Pineapple: Insect and Pest Management

Mealybug

Pineapple mealybug are ovoviviparous i.e., the eggs hatch within the female and give birth to larvae. They appear as cottony, small, oval, soft-bodied sucking insects. They are in variety of forms, of which pink coloured ones are commonly referred to as pineapple mealy bug. They mainly inhabit on seed material. These bugs have mobility only at younger stage

• Egg: These are minute, varying from 0.3 to 0.4 mm in length. Its development takes between three and nine days.
• Nymph: The nymphal stage contributes to complete dispersal of the bugs since their body is extensively covered with hairs. Hence they are called crawlers. The nymphal period extends up to 40-50 days. The first, second and third instars of larval stages last for 10 to 26 days, 6 to 22 days and 7 to 24 days respectively. Larvae only feed as a first instar and in the early part of the second instar.
• Adult: Adult females have soft, convex, pinkish body. Also their body is surrounded by 17 pairs of wax filaments. Lateral wax filaments are usually less than one fourth as long as the breadth of the body, and those towards the back of the insect are one-half as long as the body. The pre larvi position period for adult females lasts for around 27 days. The larvi position (giving birth to larvae) period lasts for an average of 25 days. They give birth to about 234 progenies but may produce up to 1000 crawlers. She may then live for another 5 days before dying. Duration of adult female varies from 31-80 days with an average of 56 days. There may be as many as 15 generations. Adult males are having a distinguishable number of eight antennal segments. Total life span 95 days.

• Mealy bugs become lethal when their population gets increased since the bugs suck the sap from leaves causing the plant to wilt.
• They are dispersed by ants. The sugary secretions of the mealy bug attract ants and they carry them making it vast spread. Also the excretion of honey inhibits the plants ability to manufacture food, form chlorosis of underlying plant tissues and cause rotting and leaking of fruits.
• When fruits are infested they become entirely covered with white, waxy coating making it unfit for marketing.
• Leaves appear pale green to yellow streaks; tips become brown.
• The predominant symptom is wilting of leaves commencing from the leaf tips.
• Reddish-yellow colour manifests in the wilting areas.
• Mealy bug causes quick wilt (result in yellow or red leaves) under heavy infestation or slow wilt (no definite colour change) in mild attack due to root damage.

• Parasitoids: 1. Anagyrus ananatis, 2.Anagyrus kamali
• Predators: 1. Ants, 2. Cryptolaemus montrouzieri, 3. Rodolia fumida, 4. Scymnus coccivora, 5. Dicyphus hesperus, 6. Dragonfly, 7. Damselfly, 8. Spider, 9. Robber fly, 10. Praying mantis, 11. Fire ants, 12. Lacewings, 13. Cheilomenes sexmaculata

Pineapple scale

Scale insects have three distinct life stages (egg, immature, adult) and may complete several generations in a single year.

• Egg: Adult females produce eggs beneath the scale covering or in a cottony material, and in many cases spend the cold winter months in this stage.
• Larva: Tiny six-legged crawlers emerge from the eggs, move to newer growth on the plant, insert their mouthparts and begin to feed. A scale-like covering produced from waxy filaments and feces then forms over each individual scale.
• Adult: Scale species are identified by the colour and shape of the covering. The covering protects scales from predation by other insects and from insecticides. The male scale is often a slightly different shape than the female and passes through a tiny, winged stage. The casual observer seldom sees winged stages. Females are wingless and usually remain in one place after inserting their mouthparts into plant tissues.

• A symptom of an attack is rust coloured spots.
• The insect is found beneath secretion, which serves as a shield.
• In the case of this insect the scale or protective armor is made up partly of a waxy secretion of the insect and partly of molted skins. The insect itself in the adult stage is quite well buried beneath the epidermis of the plant and hence there is necessity of combating the pest in its early stages.
• During periods of large populations, some scales become so abundant that an infested plant tissue is totally encrusted with insects.

