Coffee White Stem Borer
Xylotrechus quadripes
📖 Description
Coffee White Stem Borer (CWSB) is the most destructive pest of Arabica coffee across the Indian subcontinent, particularly in Karnataka, Kerala, and Tamil Nadu. Adult female beetles lay eggs in bark crevices on the main stem and primary branches. Newly hatched larvae bore into the bark and tunnel extensively through the stem, feeding on the inner bark and sapwood. Tunnels weaken the stem, disrupt water and nutrient transport, and cause yellowing, wilting, dieback, and plant death. The pest’s hidden internal feeding makes chemical control difficult. The most effective management strategy is prevention — adequate shade (50-60%), lime whitewashing of stems to deter oviposition, maintaining plant vigor, and tracing and uprooting infested plants before adult emergence. CWSB has caused abandonment of Arabica coffee in many traditional growing areas of India.
⚠️ Symptoms to watch for
- Yellowing and wilting of leaves, ridges and swellings on the bark, bore holes with frass extrusion, splitting bark exposing larval tunnels, dieback of branches, sudden death of plants in advanced stage, yield loss 30-100%, plant death in 1-2 years of infestation
🩹 Treatment
- Manually extract larvae with a hooked wire, swab stems with Beauveria bassiana paste, spray neem oil on stems, trace and destroy infested plants, swab stems with lime (whitewashing) to deter oviposition
🌿 Organic treatments
- Manually extract larvae with a hooked wire, swab stems with Beauveria bassiana paste, apply Metarhizium anisopliae in stem wounds, swab stems with neem oil 5 ml/L, trace and uproot infested plants before adult emergence, burn infested plant material, swab main stem and primaries with lime (whitewashing) to deter oviposition, mulch and shade to maintain plant vigor
🧪 Chemical treatments
- Swab stems with Chlorpyrifos 20 EC @ 5 ml/L, swab with Monocrotophos 36 SL @ 5 ml + 5 ml water + 90 g clay paste, drench soil around base with Imidacloprid 17.8 SL @ 1 ml/L, spray Lambda-cyhalothrin 5 EC @ 1 ml/L on stems (limited efficacy on internal larvae)
🛡️ Prevention
- Plant Arabica coffee under adequate shade (50-60%), swab main stem and primary branches with lime (whitewashing) twice a year to deter oviposition, maintain plant vigor through proper nutrition and irrigation, trace infested plants monthly and uproot before adult emergence, burn infested plant material, avoid transportation of infested plant material, plant resistant varieties where available, conserve natural enemies by avoiding broad-spectrum insecticides
🪴 Affected plants
- Arabica Coffee (Primary), Occasionally Robusta Coffee
🦋 Natural predators
- Birds (woodpeckers), Predatory Beetles, Ants, Spiders, Entomopathogenic Fungi
🌱 Host plants
- Coffea arabica (primary), Coffea canephora (robusta, rarely)
🔄 Lifecycle
- Female lays 30-100 eggs in bark crevices on the main stem.
- Eggs hatch in 6-10 days.
- Larvae tunnel through the stem for 4-6 months, passing through 6-8 instars.
- Pupation occurs in a pupal cell inside the stem, lasting 15-30 days.
- Adults live 30-60 days.
- Total life cycle 6-9 months; 2 generations per year (adult emergence peaks Apr-May and Sep-Oct).
📅 Season
- Year-round, adult emergence peaks Apr-May and Sep-Oct
🔎 Appearance
- Adults are dark brown to black longhorn beetles with characteristic white markings on the head, thorax, and wing covers.
- Larvae are creamy-white, legless grubs with a brown head, growing up to 25 mm, found tunneling inside coffee stems.
💥 Damage level
- Severe
🔁 Reproduction rate
- Slow
🗺️ Geographic regions
- Indian Subcontinent
- Southeast Asia
- East Asia
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