154 Ustuliiia Zonata (Lev.) Sacc. on Hevea Brasiliensis 



This money was never awarded. Experience taught that " Fomes " attacks, 

 even in the worst affected places where it may cause heavy losses, could 

 be treated, and that attacks by White ants created little material differ- 

 ence in the long run on the majority of plantations. After these scares, 

 a period of indifference to rubber pests and diseases set in until 1912, 

 when the rapidity of spread of "Pink disease" throughout the peninsula 

 stimulated enquiry into the necessity for vigorous treatment. The work 

 of Rant (7) and Brooks and Sharpies (2) proved the incidence of the disease 

 and the probable causes of spread, and vigorous preventive measures 

 based upon the work mentioned showed that "Pink disease" could 

 be controlled by concerted effort. Since this time, a large number of 

 plantations have passed the ten years stage and many of the old trees 

 have been killed by fungi attacking the roots. The symptoms have been 

 classed under various headings by Malayan planters i.e. " Wet-feet," 

 "Brown-root disease," "Dry-rot," etc. As a result of work carried out 

 over the last two years these general terms can now be assigned to 

 specific fungi. This contribution deals with the dry collar-rot on old 

 rubber caused by Ustulina zonata (Lev.) Sacc. 



HISTORY OF DRY COLLAR-ROT. 



Brooks (1) in 1915 made the first important contribution to our know- 

 ledge on the subject of U. zonata as a fungus causing a root disease of 

 plantation rubber. Previous to this, Massee(3) in 1910 published photo- 

 graphs and a description of a fungus, Eiitypa caulivora (Mass.) growing 

 on a dead tree of Hevea brasiliensis, taken from the Singapore Botanic 

 Garden by Mr H. N. Ridley. The photograph of the diseased wood shows 

 the typical symptoms of a tree attacked by Ustulina zonata. It is prob- 

 able this fungus was responsible for the death of the tree, E. caulivora 

 growing as a saprophyte on the dead tissue. Numerous saprophytic fungi 

 are always to be found on trees killed by U. zonata which are in an 

 advanced state of decay. Petch(4) in 1910 records a case of U. zonata 

 growing on an old Hevea which had died of root disease, and states that 

 " apparently the disease was caused by this fungus, though the evidence 

 was rather doubtful." Later in 1914 he says (5) " This fungus is a common 

 cause of root disease {i.e. of Tea) in Ceylon, though not on Hevea." He 

 records several cases of U. zonata on Hevea brasiliensis in fields where the 

 trees have been planted among tea which has subsecjuently been allowed 

 to die out. In 1916 Reeves (8), the Mycologist to the Rubber Growers' 

 Association in Ceylon, published some observations on U. zonata with 

 reference to rubber trees, and found the disease common in Ceylon. 



