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

1. Apple root borer

1. Apple root borer - Dorysthenus hiigelii Redt.(Cerambycidae: Coleoptera)

Damage

• The grub borers into the roots or girdles around the roots and feed on the internal tissues.
• It resulted in shaking of plants, withering and drying of branches.
Bionomics

• The adult beetle is chestnut -red in colour with head and thorax darker than elytra.
• It lays oval shaped yellow white eggs below the soil.
• A female can lay up to 200 eggs. The egg period is 30-40 days.
• The newly hatched out grub goes down to the soil, 100-250 mm deep and feed on the roots of the tree.
• The full grown grub is creamy-white with black head and mandibles measuring 75-100 mm in length.
• The larval duration extends up to 3 % years and it can live without food for 24 - 90 days.
• It pupates in earthern cocoon inside the soil. Its pupal period is about 3 months.
Management

• Avoid dry sandy soils for planting apple orchards