Large cardamom: Insect and Pests Management

Leaf thrips

• Egg: The adult female lays eggs on the leaf or fruit surface. Just before hatching the egg blisters. The eggs are white and banana-shaped and are inserted singly in plant tissue
• Larva: The early larval stage is whitish with red eyes. Larvae become yellowish after feeding. Mature larvae average about 1 mm in length. There are two larval instars and then it moults to the prepupal stage which is light yellow with red eyes and short wing pads
• Pupa: The pupal stage is slightly larger, with longer wing pads and larger eyes. It is yellowish and then darkens with age. The antennae are bent backward over the head in the pupal stage. The prepupal and pupal stages do not feed.
• Adult: As it matures into an adult, the greenhouse thrips' head and thorax darken to black while the abdomen changes from yellow, yellow-red, brown, and black. Cool temperatures retard the color changes. The legs remain a light yellow, and the antenna has eight segments. The greenhouse thrips is parthenogenic, in that it reproduces without mating, and males are seldom seen. It is a poor flier and remains in the shaded areas on the plant almost all the time.

• This pest feeds primarily on the foliage of ornamental plants.
• It attacks the lower surface first and, as feeding progresses and the population increases, the thrips move to the upper surface.
• The leaves become discoloured and develop distortion between the lateral veins.
• Severely damaged leaves turn yellow

• Parasitoid: Megaphragma mymaripenne,
• Predators: Predatory thrips (Franklinothrips orizabensis, F. vespiformis, Leptothrips mali)

Rhizome weevil

• Egg: Eggs are laid in cavities made on rhizome. Egg period 8 -10 days
• Grub: Larvae feed inside the rhizome, larval period 21 days. Pupate in the feeding tunnels
• Pupa: pupal period 21 days. Adult is a brown weevil, 12 mm in length
• Adult: is a brow weevil, live for 7 – 8 months. Only one generation in a year.

• Grubs tunnel and feed on the rhizome causing death of entire clumps of cardamom.

Aphid

• Egg: Eggs are kidney shaped laid singly in the tender part of the leaf sheath, racemes
• Nymph: Nymphs tiny, slender, fragile and straw yellow in colour
• Adult: Minute, dark greyish brown, 1.25 to 1.5 mm long and with fringed wings.

• Panicles become stunted
• Shedding of flowers and immature capsules thus reducing the total number of capsules formed.
• Infestation causes formation of corky encrustations on capsule resulting in their malformed and shriveled condition.
• Such pods lack their fine aroma and the seeds within are also poorly developed.

• Parasitoids: Aphidius colemani, Aphelinus spp.
• Predators: Lacewing, ladybird beetle, spider, syrphid larva.

Hairy caterpillar

• Egg: 300 – 800 eggs are laid on the under surface of leaves of shade trees. Egg period 13 – 20 days.
• Larva: Larva is hairy and has a dark – grey body, pale brown head. Larva undergoes 10 instars in 5 months.
• Pupa: Pupate in soil at a depth of 2 – 2.5 inch, pupa is cocoon, pupal period 7– 8 months.
• Adult: The adult is a large moth measuring 70 -80 mm, ochrus in colour with post medial lines on the wings.

• The caterpillars congregate on the trunks of shade trees and then descend to the cardamomplants.
• They feed voraciously the leaves of cardamom plants, defoliating within a short time.

White grub

• Eggs: Adult beetles emerge by March-April and lay their eggs in the soil. The eggs are soft, ellipsoid, off-white, and about 1 mm long on the longest axis.
• Grubs: The larvae are fat, whitish or cream coloured grubs, and generally about 38 mm long when fully grown. The newly-hatched grubs emerge during June-August and continue to develop up to October/November. During this period, the feeding grubs are found in the top 6 inches of the soil but may move deeper when the soil is very dry. The larvae feed on plant roots and organic matter in the soil.
• Adults: The adults are typical chafer beetles, mostly brown, and 19-20 mm long.

• Affected plants show yellowing of the foliage, scorching of leaves, defoliation and dieback.
• Inspection of the root system will reveal that the roots have been chewed off leaving calloused stumps. H. disparilis also feeds on the at soil level, causing of the stem followed by death of the plants

• Nematode: Heterorabditis nematode.

Root knot nematode

• Most species of plant parasitic nematodes have a relatively simple life cycle consisting of the egg, four larval stages and the adult male and female. They are microscopic in size.
• Development of the first stage larvae occurs within the egg where the first moult occurs. Under suitable environmental conditions, the eggs hatch and new larvae emerge to complete the life cycle within 4 to 8 weeks depending on temperature.
• Nematode development is generally most rapid within an optimal soil temperature range of 70 to 80°F.

• Poor germination of seeds in the primary nurseries.
• Poor establishment after transplanting to secondary nurseries or main field.
• Yellowing and drying of leaf tips and margins
• Stunting and poor growth of the plants.
• Heavy galling and abnormal branching of roots.

• Primary: Egg masses in infected plant debris and soil or collateral and other hosts like Solonaceous, Malvaceous and Leguminaceous plants act as sources of inoculum
• Secondary: Autonomous second stage juveniles that may also be water dispersed

IPM for Large Cardamom

To know the IPM practices for Large Cardamom, click here.

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