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

1. Cashew tree borer

1. Cashew tree borer Plocaederus ferrugineus Linn. (Cerambycidae: Coleoptera)

Damage

• The grubs tunnel and feed inside the tree trunks and branches and damage cambial tissues and stop the flow of sap.
• It results in weakening and death of the plant.





Bionomics

• The adult beetle is reddish brown measuring 25-40 mm in length.
  
• It lays eggs in the cracks and crevices of the loose bark on the trunk.
  
• The eggs are ovoid or elliptical and dirty white in colour hatch in 4-6 days.
  
• The newly hatched grubs start feeding on soft tissues and bore in to the bark and make tunnels.
  
• The grub is off-white colour and the grown up grub measures 60-75 mm in length.
  
• The fully grown grub decends to root zone through tunnels.
  
• The grub stage last for 6-7 months.
  
• The pupal period last 60 days inside the cocoon.
Management

• Uproot and remove the dead trees from the plantation as they serve as source for multiplication of the borer.
• Avoid any injury or damage to the stem and exposed portion of the root.
• Apply coal tar and kerosene (1:2) on the trunk up to 1 metre height which prevent the beetles from egg laying.
• Detect the infestation in the early stage and swab the tree trunk with carbaryl 50 WP 0.1% suspension to save the tree.
• Adopt stem padding with cotton wool soaked in monocrotophos at 30 ml /tree gives good recovery.
• Follow the root feeding of monocrotophos 36 WSC 10 ml +10 ml of water kept in a polythene bag in two places (20 ml / tree) gives good protection to the trees.