92 JOURNAL OF AGRICULTURE OF P. E. 



As a preliminary to spraying: and as an aid thereto, as mucli 

 as possible should be done in the course of routine operations to 

 remove all sources of infection; that is, the scabby leaves and fruits. 

 As far as the fruit is concerned, this merely means the picking and 

 shipping of it before the new bloom comes on, and need take no 

 particular extra time or nionej^ outlay. With regard to the leaves 

 it should be the aim to take them out, in so far as practicable in 

 the course of ordinary pruning operations. If is quite certain that 

 this work as a special operation will not pay, even if time could be 

 found for it. The point to be remembered in this connection is that 

 the more of the infected material removed, the less there will be 

 required of the spray applications. 



Spraying. 



That scab can be controlled in a practicable manner, though noi 

 eliminated, is certain. Very satisfactory results have been obtained 

 in Florida, and some growers here have had measurable success. 



Practically only two materials have been used or considered as 

 fungicides for scab control. Bordeaux mixture and sulphur, the let- 

 ter generally as lime-sulphur. Tests carried out in Florida, as well 

 as such limited work as has been possible here, have demonstrated 

 that Bordeaux mixture, properly applied, has an efficiency of from 

 pighty-five to ninety-five per cent, while lime sulphur reaches a point 

 of approximately thirty-five to forty pei* cent only. The former 

 has, however, proven very objectionable because of the great increase 

 in the amount of scale following its use, due in large measure to 

 the destruction of various l)eneficial fungi which occur in enormous 

 ■quantities in all Porto Rican citrus groves. If not taken care of 

 in time the scale will, after several Bordeaux applications, become so 

 plentiful as to cause very severe damage, or even tlic deatli of many 

 trees. It has also been suspected of having an injurious effect on 

 citrus trees from a physiological standpoint, and is inore tlian apt 

 to burn the tips of a new flush. 



Lime-sulphur has an opposite effect in so far as it prochiccs re- 

 sults at all. At the strengths (tommonly used it destroys only vcn-y 

 small amounts of scale, but on the other hand does not apparently 

 affect injuriously the beneficial fungi. It is. of course, very effi- 

 cient in destroying rust mites and red spider, in decided eontrast 

 to Bordeaux. 



Sulphur or sulphur compounds in the form of dust have been 



