Mango stem borer

Systematic position: The mango stem borer (Batocera rufomaculata) is a member of the order Coleoptera and the family Cerambycidae. It is a highly destructive wood-boring beetle known for its significant impact on various tree species, acting as a major pest in both fruit orchards and forest plantations.

Host plants: This insect is a significant polyphagous pest with a very wide host range. It infests various economically important trees, most notably mango, fig, mulberry, rubber, pomegranate, and several fruit-bearing species like apple, pear, and citrus. Its ability to thrive on diverse hosts makes it a high-risk pest in tropical and subtropical regions.

Biology and life cycle: The life cycle progresses through the egg, larva, pupa, and adult stages. Adult beetles are primarily nocturnal, feeding on the bark of tender shoots. Females lay eggs in crevices of the bark or into intentionally gnawed wounds on the tree trunk or thick branches. Once hatched, larvae tunnel into the bark and eventually penetrate deep into the woody xylem tissues.

Nature of damage and pest status: The damage is caused by the larval stage, which feeds internally within the woody tissue. This burrowing activity disrupts the vascular system (xylem and phloem), preventing the flow of nutrients and water. Typical signs of infestation include the presence of circular exit holes, decaying sap, and frass or wood shavings extruding from the entry points, which often leads to tree decline and eventual mortality.

Control measures: Management of Batocera rufomaculata is challenging due to the concealed nature of the larvae:

• Implementation of strict quarantine and phytosanitary measures for plant material.
• Pruning and destroying heavily infested branches or whole trees to reduce population density.
• Applying systemic insecticides or contact treatments on trunks during adult emergence periods.
• Injection of chemical formulations directly into the larval holes.
• Encouraging natural biological control agents and regular monitoring of orchards.