Title : Sandalwood spike disease diagnosis and control
Abstract:
Sandalwood is the important bio-resource of India and the second most costly wood in the world is now in the IUCN Red list of threatened species. Its cultivation outside forest areas are expected to give best return to the farming community and enhance of trade of sandalwood and its products. But the resurgence of deadly Sandalwood Spike Disease (SSD) has put these plans under hold. Although SSD is more prominent in natural populations slowly found transmitting to farmers field due to the vertical transmission resulting in the death of plants due to SSDs association with Candidatus Phytoplasma asteris. In the study we perceived morphological characteristics viz., chlorosis, reduction in leaf-size, and shortened internodes, causing leaves to become crowded on twigs with a ‘bushy’ appearance and stems standout stiffly with spike-like appearance. Which was further confirmed using phytoplasma specific PCR assay. Many sap-sucking (planthoppers and leafhoppers) insects suspected as vectors were collected, identified and confirmed which was vital for containment and management of spread of the disease. To control SSD spread we evaluate the non-chemical methods including entamopathogenic fungi found in field mummifying putative vectors of SSD. The incidence of SSD ranged from 0 to 14 per cent in symptomatic trees and 0 to 6.33 per cent in dead sandal trees. total 1546 leafhopper specimens were collected from different spike areas representing 104 species of which 35% were found phytoplasma positive in DNA barcoding. Efficiency of the entomopathogens isolated from potent vectors in controlled laboratory trials showed promising result.
Keywords: Sandalwood Spike Disease, Phytoplasma, DNA barcoding, Entamopathogenic fungi, Control
