106 JOUENAL OF AGRICULTURE OF P. R. 



Control. 



Certain suggestions can be made which should be effective in 

 reducing to a minimum losses from this source. Until the fruit 

 is fully mature, avoid as far as possible ])icking when the fruit is 

 wet, and when this is not practicable, at least keep the rain aiiJ 

 dew off the picked fruit. Pile the field crates in the packing hous^ 

 so that a maximum of ventilation will be possible. Since the actuj'l 

 burning follows injuries, every precaution must be taken to pre- 

 vent scratching or bruising. 



RUSSETING OR TEAR-STAINING. 



Russeting is caused by several distinct agents, most important 

 of which are the rust mite and the withertip fungus. Rust-mit:* 

 injury is typically brown to black, occurring on tbe side of the irivi 

 exposed to medium light, shaded and full-lighted areas remaining 

 clear. The causal agent in this case is a minute mite, or spider-like 

 animal, which is readily controlled by one to tliree sprayings with 

 lime-sulphur or other sulphur compound, at the time the trouble 

 makes its appearance. 



Russeting due to fungus infection is bro^\^l in color, slighily 

 rough to the touch, and more apt to cover the fruit uniformly, and 

 independent of shading. Infection very often occurs in lines or 

 bands running from the stem to the blossom end in very character- 

 istic manner. This appearance has resulted in the name, "Tear- 

 staining." The markings are entirely superficial, and are produced 

 by slight infections by the withertip and possibly other fungi. In 

 most cases the source of the infection will be found in dead twigs 

 above the fruit which harbor the fungus. The carrying qualities 

 of the fruit are not lowered and there is no further injury, the loss 

 arising from the necessity of placing all such fruit in the lower 

 grades. 



The. points outlined for control of the withertip fungus in its 

 other phases will also apply here. The pruning out of dead wood 

 is of special importance. 



SILVER SCURF. 



A rather common form of l)lemish on citrus fruits is that known 

 as silver scurf or "thrips marks." These are irregular silvery areas, 