• Parasitoids: Aphytis chrysomphali, Encarsia citrinus, Encarsia perniciosi
• Predators: Rhyzobius lophanthae, Chilocoris infernalis, Pharoscymnus flexibilis, Telsimia nitida, Predatory thrips

Thrips

• Egg: Females have a saw-like structure that helps to make an incision in plant tissue for egg laying. Usually eggs are laid into incisions in the epidermis of the leaves and stems of young plants. Eggs are elliptical, white, approximately 0.02 cm in length, placed singly, just under the epidermis of succulent leaf, flower, stem or bulb tissue. They are whitish at deposition and change to an orange tint as development continues. It will hatch within 4 to 10 days. Hatching young will immediately begin to suck sap and fluids containing nutrition.
• Larva: Larvae as well as the adult insects pierce the leaves and swallow the sap. Pupation takes place in the ground. The emerging adult is about 1 mm long and has a yellow-brown colour with dark cross stripes on the body. There are two larval stages and besides the adults they are the only damaging stages. Larval development is completed in about 9 days.
• Pupa: There are two non-feeding stages called the prepupa and pupa. They do not feed and occur primarily in the soil. Combined prepupal and pupal development is completed in 4-7 days.
• Adults: Adults are 0.02 cm long. Their body colour ranges from pale yellow to dark brown; wings are unbanded and dirty grey. Males are wingless and exceedingly rare. Females live for about two to three weeks and each can lay about 80 eggs. Mating for reproduction is not necessary. Females produce only female offspring without mating. Females can produce up to 80 eggs, that is why large populations can be generated within a short period. The entire life cycle is estimated as three weeks producing 5-10 generations in a year

• Thrips feed on the plant sap by damaging the leaves. The typical appearance of the damage is a silvery-flecked leaf surface which in severe cases turns brown. These leaves cannot sufficiently photosynthesis.
• Small black spots on the leaves, the excrements of the insects, are a sign of thrips infestation.
• Most thrips rest tightly against leaf veins or in crevices. They are primarily active during the daylight hours.
• Thrips are responsible for the transmission of many fungal and viral diseases in plants.
• When infestations are heavy, people and animals will be troubled with stinging thrips.
• These can also have positive effects on plants. A few species prey on destructive mites and scale insects, resulting in the formation of leaf mould.

• Predators: Predatory mite, predatory thrips, Orius insidiosus, Coccinellids etc.,

Pineapple fruit borer

The pineapple fruit borer is considered as one of the principal pests of pineapple. The larvae bore into the fruit causing holes and uneven fruit development. Damage from this pest varies greatly but can reach more than 90% and drier climates seem to favour borer attack. In most cases fruit borer attacks occur during flowering and formation of the fruit, though this borer can attack slips and rarely act as a leaf miner.

• Egg: Eggs are white, circular and slightly flat and approximately 0.8 mm in diameter.
• Larva: Larvae complete their development within the fruit. Burrowing and feeding activities produce visible damage in the form of frass production and a sticky, gummy exudate.
• Adult: The reddish coloured caterpillar penetrates the inflorescence and remains in the tissue for 15 days, tunnelling and destroying the tissue. After this phase it moves to the base of the peduncle changing into a pupa 12 mm long and 5 mm wide with a brown colour and a few dark spots and emerges 7 to 10 days later as a butterfly. As the caterpillar destroys the tissues of the inflorescence a resin coloured liquid gum is exuded from between the fruitlets, which in contact with the air becomes reddish coloured and as it solidifies, turns dark brown. The adult moth has a greyish upper wing surface and a cream colour underneath with a wingspan of 28 mm to 35 mm. The adult can be found during the day or night, flying in a rapid and haphazard fashion. Eggs are laid on flowers from emergence to the end of flowering.

• The fruit borer larvae open galleries in the pulp, producing an oozing called “gummosis” on the outer side of the fruit.
• Insect damage leads to product rejection at the packing plant

• Predators: Mirid bug (Dicyphus hesperus), reduviid bug, big eyed bugs (Geocoris sp) rove beetle, dragonfly, damselfly, spider, robber fly, praying mantis, red ants, lacewings etc.

Bud moth

• Egg: The eggs are hatched in 12 days.
• Larva: The eggs develop to larvae within 50-60 days. They are mobile and avoid light. The organism is infectious at this stage. It has seven instars of growth. The larvae appear as dirty-white and somewhat transparent and have a bright reddish-brown head with one lateral ocellus (small eye) at each side and clearly visible brownish thoracic and abdominal plates. They measured 21-26 mm in length having a diameter of 3 mm. The presence of older larvae can be detected by characteristic masses of bore-meal and frass (excreta) at the openings of bore-holes.
• Pupa: This stage lasts only for 20 days. The pupae are brown coloured and are of 10 mm and formed in a cocoon of 15 mm size. As the maturation progresses the pupae works itself to move to the next adult stage.
• Adult: Its life is only for 6 days. The females lay eggs in crevices of the plant tissue. It lays approximately 200 eggs. The adult is nocturnal and having a length of 11 mm with a wing span of 18-25 mm. They are bright yellowish brown. The forewings may show longitudinal darker brown banding and in the male a dark-brown spot towards the apex. The hind wings are paler and brighter. When they are at rest their antennae are pointed forwards. The life span totally depends on temperature and it gets shortened at warmer conditions causing only eight generations per year.

