What are the pests that could harm cardamom and how to deal with them?

1. Cardamom thrips (Sciothrips cardamomi)

    Cardamom thrips are the most destructive and persistent pest of cardamom, found in almost all the cardamom growing areas. Thrips breed inside the unopened leaf spindles, leaf sheaths, flower bracts, and flower tubes. Adults, as well as the larvae, lacerate and feed on leaves, shoots, inflorescences, and capsules. Infestation on the panicles results in the shedding of flowers and immature capsules. Feeding activity on tender capsules leads to the formation of corky, scab-like encrustations. The extent of the damage may be as high as 80 percent in certain areas. The population of thrips is generally high during the summer months (February- May) and declines with the onset of monsoon. The Mysore and Vazhukka types are highly susceptible to thrip infestation.

      Management

• Regulate shade in the plantation by pruning branches of shade trees.
• Trash cardamom plants thrice a year i.e., during early monsoon, mid-monsoon, and late monsoon periods to remove breeding sites of the pests
• Spray insecticides like quinalphos (0.025%), during March, April, May, August, and September.

2. Shoot and capsule borer (Conogethes punctiferalis)

    The shoot and capsule borer is a serious pest in nurseries as well as in the main plantations. The larvae bore into pseudostems and feed on the internal contents leading to the formation of 'dead heart' symptoms. When panicles are attacked, the portion ahead of the point of entry dries off. The larvae also bore into the capsules and feed on the seeds resulting in empty capsules. The pest is prevalent throughout the year but a higher incidence is pronounced during the months of January-February, May-June, and September-October.

     Management

• Remove infested suckers as indicated by extrusion of frass, during September-October when the infestation is less than 10%.
• Collect and destroy adults which are generally observed on the undersurface of leaves.
• Spray quinalphos (0.075%) twice, during February-March and September-October coinciding with the emergence of panicles and new shoots.

3. Root grub (Basilepta fulvicorne)

    Root grubs are major pests of cardamom in nurseries and main fields. The grubs damage the roots and rhizomes by feeding, sometimes resulting in the death of the entire root system. As a result, the plants turn yellow and remain stunted; severely infected plants die. The peak periods of adult emergence are during April and September. Grubs have two periods of occurrence, first during April-July and January.

      Management

• Collect and destroy adult beetles during peak periods of emergence i.e. April-May and September – October
• Apply phorate 10 G (banned in Kerala) @ 20–40 G per clump or chlorpyrifos (0.075%) twice a year during May−June and August-September synchronizing with the emergence of adults and egg-laying periods of the pest.
• Light raking of the soil before the insecticide application is essential for effective control of root grubs

Source: Vikaspedia: Cardamom