Plant Sanitation. 



24 



[Jan. 1908. 



The present system of cultivation of coconuts in Triuidad could be improved, 

 and the attention of all growers of coconuts should be drawn to the progressive 

 German colonists and to the Americans in the Philippines, where modern orchard 

 methods are being successfully practised in the treatment of coconut estates, as 

 improved cultivation would tend to retard the spread of disease. 



Although the complete life-history of the fungus and its method of spread 

 is not yet known with certainty, it would appear that owing to its habit in 

 penetrating and spreading in the living tissues of the root of the host plant, cure i s 

 practically outside the question where a large majority of the roots are permeated 

 with mycelium, and therefore it is probable that only the most drastic measures are 

 likely to provide pemanent relief. 



It cannot be expected that the disease can be entirely eradicated, but, by a 

 method of what is known as " stamping out," the amount of disease may materially 

 be reduced and the fungus kept in check. 



There are six principal ways in which we may hope to attack this disease. 

 They are :— 



(1) Destruction of all diseased material. 



(2) Isolation of diseased areas. 



(3) Resting of infected land before planting ' supplies.' 



(4) Spraying and application of chemicals. 



(5) Improved cultivation and drainage. 



(6) Searching for and propagating disease-resistant varieties.— Bulletin of 

 the Department of Agriculture, Jamaica, pp. 114/22, June and July, 1907. 



TREATMENT OP FUNGUS DISEASES. 



In previous numbers of the Agricultural News, and in other publications 

 of the Imperial Department of Agriculture, the attention of planters in the West 

 Indies has repeatedly been drawn to the principal fungus diseases that affect their 

 crops. It is here proposed to give a brief account of the methods that are com- 

 monly adopted for the prevention of the occurrence and spread of fungus parasites. 



Improved methods of investigation have resulted in a vastly increased 

 knowledge of the nature and causes of disease, and there has also been a correspond- 

 ing advance in the treatments adopted for its prevention. In the control of many 

 fungus parasites remarkable success has been obtained. Some ot the methods 

 have received a wide application, and should by this time have secured the con- 

 fidence of the planter. 



The chief points to be continually kept in mind when discussing the general 

 treatment of fungus diseases may be classed under six heads : (1) care in cultural 

 operations and in the destruction of all diseased plant tissues ; (2) spraying and 

 soaking in disinfectants for destruction of parasites ; (3) rotation of crops ; (4) 

 raising and propagating disease resistant varieties ; (5) avoiding the introduction 

 of new plants from disease-affected localities ; (6) use of good, healthy seed. 



(1) Probably the most common source of plant infection arises through not 

 promptly destroying all portions of plants that have become diseased. Such serve 

 as centres of infection, and if they are allowed to remain, the fungi produce large 

 quantities of spores that may infect healthy areas. The best method for the 

 destruction of such diseased material is, of course, by burning ; and this should 

 be adopted whenever possible. Those plants or portions of plants that will not 

 satisfactorily burn should be buried with lime— on no account should they be left 

 lying about. It has always been recommended that all diseased cacao pods, as 