• Bud moth‟s larvae normally feed on decaying plant parts and further infesting surrounding healthy tissue. Also it attacks leaves and thus destroying the xylem tissues causing the leaves to wilt.
• The total growth of the plant retarded and further the whole plant perished
• A secondary infection of plant parasites and fungal pathogens make the effect more critical.
• When they attack on mature fruit they bore into the peel of the fruit causing exudation of secondary metabolites like gum.

• Predators: Coccinellids, mirid bug (Dicyphus Hesperus), reduviid bug, dragonfly, damselfly, spider, robber fly, praying mantis, red ants, lacewing, big eyed bugs (Geocoris sp), rove beetle

Pineapple fruit fly

• Egg: The female flies lay eggs within the fruit. The eggs are white and are tapered at the ends with a length of about 1.2 mm. They appear in colonies.
• Larvae: They are plant feeders. Sometimes they behave as saprophages invading decayed plant material. They also infest on fruits. They form cavities within the fruit which grow and coalesce and are called “spot with galleries”. All further development of the larvae takes place within the fruit. This further causes fermentation of the fruit. The larvae develop are yellowish white, vermiform and devoid of legs. Their total length is approximately 9.5 mm which is made up of 11 segments. Of which three pairs are at the thoracic region and there is a head region and the eighth at the abdominal region. The head region has small retractable cone shape with internal mandibular hooks. The first segment of the thorax has a pair of anterior spiracles with short extensions 12 to 14 digits. At the caudal region pair of posterior spiracles presents. Each of them has three openings surrounded by esclerotizada. At the outward area from them form a series of projections in the form of hairs called inter spiracular processes. The larvae mainly inhabit at the shell and fleshy part of the fruit.
• Pupa: Larvae continued to inhabit in fruits until the pupa state. Pupa stage lasts 15 to 20 days under laboratory conditions. The pupae are reddish brown, cylindrical capsule also with 11 segments. They project to a length of 5 mm with a diameter of 1.8 mm. The spiracles present are distinctive in nature and have well defined cephalic area.
• Adult: They have conspicuously pictured wings with metallic blue or greenish colour on the body and legs. Also they are ovipositors and lay eggs in fruits. Adult grows up to 5- 6.5 mm long having wingspan of about 1 cm. They are black coloured with abundant micro pubescecias. They have wide and short scuttellum. They presents with thorny hind femora of equal thickness. Their wings are clear devoid of any protrusions. It has a dark spot along its entire length. This extended to the wing margin and divide at the subcosta. The radial vein appears dark and cubitoanal cell is somewhat round.

• Pineapple fruit fly as the name defines it mainly infests fruits.
• The fruit damage starts when the female fruit fly punctures the fruit with its long and sharp ovipositor.
• The fruit skin is breached, and bacteria enter and the fruit starts to decay.
• The larvae that hatch from the eggs feed on the decaying fruit tissue, and on the yeasts and bacteria that multiply in it. Also the larvae groove into the pineapple.

White grub

• Egg: Eggs are usually 1.5 to 3 mm in diameter, oval in shape and found encased in soil aggregates. The egg is dull, small, spherical, pearly white that darkens just before hatching. The 20-24 mm long pupae may be creamy white, pale yellow or dark brown.
• Larva: Older scarab larvae develop within the soil among the roots of their pineapple. They feed upon organic matter within the soil as well. Although white grubs are not immobile, they do not disperse far from where the eggs were laid. White grubs are easily identified by their white or ivory-coloured, „C‟-shaped bodies, which are soft and plump. The posterior quarter to third of the larval abdomen is commonly a dark blue-grey colour, due to the contents of the digestive system. Fully grown grubs of larger species are 2.5 cm or more in length.
• Adult: The adults are fairly heavy-bodied insects; most of them with long, spindly legs. They range in colour from light, reddish-brown to shiny black and in size from 12-25 mm in length.

The usual duration of one complete generation (adult to adult) is 2 to 4 years depending upon latitude. Generations, however, are staggered so that grubs and beetles are present every year. Grubs are usually most numerous and damaging the second season following a large beetle flight. With the exception of the common May or June beetle, which has a three-year life cycle, the life history of the beetles mentioned above is completed in 12 months

• White grub infestations can destroy roots, causing the affected area to become spongy, which allows the sod to be rolled back like a piece of carpet.
• Evidence of grub damage, including patches of dead or dying turf, are visible during spring (April and May) and late summer and fall (September and October).

