Insect Pests of Fruit, Plantation, Medicinal & Aromatic Crops (2+1)

1. Thrips - Thrips tabaci Lind. (Thripidae : Thysanoptera)

Damage

• The nymphs and adults which shelter between the leaf sheaths and stems lacerate the epidermis and suck the exuding sap.
  
• The affected leaves exhibit silvery which blotches leading to distortion, wilting and drying from tip down wards.
  
• The seedlings show retarded growth.
  
• The bulbs remain undersized and appear distorted in shape.
Bionomics

• It reproduces parthenogenetically.
  
• The adult female inserts the eggs into the tender leaves.
  
• The egg period is 10-15 days.
  
• The nymphs and adults are yellow in colour.
  
• The nymphal period is 4-6 days.
  
• It pupates in soil. The pupal period is 3 days.
  
• The pest undergoes 10 generation per year.
Management

• Grow resistant varieties viz., White Persian, Grano, Sweet Spanish, and Crystal wax.
• Use neem coated urea which reduce the infestation of pest.
• Set up sky-blue colour sticky traps which attract more adults than yellow colour traps.
• Spray methyl demeton or dimethoate at 1 ml/litre or monocrotophos 1 ml/litre with teepol 0.5 ml/litre of water.