• The fully developed grubs, construct their cocoons by winding around themselves a number of tough fibrous threads to form a stout, compact, elongate-oval cocoon.
• The pupal period varies from 12 to 20 days.
• The weevils after emergence from the pupal cases, remain inside the cocoon, and this period ranges from 4 to 17 days with an average of 8 days. The weevils remain active during day and night and activity is at its maximum from sunrise to 9 a.m. and from 5 p.m.
• Mating takes place at any time of the day and the males and females mate many a time during their lifetime.
• The female generally starts oviposition from the day succeeding pairing, but sometimes this period may be extended upto one week.
• Oviposition continues for about 45 days and during this period the weevil lays on an average 204 eggs.
• The maximum number of eggs laid by a single female was 355 in 42 days and the minimum was 76 in 26 days.
• The weevils of both sexes live for approximately two to three months.
• The complete life cycle from the laying of the egg to the emergence of adult takes on an average 82 days in the West Coast of India. With such a short life cycle and prolific breeding habits, the pest can multiply in geometrical proportions.

Control

Mechanical

• The methods suggested for the control of this pest, by earlier workers were only preventive and mechanical.
• All scars, wounds and exposure of soft parts of palm should be avoided as a prophylactic measure of control.
• In the case of attacked palms the scooping out of the grubs mechanically and dressing the wounds with repellents like tar, lime, etc.
• Cut and burnt the dead and dried palms so that the neighbouring trees may be protected.

Chemical

• Painting raw surfaces of palm with a mixture of 10 ml tar and 10 gm lindane dust prevents egg laying.
• Root feeding with monocrotophos may be followed.

Biological

• Scotia erratica as a parasite of the larvae of Rhynchophorus ferrugineus.
• A species of mites belonging to the family Pyemotidae as an external parasite on the pupae and adults of the weevil.
• This mite feeds by penetrating the integument of its victim with its mouth parts and sucking out the body fluid.
• The mites are unable to pierce through the pupal cocoons and are generally carried inside the cocoons, by the pupating larvae.

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Slug Caterpillar

Scientific name: Latoia lepida,Macroplectra nararia,Contheyla rotunda

Family: Limacodidae

Order: Lepidoptera

Introduction

• Sporadic pest occasionally causing serious damage. Mnararia occurs commonly in Godavari districts, while C.rotunda appears along the west coast.

Marks of identification

• Caterpillars are fleshy, slug-like and have a series of tufts of spines highly irritating to touch, hence called 'nettle grub'.
• Pupation is in a hard shell-like greyish cocoon attached to tree trunks.
• Hole in the cocoon is indicative of adult emergence.
• L. lepida has yellowish green body with a greenish- blue stripe dorsally between two yellow stripes (inset).
• Mnararia has sub dorsal series ofred-tipped tubercles while C. rotunda has "two grey stripes dorsally.

Symptoms of damage

• Caterpillars initially feed gregariously on the leaves and then disperse causing severe defoliation.

Control

• Since young trees of 6-10 years are preferred, these may be sprayed with any of the contact insecticides at a time when the larvae are gregarious.
• Root feeding with monocrotophos also controls the pest.

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