1921.'] SUGAR CANPJ PESTS AMD DISEASES. 115 



seen, m one case as many as twenty on one stool. The infection was at 

 its height about December 1, but reduced rapidly with drier weather 

 from this date and by December 10 there were not one-tenth as many 

 infected specimens to be found. 



Eighty-three infected specimens collected at -random in the field on 

 December 3 showed that fifty-eight were males and twenty-two females. 

 This excess of males is exactly opposite to what is found in the green 

 muscardine fungus which always infects a larger proportion of fennles. 



THE MOSAIC DISEASE. 



. History and Present Situation. 



,\t the time of the discovery of the Mosaic Disease in Trinidad, at 

 the beginning of 1920, it was found to be confined to(l) an area of 

 uncertain uxtent, mostly in farmers' canes, surrounding the Government 

 Experiment Station at St. Augustine, where the disease had been 

 distributed partly by natural spread, partly by sale of plants and partly 

 by theft of diseased cuttings from the Station; and (2) about forty 

 isolated localities throughout the country where diseased cuttings had 

 been sent from the Station. The evidence then available indicated St. 

 Augustine as the point of introduction of tlie disease and the only centre 

 of infection. 



Since then one estate has been found to be heavily infested bith in 

 nursery plants and old ratoons indicating that the disease has been 

 present several years at least. On this estate the infection is more 

 severe and widespread tlian at the Government Station and it is possible 

 that it represents a second point of introduction. Seedling canes have 

 been introduced into Trinidad by this estate for man}' years past but, 

 iis far as is known, onl^' from Barbados, and the discovery of the disease 

 in that island is so recent and localised that it seems improbable that 

 it has been present there for more than a year or two. 



Control work was started as soon as the disease was identified, bub 

 during the dry season of 1920, which was an excellent opportunity for 

 destruction, the seriousness of the disease liad not been realised by 

 most ])eople concerned. Owing to the apathetic attitude of most of the 

 planters and the small staff available for the work very little was done 

 before the wet season. 



About a month after the wet season started the disease began to 

 spread with considerable rapidity, particularly in the Northern Sugar 

 district among small farmers' canes, and even with an increased number 

 of raencvitting out and destroying it was soon quite out of hand. The area, 

 infested was found to be larger than was at first suspected and no field 

 ■could be visited frequently enough to prevent renewed infection from 

 occurring, often greater than the infection originally found. 



In the Naparimas and Couva districts, where most of the points of 

 infection were in large estates, the situation did not become so bad, as 

 vhen the nature of the disease was realised, greater and more frequent 

 el'forts were made to eradicate it. As a result nearly all the points oi: 

 infection in the Naparimas have been greatly reduced. Four or live 

 have been completely cleared and the remainder have been reduced from 

 -an average of about 100 diseased stools per inspection to less than 10, 



