DANGEROUS FOREST DISEASES IN INDIA 



B. K. Bakshi 



Head, Division of Forest Protection, Forest Research Institute, New 

 Forest (Dehra Dim), India 



Spike Disease of Sandal 



Virus (No specific name). A serious virus disease of sandal 

 (Santalum album L.) in south India. The symptoms first appear in 

 one or more branches, in which new leaves become progressively re- 

 duced in size, pale and stand stiff and crowded on shortened internodes, 

 giving a spikelike appearance. Spike eventually spreads over the 

 entire tree which exhibits continuous growth. In advanced stages of 

 disease, flowers and fruits do not develop. If a branch is spiked after 

 inflorescence is formed, fruits become reduced in size, or flowers exhibit 

 phyllody. Haustoria and fine root ends die. In spiked branches and 

 leaves, starch is significantly more, while nitrogen and ash less than in 

 normal leaves. The spiked tree never recovers and dies in a few years. 



Disease is transmitted by grafting and not communicable by sap 

 transmission. Intracellular cell inclusions are demonstrated. The 

 claim that Jassus indicu-s is a vector for the disease is not confirmed 

 and any other insect is yet unknown. Several plants show symptoms 

 of spike and some of them serve as hosts for sandal. 



Eradication of diseased trees or lopping spiked branches does not 

 reduce incidence of disease. Marking out susceptible and resistant 

 hosts, and propagating sandal on the latter is suggested. However, 

 some principal susceptible hosts like Lantana camara. are excellent 

 nurse crops for sandal and their eradication is practicable. Natural 

 selection of x^esistaixt trees and propagating them through seeds has not 

 controlled the disease. In nature, sandal grows healthy, free from 

 spike under shade. Control of spike may be attempted by raising 

 sandal under a light canopy of trees to serve as good sandal hosts and 

 at the same time afford some degree of resistance to spike. 



The disease has killed sandal in large tracts in south India. It 

 spreads in the direction of wind. Although sandal is now naturalized 

 in India, it is suggested that it was introduced from Java in the remote 

 past. The disease may have occurred naturally on some native plants, 

 where it is harmless, and from which it transferred to sandal, finding 

 the exotic highly susceptible. 



The disease is known only in India. Not reported from Malaysian 

 islands and Australia where sandal occurs naturally. Export of living 

 sandal from India except seeds for experiment should be forbidden. 

 Hosts: Santalaceae — Santalum album L. 



Literature: Coleman. L. C. Spike disease of sandal. Mvcol. Ser., 

 Bui. 3, Dept, Agr., Mysore State. 1917. 



Deodar Witches'-Broom 



Peridermiwm cedri (Barclay) Sacc. A needle rust of deodar 

 (Cedrus deodara Loudon). Attacks young needles of the current 



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