Large Cardamom: Insect Pest Management

2016

More than 22 insect pests are known to be associated with Large cardamom, and only a few of them cause substantial damage to the crop ().

Leaf caterpillar

Leaf eating caterpillar (Artona chorista Jordon, Lepidoptera: Zygaenidae), is a major pest of Large cardamom in Sikkim and West Bengal (). Its outbreak was recorded in 1978 in Sikkim where about 2000 acres of Large cardamom plantations were severely defoliated (). The leaf caterpillar is first recorded as Clelea plumbiola Hampson on large cardamom by Bhowmik ().

  1. chorista occurs sporadically in epidemic form in Sikkim and West Bengal every year. Usually the incidence of the pest is observed from June to July and October–March in the field. Severe damage was recorded in Lower Dzongu, Phodong, Ramthung Basti (north Sikkim), Soreng, Hee, Chako (west Sikkim), Kewizing (south Sikkim); Assamlinzey, Dalapchand and Rongli (east Sikkim) and Gotak (Darjeeling Dist. of West Bengal).

Nature and extent of damage

The leaf caterpillars are monophagous and highly host specific. The caterpillars are gregarious in nature (60–200 caterpillars/leaf) and feed on chlorophyll contents underneath the leaf, leaving transparent epidermis and veins (skeletonization). The damaged portion of the leaf becomes brownish and which can be identified easily (). The mature larvae completely defoliate the plant leaving the midrib of the leaves. Defoliation of the plant by the pest affects the yield indirectly. The area of a medium-sized cardamom leaf is about 160–170 sqcm and a mature larva consumes about 2.12 sqcm cardamom leaf in a day ().

Biology

The adult is a moth, black and very small in size (10–15 mm). The male moth can easily be distinguished from female with its bushy antennae, white bands on the abdomen and smaller size. The sex ratio is recorded as 1 female : 2.2 male. Adults copulate in tail-to-tail position during night; they survive for 10–12 days in captivity. The female moth lays 250–300 eggs in clusters on underside of cardamom leaves. Eggs are smooth, round in shape, small, translucent and cream in color. The eggs hatch in 20–22 days in April–May. The immature larvae are greenish-yellow and mature larvae are dull yellow and measure 20–25 mm in length (Table Life cycle of leaf caterpillar, Artona chorista on large cardamom). The larvae bear small setae and dark brown longitudinal stripes along the dorsal side.

The larval period is completed in 58–62 days during monsoon i.e. May–July in first generation and 170–190 days (about 6 months) from October to March in the second generation. The larvae diapause from the middle of December to February by covering under the web on dry cardamom leaves and then pupate in pale brown silken cocoon (for about 25–30 days) in July–August and 35–40 days in March–April. Moths emerge in April–May and August–September).

There are two generations of A. chorista in a year. First generation takes about 4 months i.e. from May to August (egg to adult) and second generation about 8 months i.e. from September to April.

Table Life cycle of leaf caterpillar, Artona chorista on large cardamom

Stages and other parameters I Generation

(April–July)

II Generation

(August–March)

Incubation period (days) 20–22 24–26
Larval duration (days) 58–62 170–190
Pupal duration (days) 24–28 35–40
Adult longevity (days) 10–12 10–12
Total life period (days) 112–124 (About 4 months) 239–268 (About 8 months)
Minimum temp. range (°C) 8–17 2–18
Maximum temp. range (°C) 20–30 12–28

Management

Mechanical control: The larvae are gregarious in nature and feed underneath the cardamom leaf; the infested leaf can easily be identified from a distance and these can be collected along with larvae and destroyed in June–July and October–December. A demonstration trial in planters’ fields at Phodong (north Sikkim) where 97 per cent and 86 per cent infestation was recorded in 1996 and 1997, has given 58 per cent and 67 per cent control over the initial infestation in both years (Table Pre- and post-treatment observations on demonstration trial on mechanical control of leaf caterpillars, Artona chorista). Group approaches of mechanical control by all the farmers of the locality, when the outbreak is observed, totally suppress this pest in an area within a few years.

