120 DISEASES OF CROP-PLANTS 



become established near the Windward coast, since which 

 discovery the disease has already extended widely and constitutes 

 a grave danger to the future of the principal industry of the 

 island. 



Many districts are too wet for the successful growing of 

 cacao; the crop proved a complete failure in the interior with 

 this apparently as the underlying reason. The principal pro- 

 vision crops are dasheens, yams, plantains and bananas, bread- 

 fruit and various species of peas and beans. They are produced 

 almost entirely by small holders. Temperate vegetables do 

 well at elevations of 1,000-2,000 feet. Coffee was largely 

 grown up to about 1850. The reasons for the failure of the 

 industry are discussed in the introduction to the chapter on 

 the diseases of that plant. 



St. Lucia. 

 St. Lucia is a decidedly mountainous island, approaching and 

 in some districts equalling Dominica in this respect, but with its 

 contours more systematically arranged. There is a central 

 range some 1,500 feet in height, with peaks near its southern end 

 rising above 3,000 feet. From this range ridges run out to the 

 coast in all directions, with numerous narrow, well-sheltered 

 valleys between. Practically the whole island is of igneous 

 material. The average rainfall at Castries is 90 inches, with a 

 range of about 60 to 120 in other districts where records are taken. 



The area of land suitable for arable tillage is for the most 

 part confined to the lower slopes near the coast and to the lower 

 reaches of the valleys. There are several considerable discon- 

 tinuous areas of this kind under sugar-cane, covering about 

 3,000 acres, with four factories of the modern type in operation, 

 and sugar is the highest of the colony's exports in value. The 

 diseases of sugar-cane have had little attention. 



Some 6,000 acres, well scattered through the island, are 

 under cacao, including numerous estates and a large number 

 of small holdings. Pod-rot and canker, due to Phytophthora, 

 are fairly common, but reach to serious proportions only under 

 conditions of exceptional humidity. Dieback is verj^ prevalent 

 among the more neglected of the peasants' plots. Rosellinia 

 root disease is continually troublesome in some situations, 

 and unless control measures are carefully applied slowly bu 

 surely kills out a group of trees around each centre of infection. 



During the last decade the lime industry has attracted 

 considerable attention. An area of some 3,000 acres is planted 

 in the crop, and is still expanding under conchtions which appear 

 to be very suitable. So far the trees have suffered little from 

 specific disease. Some foot-rot has been reported on ill-drained 

 land. Scale insects are well controlled on established trees by 

 entomogenous fungi. 



In the dryer south-western district some trials of cotton 



