W. MCRAE 261 



ejiperienced on the rubber estates. With the almost continuous rain the 

 opportiuiity of continuous distribution by splashing is given, and even though 

 frequent collisions between splash-drops and rain-drops will occur, thus 

 preventing many of the former from reaching their extreme distance, still 

 some of them will be carried off, and be again splashed farther distances. This 

 explanation would seem to be sufficient to accoimt for the rapid spread of the 

 fungus from fi-uit to fruit and to leaves on an estate, and the great numbers 

 produced on infected fruits provide many opportunities of their being washed 

 down on the tapping surface. 



Loss. 



]Hevea has been attacked by this fungus in South India before planting 

 has been well established, so that there is no very extensive series of fi"-ures 

 showing the yield of latex for any length of time on the estates of healthy 

 trees. Estates have been in bearing for only a few years, 8 or 10 at the most, 

 and that on a comparatively small acreage which has gradually become affected 

 by abnormal leaf -fall. It is thus difficult to estimate the latex yields that 

 might normally be expected. That so far they have not come up to the expec- 

 tation current at the time of planting is fairly generally conceded, and part of 

 the shortage is undoubtedly due to the effects on the trees of PhytopJithora. 

 The loss due to the rotting of fruits is a minor factor, as the utiHzation of fruits 

 for purposes other than planting, for the present at any rate, hardly comes 

 into the estimate. From discussions with most of the planters who have had 

 much to do with the disease, I have come to the conclusion that 30 to 40 lbs. 

 of made rubber per acre per annum is about the average loss, and it may be as 

 high as 70 or 80 on badly infected blocks of trees. This transposed into money 

 value, with the rubber, say, at 2/9 per pound and the cost of production, say, 

 at 9 pence a pomid, gives a loss of from £3 to £4 per acre per annum which 

 multiplied by the yielding infected area of about 30,000 acres represents a 

 total loss to the industry of about £100,000 sterUng and a possible futm-e loss 

 over the area of 60,000 acres of a very large sum of money indeed. The loss 

 involved is so large that it is practicable to spend a large sum of money on 

 remedial or preventive measures on every estate. 



Preventive measures. 



It is only recently that the Ufe-history of the fmigus has been worked 

 out in comparative detail so that the discussion of combative measures 

 against it ia more a suggestion of Unes of work than a statement of definite 

 means of prevention. In this comiection the main facts to be borne 

 in mind are (1) that the myceUum passes the diy-weather inside branches that 



