132 FROGHOPPER BLIGHT OF SUGAR-CAXE. 



SECTiON^ x:. 



METHODS OF CONTROL. 



The control of nearly every disease or pest can be considered from 

 two different points of view. First with the idea of preventing th&- 

 occurreDce of the outbreaks, and secondly with the idea of I'educing the 

 numbers of the pest when it has appeared, or lessening the damage that 

 it can do. 



Of recent years the method of prevention has been gradually assum- 

 ing more importance, even in temperate climates where intensive 

 cultivation is practised and numerous facilities for control are easily 

 available. Under the present extensive system of tropical agriculture 

 it becomes still more necessary to adopt methods of prevention, even if 

 these may take many years to produce results, rather than to wait for 

 the disastrous outbreaks which may occur over such wide areas and 

 with such intensity as to render their cure almost impossible. 



Even in those cases where methods are known to deal with the- 

 insect when it becomes abundant, it has to be remembered ihat until the 

 frequency of the attacks can be reduced by preventative measures, the 

 cost of the destruction will continue to be a charge on the estate year 

 after year, whenever conditions are favourable for the multiplication of 

 the pest. 



The sugar-cane is a particularly difficult plant to deal with, under 

 conditions at present existing in Trinidad, with respect to direct 

 destruction of the froghoppers, and it is probable that control will be 

 finally obtained by agricultural methods, which will bring about condi- 

 tions in the fields unfavourable to their rapid increase. 



An outline of such methods is given below, followed by a brief 

 account of the various attempts at cure which have been tried at' 

 various times. 



INDIRECT METHODS. PREVENTION. 



In Section VIII the various factors of the environment have been 

 taken one by one and their influence on the prevalence of blight 

 discussed. In Section IX the important conclusion is reached that 

 nearly all these factors seem to have their effect by altering the moisture 

 of the soil and the humidity of the air just above it. 



To what extent can this I'elation be taken advantage of in devising, 

 methods of prevention ? 



It is immediately obvious that any agricultural process which will 

 get the soil into a condition so that it is less subject to extremes of 

 moisture, will lessen the liability of the canes on that soil to froghopper 

 attack. 



Extremes of dryness and water-logging are encouraged by an 

 agriculturally bad physical condition of the soil, and many processes are 

 known to the experienced planter whereby this evil state can be remedied. 



Soil Improvement. 



Drainage. From what has been said on p. 113 it will be apparent 

 that good drainage is an essential condition of freedon. from blight. 

 The drainage system of many of the estates in Trinidad is at present 



