56 TBINIDAD AND TOBAGO BULLETIN. [XVIIL 3. 



I hoi^e to show in a later report on the relation between blight and 

 rainfall, that the most serious outbreaks of blight have occurred in 

 years when the canes first damaged by the association of Froghopper 

 and root fungi have been further held back by drought at the time of 

 the year when they might otherwise have recovered. 



PEACTICAL APPLICATION. 



The diseases due to root fungi are well known throughout the world, 

 and have been found to lend themselves to treatment the main aspects 

 of which are outlined in Mr. Nowell's report, with whose suggestions 

 I thoroughly agree. 



In those cases in which the Froghopper is believed to be responsible 

 for the beginning of the outbreak, it can be argued that the best control 

 would be to destroy the insect itself and so prevent the evil starting. 

 This is undoubtedly true, but after ten years work we are still without 

 any certain and direct means of destroying the Froghopper. There is no 

 knowing at what time some such niethod may be discovered, but until 

 then much can be done by reducing the amount of root fungus present, 

 so that the Frogliopper may have no powerful ally to help him in his 

 destruction and to carry on liis work after he is gone. 



If one field will give a reasonable cro]:) with thirty Froghippers per 

 stool, there is no reason why ten Froghoppers per stool in another field 

 should be allowed to destroy h. 



It is not too much to say tliat fifty per cent, of the damage at 

 present caused by blight could be prevented without any alteration in 

 the number of froghoppers. 



There will still remain the outbreaks in which the damage is due 

 entirely to the abnormal numbers of insects present, and for the prevention 

 of these we can only look forward to the day when co-operation of the 

 investigator and the planter has produced some reliable and practical 

 method for their treatment. 



.Time, 1919. 



