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

3. Stem borer Bark borer

3. Stem borer Bark borer - Batocera rufomaculata Dejean. (Cerambycidae: Coleoptera)

Damage

• The grubs feed by tunneling through the bark of branches and main stem.
  
• The damage may also show itself by the shedding of leaves and drying of terminal shoots in early stage of attack.
  
• When the damage occurs at the main stem, the whole tree succumbs.
Bionomics

• The adult is a large longicorn beetle about 5 cm long and 1.6 cm broad and yellowish brown in colour.
• It has two pink dots and lateral spines on thorax. It lays eggs singly on the bark, or cracks and crevices on the tree trunk or branches hatch in about 1-2 weeks.
• The grub is stout with well-defined segmentation and yellow in colour.
• The grub makes zig - zag burrow beneath the bark.
• The grub feeds on the internal tissues and become full fed in about six months.
• It pupates inside the tunnel itself.
• The pupal period is. 19-36 days.
Management

• Remove and destroy the dead trees and affected branches from the garden.
• Swab trunk with carbaryl 20 g/1.
• Use light trap 1 / ha to attract adult moths or beetles.
• Locate bore holes, spike out grubs using a needle or iron wire.
• Exclude the alternative host, silk cotton from mango orchards.
• Grow less susceptible varieties viz., Neelam, Humayudin, and Panchavarnam.
• Swab coal tar + Kerosene (1 :2) on the basal part of the trunk up to 3 feet high after scraping the loose bark to prevent the female from egg laying.
• Spike out the grub if the bore holes are located, and add insecticide emulsion (monocrotophos 0.1 % at 20 ml / hole) a fumigant tablets (3 g aluminium phosphide) or petrol and seal the holes with the mud.
• Follow padding with monocrotophos 36 WSC 10 ml per tree soaked in absorbent cotton when the trees are not in bearing stage.
• Apply carbofurean 3 - 5 g per hole and plug with mud after removing the grub by using needle.
• Apply carbofuran granules in the soil at 75 g / tree basin.