Table Pre- and post-treatment observations on demonstration trial on mechanical control of leaf caterpillars, Artona chorista

Particulars 1996—97 1997—98
Pre-treatment observation Post-treatment observation Pre-treatment observation Post-treatment observation
Clumps infested 95.0% 36.92% 86.0% 19.0%
Tiller infested 33.21% 4.38% 22.38% 1.61%
Damage on leaves/clump 1–37 1–11 1–23 1–6
Mean leaves damaged/clump B.14 ± 0.72 1.20 ± 0.30 5.39 — 0.59 0.36 ± 0.09
No. of caterpillars/leaf 66–192 16–136 22–236 8–86
Mean no. of caterpillars/leaf 127.91 — 11.80 67.52 ± 10.14 97.47 ± 13.15 33.40 ±7.84

Biological control: A species of predatory pentatomid bug was recorded on the leaf caterpillar in the field. It kills 1–3 larvae/day by sucking their body fluid. Two larval-pupal parasitoids, Medina sp. and genus of Bactromyra (F. Tachinidae) were recorded. Single black color adult fly emerges from a cocoon of leaf caterpillar after 22–24 days of pupation. There was 7.08 per cent field parasitization. Two larval-pupal hymenopteran hyper parasitoids (Venturia sp. and Mesochorus sp. (F. Ichneumonidae) were also recorded. Venturia sp. is black and 6–8 mm in size whereas Mesochorus sp. is brown and 5–7 mm in length. Yadava et al. () have reported two hymenopterans viz., Apanteles sp. and Dolichogenedea sp. ( F. Braconidae) an endolarval parasites on A. chorista. These natural enemies kill the larvae and pupae of the pest and reduce the pest population considerably in the field.

Chemical control: Even though insecticides like Quinalphos and Endosulfan (0.05 per cent) are effective, growers are advised to avoid use of such chemicals, which kill the natural enemies also. This crop is not exposed to any chemical insecticides (). Therefore naturally-occurring parasitoids keep the pest population under check. If at all required any one of the following insecticide can be sprayed:

(a) If caterpillars are in early stage (skeletonization of the leaves) Quinalphos 25 EC 0.05 per cent (200 ml/100 l of water). Endosulfan 35 EC 0.05 per cent (143 ml/100 l of water).

(b) If the caterpillars are in the later stage (defoliation of the plant) Quinalphos 25 EC 0.1 per cent (400 ml/100 l of water). Endosulfan 35 EC 0.1 per cent (286 ml/100 l of water).

(c) If the infestation is very severe, second round of insecticide spray after 1 month can be given.

During rainy season, 50–100 ml wetting agent per 100 l of water is added with insecticide solution.

Hairy caterpillars

Hairy caterpillars are a group of defoliators infesting Large cardamom. Severe infestation by hairy caterpillars affects the crop yield. Among the hairy caterpillars, Eupterote sp. Are the predominant ones found in cardamom plantations. The major species are: Eupterote fabia Cramer and Eupterote sp. (Lepidoptera: Eupterotidae).

Incidence of hairy caterpillar is recorded during post-monsoon period i.e. from August to December. E. fabia and other species are sporadic and polyphagous and feed on the leaves of cardamom causing defoliation. Sometimes, E. fabia causes severe damage of the leaf.

Biology and management

The adult moth of E. fabia is large (10.8 cm across the wing) and yellow in color. The female moth lays eggs on the underside of leaf in clusters of 20–140 eggs. The hatching period lasts for 19–21 days. The mature larvae measure 7.4 cm in length. The larval development is completed in 83–97 days. The pupation takes place in soil in a silken cocoon. Adult comes out in 120–180 days (). Hairy caterpillar is a minor pest.

Aphids

The aphids cause more damage as a vector rather than as a pest. The aphids are associated with the transmission of viral diseases (Foorkey and Chirke) of Large cardamom. The aphid population is recorded high during summer months at lower altitudes. The major species are:

1 Pentalonia nigronervosa f. caladii (Goot) (Hemiptera: Aphididae).

2 Micromyzus kalimpongensis (Hemiptera: Aphididae).

3 Rophalosiphum maidis (Fitch) (Hemiptera: Aphididae).

4 R. padi (Lin.) (Hemiptera: Aphididae).

P.nigronervosa f. caladii and M. kalimpongensis are known to be the vectors of Foorkey or virus yellow disease. The aphids colonize at the base (rhizome) of the clump and if population is more, they move to the aerial portion of the clump. Two to six aphids/tiller were recorded from the Foorkey infected plants during summer months. P. nigronervosa f. caladii is also reported as the vector of Katte viral disease in small cardamom. These aphids are dark brown in color, small and measure 1–1.5 mm in length. They remain mostly inside the soil close to rhizomes and suck the sap from the pseudostem. The alate (winged) and apterous (wingless) forms complete life cycle in 20–30 days.