Fig beetle

• Egg: Females lay eggs (app. 60) in August and the eggs develop into larvae after 12 days and are especially attracted to compost and manure piles. Their eggs are whitish in appearance and be easily found over the soil.
• Larva: They have head and legs. They live on soil surface and have a length of 2 inches. Their life includes three instars of which first and second get completed by autumn and the final in the spring season of second year. At rest they curl into C shape. When the larvae get matured they become 2 inches long and become cream coloured. The body of larvae is stiff with brown hairs at the back of the thorax. These hairs are used for locomotion. They form hollow cells in the soil and pupate there.
• Pupa: After a few days it reaches a size of 12-50 mm. They develop by June- July. Its duration extends from 25-27 days. The pupae are of size 15 X 25 mm. They are whitish at initial stages and further change to cream coloured as that of larvae stage. At the maturing stages they slightly shift the colour to green.
• Adult: They develop by June- November. They lay their eggs in soil. They are white coloured and large sized approximately 12-50 mm in size. They feed on organic matter in soil surfaces. Adults are velvet green in colour. They occupy brownish bands around the edge of the wings and a bright metallic green at the ventral side. Adult females are 17 X 25 mm and adult males are 13 X 22 mm size. At the head portion they are equipped with horn like projections for penetrating into the fruit skin. Adults are tremendous fliers.

• The plant part affected mainly includes flower parts like pollen, nectar and petals, fruit and larvae damage roots.

Pineapple weevil

• Egg: The eggs are oviposited singly in shallow excavations made usually in the fruit stalk at the junction of the stalk and fruit of the pineapple. More rarely, females lay eggs at the base of the crown and in the basal shoots. The eggs are oval, dull, white and semitransparent.
• Larva: The larvae hatch in eight to ten days and tunnel upward in the rootstock or fruit stalk or in the fruit itself. The larval stage lasts for eight to ten weeks. The larvae are white except its head which is brown coloured. It grows to a size of 2.5 cm. The larvae of the pest are infective. It is motile and move up and down destructing the inner tissue of the flower stalk. This affects the normal growth of the fruit causing lack of crown.
• Pupa: The pupa is formed at the extremity of the tunnel lasting 18 – 24 days.
• Adult: The adults are poor fliers and require a great deal of protection from the direct rays of the sun. It prefers a very humid environment as it shows a preference for the recesses of dense vegetation. They are approximately 16.5mm – 22mm long. The female weevils lay eggs inside a hole within the plant part like base of the crown or base of the shoots. Adults appear 10.6 – 18.2 mm long. They are black or brown coloured with no scales over the body. They feed on leaves causing necrotic edges. Sometimes the fruits they attack rot.

The life cycle completed within 3 – 4 months

• The whole life span of the weevil occurs in the same plant.
• The female lays single egg in the slit created by them in the plant leaves. The larvae move to the stem causing tunnels in the plant.
• The larvae pupate in the central stem. There they make cocoon around the body for its growth. If the plant tissue remains enough the adult develops on the same host plant.
• The infestation causes the exudation of a gelatinous material which is protective for the weevil slits. The damage to the host plant includes adult feeding marks on the leaves, leaves browning, decomposition of base of central leaves

Pineapple red mite

• Egg: Orange in colour
• Larva: The larvae are pale and almost translucent. They often have three pairs of legs in the larval stage and four pairs of legs in the nymph and adult stages.
• Adult: Adults, nymph and eggs of this species are bright orange in colour when alive. The adult mite is approximately 0.3–0.4 mm long and 0.1 mm wide. When present on the plant, the mite is always found on the white basal portion of the leaves, where it feeds, particularly on the crown.

• These cause damage to leaves and fruits. Severe infestations produce large, dark brown lesions that almost cover the basal white tissue which can lead to necrosis and death of the leaves.
• In pineapple-production areas, it may frequently cause severe damage to recently established plants in the field.
• Plants that are infested in the early stages remain small and fruit production is either curtailed or non-existent. Heavily infested plants may die before producing fruit.
• It feeds the epidermal tissue to dry and crack which allows fungus and bacteria to enter the plants and cause the tissue rot and scarring and tissue malformation

• Predators: Syrphid/hover fly, Predatory gall midge (Feltiella minuta)

IPM for Pineapple

To know the IPM practices for Pineapple, click here.

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