Insect and pest of cardamom and their management

 Cardamom is an important cash crop which falls under as spices crop.  Its seed pods have a strong, camphor-like flavor, with a smoky character derived from the method of drying. It is cultivated throughout the world. It is important spice crop but it is attacked by various insects and pest.  As a result the production of cardamom is decreasing day by day . The major insects and pest of cardamom are as follows  : 

- Leaf eating caterpillar ,Clelea plumbeola 

(Lepidoptera: Zygaenidae)

- Banana Aphid, Pentalonia nigronervosa (Hemiptera: Aphididae) 

-Cardamom Thrips, Sciothrips cardamom

(Thysanoptera: Thripidae)

-Cardamom hairy caterpillar, Eupterote sp

Leaf Eating Caterpillr, Clelea plumbeola (Lepidoptera: Zygaenidae) 

The leaf eating caterpillar, Clelea plumbeola is most destructive insect pests of cardamom. It is commonly found in cardamom plantation in Nepal. The larva feed on green matter of the leaves voraciously and defoliate the cardamom plants casuing extensive damage to the cardamom plants ultimately reducing the yield significantly. Only midribs remain uneaten. 

Biology 

• 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. 

Damage symptoms 

• 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. 

Management: 

-Hand picking and Mechanical destruction of caterpillars in early stage of attack. 

-Applying insecticide derived from the soil bacterium Bacillus thuringiensis var. kurstaki is effective on young larvae feeding on plant leaves. 

-Spray 500 ml of malathion 50 EC in 250 litre of water per ha. 

Cardamom Thrips, Sciothrips cardamom

(Thysanoptera: Thripidae)

It is another major insect of cardamom.  They cause damages in leaf and flowers.The adult are highly destructive. 

Biology

• 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.

Damage symptoms 

• 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

Management 

-Remove weed and other hosts that harbor thrips or viruses

-Sprinkler irrigation can help reduce thrips populations

-Entomopathogenic fungi such as Beauveria bassiana and Cordyceps  can be used against one or more life stages

-Azadirachtin can be used as biological insecticide 

-Chemical pesticides like methomyl ,  bifenthrin , lambda-cyhalothrin ,  etc. Can be used .