Maize aphids, R. maidis and R. padi are reported on the lower surface of the leaves of large cardamom, congregating near the mid-rib and veins. These aphids are known to be the vector of another viral disease, mosaic streak or Chirke ().

The removal and destruction of diseased plants is helpful in control of further spread of disease and in reduction of aphid population. Spraying of 0.03 per cent Dimethoate or Phosphomidon after removal of Foorkey and Chirke affected clumps in March–April, gives adequate control of aphids.

Shoot fly

Shoot fly, Merochlorops dimorphus Cherian (Diptera: Chloropidae), recorded as a major pest of Large cardamom is damaging young shoots. Low to moderate damage by shoot fly is recorded in Large cardamom plantation in Sikkim and West Bengal. In the main field, more damage is recorded at higher altitudes than in the lower. Kumar and Chatterjee () have reported another species of shoot fly, Bradysia sp. (Diptera: Sciaridae), damaging large cardamom. The pest is recorded throughout the year in Large cardamom growing tract. The incidence was as high as 56 per cent of new shoots.

The tip of the shoot becomes brown and later whole shoot dries up causing ‘dead heart’ symptom. Single, pale glossy white larva bores the young shoot and feeds on the central core of pseudostem from the top to the bottom resulting in its death. The mature larva measures 8–10 mm long and pupates inside the infested stem. The pupal period lasts for 20–24 days and adult survives for 4–6 days in the laboratory condition. The adult fly is smaller (5–6 mm) in size and brownish yellow in color.

For managing this pest, infested young shoots should be removed at ground level and destroyed.

Stem borer, Glypheterix sp. (Lepidoptera: Glyphiperidae)

It is a minor pest and is specific to Large cardamom. Eventhough Azad Thakur and Sachan () recorded 19 per cent infestation of stem borer in 1978–79, the incidence is very low in main cardamom plantations but sometimes it causes considerable damage in nurseries. Stem borer is recorded from March to November at Ghotak (West Bengal), Pangthang, Khasay, Gamdong (east Sikkim), Kabi and Mangan (north Sikkim). The larvae feeds on the central portion of the shoot and as a result the terminal leaf of the plant gets dried up and this symptom is known as ‘dead heart’. Infestation of this pest is also indicated by the presence of entry holes plugged with excreta. The intensity of infestation has been found higher at lower altitudes (about 5 per cent) in Sikkim on seedlings and main plantations. It is a minor pest and can be controlled by removing i.nfested shoots along with caterpillars

White-grubs Holotrichia sp. (Coleoptera: Melonthidae)

It is a polyphagous white grub infesting roots and rhizomes of Large cardamom. The infested plant shows yellowing of leaves and withering symptoms. The grubs are white and ‘C’ shaped with brown head. The incidence was recorded at Panthang (East Sikkim and Kabi (North Sikkim) in September–December. This is a minor pest, hence no control measures are adopted

Leaf folding caterpillar

This feeds on chlorophyll contents inside the folded cardamom leaf (). It’s damage is very minor in nature, and was observed during July–December in east and north Districts of Sikkim. The caterpillar pupates inside the folded leaf during winter. Adult is a medium sized (24–28 mm across the wing), brownish yellow moth. Cotesia euthaliae Bhatnagar (Hymenoptera: Braconidae), was recorded as larval parasitoid. For control infested leaves along with caterpillars are collected and destroyed.

Minor pests

Mealy bugs

These occur on underground rhizome of the Large cardamom plants. They feed on the roots and rhizome part of the plant and cause yellowing during summer months. The pest is recorded at Neem (East Sikkim), Tarku (South Sikkim), Chawang (North Sikkim) and Singling (West Sikkim) in March–October.

