156 Ustulina Zuiiata (Lev.) Sace. on Hevea Brasilieiisis 



this disease from that caused by Fomes Ugnosus, while the black, rhizo- 

 raorphic strands between the bark and wood of trees attacked by 

 Sphaerostilhe repens serve to distinguish those affected by this fungus. 

 The typical dry-rot in the collar caused by Ustulina zonata cannot be 

 mistaken, the wood in advanced cases falling to pieces under the pressure 

 of the fingers. 



This root disease is common on most of the older plantations in the 

 F. M. S. though its presence is unsuspected. The fungus works slowly and 

 insidiously, the crown of leaves becoming thin as it progresses in the 

 collar. The diseased tissue is usually confined to one side of the collar, 

 and from this side latex cannot be obtained. The opposite side may give 

 a good yield and tapping is continued till the amount of latex obtained 

 begins to diminish. When this stage is reached the tree soon dies and has 

 to be taken out. 



The dry collar-rot has been found occasionally on trees 5-8 years old, 

 but it is only typically developed on trees over 10 years of age. A large 

 number of magnificent trees in the older properties have been killed by 

 this fungus. Cases are quoted later where large areas have been rendered 

 useless owing to attacks by Ustulina zonata and other root fungi. 



Fructifications are found on diseased roots, usually near soil level. 

 They are closely adpressed to the stem; when young the flat plate-like 

 fructifications are soft, rather leathery, whitish in colour and greenish- 

 white at the edges. Later they darken and become brittle and closely 

 resemble exuded patches of coagulated latex attached to the stem, which 

 have blackened owing to exposure and oxidation. In this condition they 

 are easily overlooked. When the fructifications develop near gromid 

 level, they are often difficult to detect as they become splashed with mud 

 after a showier of rain. 



OBSERVATIONS IN FIELD ON RELATION BETWEEN SHOT-HOLE 

 BORER {XYLEB0RV8 PARVULUS) AND USTULINA ZONATA. 



In the report of the Director of Agriculture, F. M. S. for 1914, 

 H, C. Pratt, Government Entomologist, writes: 



" Xyleborus parvulus. This beetle was first noticed in this countr}^ as 

 attacking rubber in 1909. It occurred only in one district. The instance 

 was undoubtedly due to the pollarding of a large number of trees. Many 

 of these pollarded trees were attacked, and in a few cases adjacent trees 

 which had not been pollarded were bored. Since that time this district 

 has always lost a few trees each year from what would appear to be the 

 attacks of this insect. During 1914 there was a remarkable increase in 



