Sandal Spike Disease Vector

📖 Description

Sandal Spike Disease, transmitted by the leafhopper Hishimonus phycitis, is the single most destructive disease of Indian sandalwood (Santalum album) — a tree species of immense cultural, religious, and economic importance in India. Indian sandalwood is the world’s most valuable wood, fetching ₹6,000–12,000 per kg of heartwood; the Mysore sandalwood oil (essential oil distilled from heartwood) is a Geographical Indication (GI) tagged product that supplies the global premium perfumery and incense industry. Historically, the sandalwood trade was a state monopoly of the Kingdom of Mysore (and later Karnataka and Tamil Nadu governments), generating significant revenue and supporting an estimated 50,000 rural families engaged in sandalwood carving (the famed Mysore sandalwood carvings). Sandal Spike Disease was first reported in 1899 from Coorg (Kodagu) in Karnataka, and has since destroyed an estimated 1.5 million sandalwood trees across the forests of Karnataka, Tamil Nadu, and Kerala — reducing India’s standing sandalwood stock by ~70 % over the past 120 years. The disease is caused by a phytoplasma — a cell-wall-less bacterium related to the genus Acholeplasma — that lives exclusively in the phloem sieve tubes of infected plants. Because phytoplasmas cannot be cultured in artificial media, no cure exists, and management depends entirely on preventing spread by controlling the leafhopper vector. Hishimonus phycitis is the proven vector — the leafhopper acquires the phytoplasma by feeding on infected sandalwood (or other phytoplasma reservoirs) and transmits it to healthy trees during subsequent feeding. The disease is inevitably lethal within 6–24 months of symptom appearance. The Institute of Wood Science and Technology (IWST, Bangalore) maintains India’s national Sandalwood Pest Surveillance Network and has developed the current integrated management protocol that combines roguing, vector control, and mixed-species planting.