Leaf thrips

Heliothrips haemorrhaidalis Bouche (Thysanoptera: Thripidae), is a minor pest on leaves, infests the undersurface of leaves and suck the sap. The damage is more on seedlings and are recorded throughout the year. Rhipiphorothrips cruentatus Hood (Thripidae: Thysanoptera) is also reported as a minor pest of Large cardamom on seedlings (). The leaf thrips population is more on lower surface compared to the upper surface. The infested leaves turn brown and wither out gradually. For management, infested leaves are removed and destroyed. If infestation is severe it can be controlled by spraying Monocrotophos or Quinalphos at 0.025 per cent ().

Lacewing bug

Stephanitis typica (Distant) (Hemiptera: Tingidae), is a minor sucking pest on large cardamom leaves. Severe infestation was recorded in 1997 in north Sikkim where about 1000 plants in an isolated patch was damaged. The infested area was open without any shade trees. The damage is recorded in main field where shade was thin during pre- and post-monsoon period. The infestation is recognizable even from a distance due to its grayish yellow feeding spots on the leaves. The bugs suck the sap on lower surface of the leaves. So, in case of severe infestation, plant growth and yield gets affected ().

Grasshoppers

Grasshoppers are of minor importance and present in main field and nurseries. Both nymphs and adults feed on the leaves. The major species are: Mazarredia sp. Bolivar (Tettigonidae) and Chrotogonus sp. (Acrididae)

Bagworm

Acanthopsyche sp. (Lepidoptera: Psychidae), is a minor pest. It’s larvae cause small holes in the cardamom leaves. The insect was recorded throughout the year in most of the plantations but damage is negligible.

Fruit borer

The grub of Scolytid beetle (Synoxy sp.) makes a hole in the immature capsule and feeds on the seeds inside and pupates inside the capsule. The pest was recorded at Hee Gaon (West Sikkim).

Scale insects

The scale insects colonize near the mid vein on lower surface of the leaf. They suck sap, which results in brownish spots on leaves. Minor infestation of scales was recorded in seedlings at Cardamom Nursery, Mallipayong (South Sikkim).

Rhizome weevil

Adult is about 1.5 cm brownish weevil feeding on rhizome by making tunnel. It is a minor pest and was recorded at Kabi (North Sikkim) in April.

Leaf beetle

The adult, Lema sp. (Coleoptera: Chrysomelidae) are greenish brown in color and 8–10 mm in size and make irregular holes in tender leaves.

Green beetle

Green color beetle, Basilepta femorata Jacoby (Coleoptera: Eumolpidae), is recorded in April and October on Large cardamom leaves. It’s exact nature of damage on large cardamom is not yet known. The grub of Basilepta fulvicorneis is a major pest on cardamom (Elettaria cardamomum Maton) (). However, Azad Thakur and Sachan () reported that adult beetles are very destructive as they nibble and eat away fresh leaf buds.

Nematodes

Root knot nematode, Meloidogyne incognita, is found to infect seedlings/plants in nurseries and plantations causing considerable damage. The affected seedlings/plants show stunted growth, the leaves become narrow and arrange in a rosette due to reduction in internodal area. The root system shows excessive branching with galls. Deep digging and exposing the soil to sun (solarization) before preparation for nursery may reduce the nematode intensity. Use of the same site for nursery maintenance is avoided. Farmers are encouraged to change nursery sites every year and to raise seedlings in polybags containing good potting mixture. This practice not only reduces nematode incidence but also prevents movement of nematode through soil from one location to another.

Other pests

Rodents, squirrels and wild cats damage the fruits before harvesting. Black cats (Kaala) a nocturnal mammal is known to cause heavy losses as they are voracious feeders of near-maturing capsules.

Storage pest

A reddish brown caterpillar of cardamom moth, bores into the capsule and feeds on the mucilaginous seed coat; however the hard seeds are unaffected; the appearance of capsules as well as seed quality is adversely affected.

 

Selections from the book: “Cardamom. The genus Elettaria”. Edited by P.N. Ravindran and K.J. Madhusoodanan. Series: “Medicinal and Aromatic Plants — Industrial Profiles”. 2002.