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FROGHOPPER BLIGHT OF SUGAR-CANE. 



The properties of an alternative crop should be as near as possible 

 to the specifications given below. 



(1) It should be botanically as different as possible from Sugar 

 Caue — i.e. not a member of the order Gramineae, or any related order, 

 in order to eliminate common pests and diseases. 



(2) It should produce a marketable commodity or at least a stock 

 food for use on the estate. 



(3) It should require good and deep cultivation so as to leave the soil 

 in an improved condition for the next cane crop. 



(4) It should require labour at times when this is nob required for 

 other purposes, so as to ensure regular employment of hands. 



(5) It should not be too exhausting to the soil. 



(6) It should, if possible, be a leguminous plant as these add nitrogen 

 salts to the soil, and so improve it and save money in the supply of 

 artificial manures. 



(7) It should leave behind a good supply of trash or haulm to be 

 ploughed in to improve the texture of the seal and increase its humus 

 content, both of which are particularly needed in most of the Trinidad 

 soils. 



The following crops have been tried or recommended for rotation 

 purposes in Trinidad. 



Grass Crops. 



Pasture 



Corn 



Guinea Grass 



Rice 



Leguminosae. 



Alfalfa 



Bengal Beans 

 Pigeon Peas 

 Cow Peas 

 Sword Beans 

 Lima Beans 

 Velvet Beans 

 Soy Beans 

 Woolly Pyrol 



Other Crops. 



Yams. 

 Cassava. 

 Sweet Potatoes. 

 Cotton. 

 Castor Oil. 

 Banana. 



Abandoned Lands. The oldest form of rotation known here con- 

 sisted of growing cane until the crops became poor and then abandoning 

 the land to a mixed growth of grass, cane stumps and bush, (Guava, 

 Black Sage {Cordia cylindrostachya), etc.). This was done more 

 frequently accoi'ding to the amount of land available. I am informed 

 that on one estate a regular sequence of three years canes and seven 

 years abandoned land was kept up for a long period. 



This method is a poor, uncertain, and wasteful form of rotation. 

 The old cane stools left in the ground harbour the froghoppers, moth 

 borers, and root fungi of canes for many months and make it a breeding 

 ground from which they can spread to other fields. The grass which 

 grows between the stools also encourages the froghopper, while the 

 abandoned undrained condition of the field has often an accumulative 

 injurious effect on the tilth and physical condition of the soil, which we 

 have found to be so important in connection with the survival of the 

 froghopper. 



Fasture. The remarks under abandoned land apply partly to 

 pasture in that it harbours insect pests but in Trinidad at least, the 

 froghoppers do not seem to thrive in the close cropped grass, and the 

 more efficient destruction of cane stools makes the field a less dangerous 

 source of other diseases. 



