Insect Pests of Vegetable, Ornamental and Spice Crops (2+1)

Banana aphid

1. Banana aphid, Pentalonia nigronervosa (Aphididae: Hemiptera)

• Distribution: India, Sri Lanka and Australia.
• Host range: Banana, small and large cardamom, Colocasia sp and Allocasia sp

Damage:

• Both nymphs and adults suck the cell sap from leaf sheath and pseudo stem
• Vector of cardamom mosaic (Kattle disease), Amomum mosaic and foorky disease of large cardamom

Identification

• Wingless aphid is dark brown, pyriporm, 1.34 mm in length.
• Abdomen is dark brown, shining and slightly bulged.
• The winged form is dark brown elongated and pyriform
• They are larger than the wingless with less body width.

Life cycle

• The reproduction is parthenogenetic
• Adult longevity varies from 8-26 days with an average of 14 days
• Each female can lay 8-28 off springs with an average of 14 per female
• Nymphs become mature in 12-15 days
• Four nymphal stages.
• Several overlapping generations in a year

Management:

• Spray 300 ml of phosphamidon 85 WSC or 875 ml of dimethoate 30 EC in 250 L of water per hectare at an interval of two weeks

2. Cardamom thrips, Sciothrips cardamom (Thripidae: Thysanoptera)

• Distribution: All cardamom growing areas
• Hosts: Cardamom

Damage

• Nymphs and adults are damaging
• Lacerates all aerial parts and feed on oozing sap
• Infestation on panicle and flower buds results in stunted growth of panicles, shedding of flower buds and warty growth
• The infested capsules are light in weight, inferior in quality
• Low market price
• This insect is a serious pest of cardamom
• Pest population is high during dry months i.e. December in April.

Management:

• Spraying of quinalphos (0.03%) or phenthoate (0.03%) or phosalone (0.05%) or fenitrothion (0.05%) or dimethoate (0.05%)
• Application of insecticides can be skipped during June-July

3. Cardamom whitefly, Dialeurodes cardamom (Aleyrodidae: Hemiptera)

• Hosts: Cardamom

Damage

• This whitefly is serious on cardamom plants.
• Damage is caused by the nymphs and adults by sucking the cell sap from leaves
• Infested leaves turn yellow
• Attack first appear on the lower leaves and gradually progresses to the upper region
• Severe damage leads to drying up of plants.

Identification

• The eggs are oval shaped
• Nymphs are green in colour

Life cycle

• Each female lays 200-250 eggs
• Eggs hatch in 10-15 days
• Nymphs become pupa in 3-4 weeks
• Pass through 3-4 instars

Salient features

• Lay eggs mostly on the under surface of the leaf.
• Newly emerged nymphs crawl for few hours and after finding a suitable place settle down.
• There are two different seasonal activities i.e. April-May and October-November.
• However, the availability of pest in other seasons can not be ruled out.

Management

• Use of yellow sticky traps
• Need based use of systemic insecticides