246 



application of quicklime does much to loosen the soil and has also 

 marked fungicidal properties. As much as one or one-and-a-haU 

 tons to an acre may well be applied. 



The fungicidal properties of good quicklime are well-known, but 

 there is much difficulty in obtaining good quicklime in many places, 

 and the material which is sent out by business houses is frequently 

 completely slaked. Attempts are being made to introduce a powerful 

 fungicide which is applicable to a large area of soil. An experiment 

 was conducted with carbon bisulphide, the object being to kill the 

 mycelium which was present in the soil by the vapour of the liquid. > 

 For this purpose a badly infected area of one half of an acre was 

 selected and injected on 26th September with carbon bisulphide by 

 means of a Vermorel's " Pal Excelsior " injector, the injections being 

 three feet apart and, hence, about 4,000 to an acre. An examination at 

 the end of five weeks showed that the fungus mycelium was just as 

 abundant as before. The failure of the vapour to kill of the mycelium 

 was attributed to the rapid vapourisation of the liquid at the tem- 

 perature of the soil and to the small diffusion of the vapour in damp 

 soils. A formaldehyde compound, which has recently been put on 

 the market and which appears to have met with some success, will 

 shortly be experimented with as on a large a scale as possible. It 

 must, however, be borne in mind that the application of such a 

 fungicide is only regarded as being necessary where the land is 

 lowlying and almost swampy, and where, as the result of scarcity 

 of capital or labour, of the absence of removal of timber or of the 

 previous cultivation of another crop which harboured the fungus, 

 or of the absence of good methods drainage and of treatment of 

 isolated cases of disease from the outset, the fungus mycelium is 

 widespread through the soil. Its application is, therefore, secondary 

 to the establishment of got d methods of cultivation. 



The work on the life-history f)f the fungus and on such factors 

 as the spread of the disease and its method of treatment is in pro- 

 gress and will be published in a separate Bulletin of the department. 



Hymenochaete noxia, Berk., appears to be present in this country 

 only in small quantity. The fungus is said to be the commonest 

 root fungus of Hevea in Ceylon. Essentially a jungle product, it 

 was recorded in Samoa as early as 1875, and it is now known to be 

 somewhat widely distributed through the Eastern tropics. Both in 

 this country and in Ceylon there appears to be some considerable 

 difficulty in obtaining fruiting specimens, while in Samoa, and on 

 material which I have examined from West Africa, the fungus 

 appears to fruit abundantly. The disease is known as the " brown 

 root " disease, and, in spite of the absence of fructifications, it is 

 easily identified by the presence of fawn-coloured strands on the roots 

 when the mycelium is young and by the production of dark-browii 

 or almost black sheets of older mycelium which aggregate earth and 

 small stones into masses on the surface of the roots ; it is more 

 specially observable on the tap root. The fungus spreads very 



