Spike disease grips Marayoor sandalwood trees, COVID-like containment measures in place

Kozhikode: An outbreak of spike disease in sandalwood trees has forced the Kerala forest department officials to adopt COVID-like preventive tactics in the Marayoor forests of Devikulam taluk in Idukki district of Kerala.

The Kerala Forest Research Institute (KFRI) and Coimbatore-based Institute of Forest Genetics and Tree Breeding (IFGTB) have jointly developed PCR test-like kits to identify the infected trees.

Sandalwood trees would be undergoing PCR tests like in the case of COVID-19. Earlier, the testing kits did not have many takers.

The plan is to root out the infected trees to protect the healthy ones. Marayoor is the only place in Kerala with a natural growth of sandalwood trees.

Currently, there are no preventive mechanisms or cures to check the spread of the communicable disease. Hence, the decision was made to root out the infected trees, Forest Minister A K Saseendran said.

Infected trees that could be sold would be shifted to the department's depot. The minister added that the infection would not be allowed as an excuse for the extensive axing of the royal trees.

According to estimates, as many as 2,000 trees have been infected with the disease, which would translate to the loss of forest produce worth Rs 160 crore.

The disease

The sandalwood spike disease has infected about 2,000 trees behind the Forest Range Office at Marayoor. Caused by phytoplasma — bacterial parasites of plant tissues — the vector-borne disease is also transmitted plant-to-plant.

The leaves of the infected trees shrink and become thorn-like in two years. The branches also shrink, and the tree would eventually dry up and die.

Currently, four research institutes of the Indian Council of Forestry Research and Education (ICFRE) and KFRI are jointly involved in research activities to find a cure. Dr Madhumita Das of the IFGTB is coordinating the studies.

The sandalwood trees at Mannarkkad, Periyar, Thenmala and Chalakudy divisions are free of the bacterial disease. A team led by Dr Suma Arundev of the Forest Genetics and Biotechnology wing of the KFRI and research fellow Reshma Baskar has been taking care of the trees in these divisions.

Dr Suma Arundev said enough samples could be tested if the forest department demands.

Sought-after asset

Marayoor has 57,000 sandalwood trees, and to overcome the annual decrease of 1,000-3,000 trees, about 5,000 saplings are planted every year. The most expensive tree from Marayoor could fetch about Rs 5 crore.

The sandalwood trees in Marayoor are of much demand due to their high oil content. While three kilograms of oil could be extracted from 100 kg of sandalwood grown in Karnataka, those in Marayoor could produce six to eight kilograms. Quality sandalwood would cost Rs 16,000 per kilogram.