Hairy caterpillars

Hairy caterpillars of cardamom are a group of defoliators that appear sporadically and cause severe damage to the crop. Incidence of these pests was reported by Puttarudriah (1955), Rajan (1958), Ayyar (1961), John (1967), Joseph etal. (1983) and Selvan and Singh (1993). Nine species of hairy caterpillars are known to infest cardamom. They are Eupterote canaraica Moore, E. cardamomi Renga, E. fabia Cram., E. testaceae Walk., E. undata, Linodera vittata Walk., Euproctis lutifacia Hamp., Alphaea biguttata Walk. and Pericallia ricini Fabr. Biology of different species of these hairy caterpillars were described by Nair (1975), Kumaresan et al. (1988), Singh et al. (1992) and Selvan and Singh (1993). The different Eupterote sp. has striking similarities. They are polyphagous larvae, voraciously feeding on shade-tree leaves at early stages and on cardamom leaves at late stages, and have extensive larval period consisting of seven-ten larval instars. They congregate on tree trunks or on cardamom leaves. Eupterote cardamomi, E. undata and E. canaraica are the most destructive among them.

2.5.1 Eupterote cardamomi

Adults of E. cardamomi emerge from their pupae in June with the commencement of monsoon rains. The moth is brown in colour with double post-medial black lines and several light wavy lines on wings. Female is bigger (wing span of 90 ± 3.3 mm across and 36 ± 1.27 mm along body axis) than the male (wing span of 85.50 ± 1.45 mm across and 36 ± 1.27 mm along body axis). Antennae of the male are plumose while that of female is filiform. Males live longer than the females by 1 or 2 days. Females after pairing lay as many as 563 eggs in batches as clusters during their oviposition period of 5-8 days. Eggs are spherical with flat base, yellow and remain glued to the substratum. The chorion is hard and sculptured. Incubation period lasts for 20-25 days. Nearly 75 per cent of the eggs hatch, the neonate larvae cut a circular hole mid-dorsally and emerge out and they feed on empty egg shells. The first instar is yellowish with pale-brown head, 5.41 ± 0.15 mm long, gregarious and becomes a fully grown larva through 10 instar stages in 125-148 days. A fully grown larva measures nearly 77 mm in length, bears on its body tufts of long white-tipped black hairs on dorsal verrucae armed with needle-like hollow setae, which causes considerable irritation when pricked. The caterpillars, up to their sixth or seventh instar stage remain feeding on shade-tree leaves, from where they descend by silken thread to cardamom plants. The larvae are nocturnal, defoliating cardamom leaves from its margins, leaving only midrib. Prior to pupation, larvae stop feeding, enter 2-5 cm deep in soil, congregate in groups of 5-10, and become sluggish. The larvae after 3-6 days of pre-pupal period pupate inside cocoons spun with silken thread, debris and larval body hairs. The pupae are adecticous, obtect with spindle-shaped body and are dark brown in colour. They measure roughly 30 mm in length and 12 mm in width and have a long duration of 212-230 days. The entire life cycle is completed within 365-410 days.

2.5.2 Eupterote undata

Moths of E. undata are brownish-yellow or yellow, with black double post-medial lines and many black wavy lines on wings. Wingspan of female is 7 cm and that of male is 6.5 cm. Female moths have a longevity of 3-4 days, one day more than that of males. Female moths lay 140-350 eggs in clusters of 80-100, firmly glued to undersurface of leaves of shade trees. Eggs are pale yellow, hemispherical with a flat base, measuring 1.34 ± 0.03 mm in diameter and 1.14 ± 0.08 mm in height. Eggs become dark green towards the close of its incubation period of 20-24 days and yellowish; first instar larvae emerge out from 95 per cent of eggs. First instar larvae are black headed, bearing dorsally four rows of black dots from where tufts of hairs originate. They possess three pairs of thoracic and five pairs of abdominal prolegs. Two days after emergence, they start feeding at night voraciously on leaves of shade trees. During daytime they remain inactive in compact congregations on barks or leaves of shade trees (Fig. 8.8). They remain on shade trees till they become fourth or fifth instar larvae. Then they descend to cardamom plants by silken threads and defoliate the plants leaving only mid ribs. The larvae become black by this time, their thoracic legs become black, abdominal legs pale red, and the whole body gets covered with gray hairs, which upon contact cause irritation. They undergo eight moults within 182-202 days of larval life and fully developed ninth instar larvae of about 11 cm lengths are formed. They stop further feeding and move about during their pre-pupal period of 2-3 days in search of suitable sites for pupation on tree trunks or in soil. At pupation they enclose themselves in a self-made flimsy cocoon of larval hairs and soil particles. They shed the larval skin and become pupae, which appear dark brown, roughly oval and obtect. The pupal period lasts for about 65 days. The entire life cycle is completed within 265-294 days. Selvan and Singh (1993) noticed Eugenia hemispherica, Coffea arabica, Maesa indica, Macaranga indica, Veronia arborea and Persia macrantha as alternate hosts of E. undata. Ingestion of cardamom leaves sprayed with 1 per cent aqueous suspension of the extract of Lantana camara produced larval and pupal mortality in E. undata under laboratory condition (Gopakumar etal., 1996).

Lenodera Vittata
Figure 8.8 Hairy caterpillar: aggregation of the hairy caterpillar of cardamom, Eupterota undata on a shade tree.

