Plant {Sanitation* 



86 



some offensive properties to other insects and is certainly a protective device. 

 When ejected on to the human skin it produces a reddish brown stain that defies 

 soap and water for many days. I would suggest the following additions to 

 Mr. Stebbing's ' points requiring further observations and elucidations.' 



(a) What proportion of the nests contain accumulations of rubber ? 



(b) What is the condition of such rubber ? Does it appear to have coagu 

 lated in mass (such as would occur from a natural flow), or to have 

 been built up— bit by bit, — as would be expected if resulting from the 

 individual collections of numerous insects ? 



(c) Does the milky fluid found in the bodies of the insects have the same 

 reaction as true rubber ? 



Mycological Notes. 



By T. Petch, Government Mycologist. 



The fungi hitherto recorded as parasitic on Castilloa elastica are not very 

 numerous, and in most cases are negligible from an economic point of view. The 

 most important is Corticium javanicum, Zimm., which grows on the branches and 

 apparently kills them. It is a common fungus in Java and attacks all kinds of trees, 

 covering the stems and branches with a flesh-coloured or yellow sheet of fungus 

 tissue, and producing the open wounds commonly known as "canker." Up to the 

 present there is no record of its occurrence in Ceylon. 



Other Javanese fungi on Castilloa include Antennaria castilloae, Zimm., which 

 forms a black covering on the leaves attacked by scale insects ; Aschersonia 

 sclerotioides, Henn., which probably is not parasitic on the leaf, but on a scale insect ; 

 and Diplopeltis Zimmermanniuna, Henn., also on leaves. These apparently do prac- 

 tically no damage to the tree. 



With the extension of Castilloa cultivation the number of parasitic fungi 

 will no doubt increase, though it is rather remarkable thac recent accounts of 

 Castilloa plantations, while referring to injurious insects, make no mention of fungi. 

 Already three can be added to the list from Ceylon. 



The first of these is a root fungus which attacks all cultivated plants from 

 Caravonica cotton to Hevea. It covers the root with a brown felt which cements to 

 itself soil and stones and forms a mass sometimes double the original diameter of the 

 root. When far advanced this covering acquires a black, uniform, external layer. 

 It passes from one root to another when they are in contact, but apparently it does 

 not spread through the soil unless there is a continuous path of living or dead wood. 

 Many instances have been recorded of its occurrence on various plants, but in every 

 case the disease seems to have been got rid of by removing the affected tree and 

 liming the soil. The fructification of this fungus has not yet been found or culti- 

 vated; apparently it occurs in other countries on cacao and coffee, etc., and the 

 same difficulty is experienced in determining to what species the mycelium belongs. 



The second fungus is, according to our present knowledge, a wound parasite 

 only. It occurred on the Experiment Station, Peradeniya, where it attacked two 

 trees which had been injured by fires. A strip of bark about three feet long and 

 four inches broad on each tree was converted into a black, soft rotting mass contain- 

 ing fungi and insects of variotis kinds. The most abundant species, and the only one 

 found near the sound bark, was a Botryodiplodia which has been named fiotrj/odi- 

 rtlodia elastica*. The mycelium of this extended into the wood and discoloured it, and 

 the black coloration of the decaying mass was due to the mycelium and f'ructi- 



