Mango Stem Borer
Batocera rufomaculata
📖 Description
Mango Stem Borer is the most destructive pest of mango orchards in the Indian subcontinent, particularly severe in old, neglected orchards across Uttar Pradesh, Bihar, Andhra Pradesh, Maharashtra, Karnataka and Tamil Nadu. The grub tunnels deep into the main trunk and large branches, weakening the tree structurally and causing branch snapping and eventual tree death. Once a tree is infested, saving it is extremely difficult — the pest is often only noticed when branches snap or trees suddenly decline. Prevention through trunk swabbing with insecticide paste, avoidance of injuries, and removal of infested trees is essential. The pest has a long life cycle (1-2 years) and adults emerge in waves, making monitoring difficult. Entomopathogenic fungi and nematodes are emerging as organic alternatives to chemical hole injections.
⚠️ Symptoms to watch for
- Bore holes on trunk and main branches with extrusion of wood powder and frass, yellowing and wilting of canopy, branch die-back, gum exudation, sudden snapping of branches or toppling of tree, complete tree death in 12-24 months
🩹 Treatment
- Locate bore holes, insert hooked wire to kill grubs, plug holes with Carbaryl paste (1:1 with water), apply Chlorpyriphos @ 2 ml/L as trunk swab, prune and burn infested branches, fell and burn severely infested trees
🌿 Organic treatments
- Locate and kill grubs with hooked wire, apply Metarhizium anisopliae paste (50 g/L) into bore holes, plug with Beauveria bassiana + clay paste, entomopathogenic nematodes (Steinernema, Heterorhabditis) @ 1 million/hole through cotton swab, neem oil 5% paste on trunk
🧪 Chemical treatments
- Carbaryl 50 WP paste @ 50 g/L (plug bore holes), Chlorpyriphos 20 EC @ 2 ml/L (trunk swab), Monocrotophos 36 SL @ 1 ml/L (inject into bore hole and plug with clay), Dichlorvos 76 EC @ 1 ml/L (hole injection)
🛡️ Prevention
- Avoid bark injuries during pruning and cultivation, swab main trunk and primary branches with Carbaryl paste twice yearly (Mar-Apr and Oct-Nov), maintain proper nutrition and irrigation, prune infested branches and burn, remove and burn dead trees before adult emergence, plant at proper spacing to avoid stress
🪴 Affected plants
- Mango, Cashew, Jackfruit, Fig, Mulberry, Rubber (occasionally)
🦋 Natural predators
- Woodpeckers, Predatory Ants, Carabid Beetles, Entomopathogenic Fungi, Spiders
🌱 Host plants
- Mangifera indica, Anacardium occidentale, Artocarpus heterophyllus, Ficus carica
🔄 Lifecycle
- Female lays 200-400 eggs in bark crevices on trunk and main branches.
- Eggs hatch in 7-14 days.
- Grubs tunnel inside wood for 12-24 months through 5-6 instars.
- Pupation inside cocoon in tunnel, lasting 25-40 days.
- Adult lifespan 60-120 days.
- Total life cycle 18-30 months; 1 generation per 2 years.
📅 Season
- Adult emergence peaks Mar-Jun and Sep-Nov
🔎 Appearance
- Adult is a large greyish-brown longicorn beetle with two prominent reddish-brown spots near the wing bases and yellowish-white stripes on antennae.
- Grubs are large, creamy-white, cylindrical with a brown head.
- Pupae are pale yellow inside a cocoon of wood fibers in the tunnel.
💥 Damage level
- Severe
🔁 Reproduction rate
- Slow
🗺️ Geographic regions
- Indian Subcontinent
- South Asia
- Southeast Asia
- China
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