2.5.3 Eupterote canarica

Moths of E. canarica emerge in June-July. The moths have dark wings of an expanse of 6.7 cm with post-medial lines on each. Female moths lay about 480 eggs in groups of 40-120 during its 9-12 days oviposition period. Eggs are light yellow, hemispherical, having a diameter of 1.5 mm and height 1 mm. After an incubation period of 20 days, larvae emerge out, which grow up to the second or third instar stages by feeding on leaves of shade trees. The third or fourth instar larvae descend to cardamom plants, feed on cardamom leaves and grow through successive stages to the fully-developed larvae, taking altogether 4-5 months to complete the larval period. A full-grown caterpillar is about 62 mm long with dark brown body, red head and prothoracic shield. They pupate in soil inside oval cocoons made by the last instar larvae with sand, debris and body hairs. After 7-8 months pupation, adults emerge. The caterpillars may get parasitised by Sturmia sericariae and infected by an entomogenous fungus (Nair, 1978; Kumaresan, 1988).

2.5.4 Eupterote fabia

Moths of E. fabia are brownish-yellow in colour with distinct post-medial black lines and wavy lines on wings. It has a wingspan of 12 cm. A fully-grown caterpillar is 7.5 cm long with black head, gray-tipped hairs and red prolegs. Pupation takes place in a self-made cocoon consisting of silk, sand particles and body hairs. Pupae measure 31 X 12 mm and the pupal period lasts for 7-8 months. Infestation on cardamom occurs usually during August-October (Nair, 1978; Kumaresan, 1988).

2.5.5 Eupterote testaceae

Caterpillars of E. testaceae cause only mild damage to cardamom. Its moths have yellowish wings with faint wavy black lines on it. Moths emerge usually in June—July and during its oviposition period of 8—9 days lay nearly 350 pale yellow eggs in clusters of 60—90 on adaxial surface of leaves of shade trees. Eggs are hemispherical with a diameter of 1 mm and height of 0.5 mm. Larvae hatch out of the eggs on 13th—15th day of incubation. The larva undergoes six moults and becomes fully grown in 100—106 days, measuring 7.2 cm in length. The grown-up caterpillars have pale yellow head, streaked with black lines and each segment bears dorsally conical tufts of short gray hairs and long white tipped hairs. A silvery white line on the mid-dorsal side is bordered on either side by red lines. On lateral side of the body is a longitudinal broad red band. They pupate inside loose cocoons made of silk, sand and body hairs. After a pupal period of nearly 8 months, adults emerge (Nair, 1978; Kumaresan, 1988).

2.5.6 Lenodera vittata

Adults of L. vittata are thickset moths with under-developed wings having a span of 5.6 cm. The adults emerge in June, lay eggs in single rows on cardamom leaves. A female may lay a maximum of 130 eggs during its oviposition period of 6—9 days. The eggs are off-white in colour, dome-shaped, with a diameter of 2.9 mm and a height of 1.6 mm. Chorion is leathery and translucent. After an incubation period of 10—13 days, caterpillars emerge out of the eggs which by feeding on cardamom leaves become fully grown in about 120 days, attaining a length of 106—110 mm. Dense capitate hairs cover its body. A pair of transverse rows of black bristles is present dorsally on each segment. On its meso- and meta-thoracic segments are long yellow hairs and from the dorsal, lateral and ventro-lateral spots arise black bristles. Fully-grown caterpillars, during their pre-pupal period, burrow in the soil around the plant base to a depth of about 6 cm and then pupate. Pupae are 32 mm long and 14 mm broad. Pupation is completed in 5—7 months. The parasite Carcelia kockiana is seen to parasitise the larvae (Nair, 1978; Kumaresan, 1988).

2.5.7 Euproctis lutifacia

Its hairy caterpillars infest tender foliage of cardamom. Adult is a vinous brown moth. Its wings have a span of 4 cm with an antimedial orange-red line over it. Fully-grown caterpillars are about 3 cm long, pale-brownish with a mid-dorsal black line. First and second abdominal segments bear tufts of brown hairs mid-dorsally. An eversible glandular organ is located on the dorsal surface of the seventh abdominal segment. Fully-grown larvae metamorphose into pupae inside a silken cocoon in soil. After a pupal period of 16—18 days, adults emerge generally during December (Nair, 1978; Kumaresan, 1988).

2.5.8 Alphaea biguttata

This is an arctiid black hairy caterpillar infesting cardamom. Its moths are comparatively small, having a wingspan of about 5 cm with a curved white band along its forewings. Fully-grown caterpillar is 6—7 cm long. Pupation takes place in a self-made black silken cocoon made of soil particles and body hairs. Adults emerge after about 22-23 days of pupation (Nair, 1978; Kumaresan, 1988).

2.5.9 Pericalia ricini

Moths are medium-sized. Forewings have pale red rings, wings and abdomen are crimson coloured. Black bands are present on its crimson coloured abdomen. Females lay about 170 eggs in clusters on under surface of leaves. After an incubation period of 4-5 days, dark brown larvae, bearing fine long reddish-brown hairs on bluish warts emerge (Nair, 1978, Kumaresan, 1988).

Beeson (1941) reported Bombax malabaricum, Careya arborea, Cedrella toona, Dalbergia volubilis, Erythrina indica, Shorea robusta, Tectona grandifolia, T. grandis, Terminalia sp. and Vitex negundo as alternate hosts of hairy caterpillars. These caterpillars congregate on tree trunks or cardamom plants during daytime and can be collected in large numbers and destroyed. Sekhar (1959) recommended fish oil rosin soap sprays against the pest. Nambiar et al. (1975) found BHC 0.2 per cent or malathion 0.1 per cent or carbaryl 0.1 per cent effective for its management. Collection and destruction of moths using light traps and spraying methyl parathion 0.1 per cent are also recommended (Anonymous, 1985a). The natural enemies of hairy caterpillars reported include Apanteles tabrobanae Cram., Sturmia sericariae, Aphamites eupterotes, and Beauveria sp. (Rajan, 1965; Nair, 1975; Varadarasan, 1986).

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