33 



by the characteristic stains, this forming brown swollen spots. 

 These spots are evidently formed only in places where the 

 leaves are injured. 



10. The fruits of diseased trees early assume a pale sickly 

 green colour, which is quite different from the dark green 

 colour of normal fruits. Some fruits split and fall while in 

 this condition, bat by no means as many as fall in the next 

 stage of the disease. 



11. When the fruits reach a size of from I to 1| inches in 

 diameter they gradually change colour, turning light lemon 

 yellow and commonly shewing a slight brown exudation in 

 places on the rind. At this stage many fruits fall ; this usually 

 occurs after the appearance of the brown stains, but sometimes 

 before. On trees slightly affected many of the fruits fall early, 

 while on trees badly affected it is seldom that any fruits remain 

 on the tree until they reach full size. The fruits usually split 

 before dropping. At first a slight crack appears around the 

 eye end or apex of the orange, accompanied by a slight 

 gummy exudation. Finally a large split opens across the 

 fruit, exposing the segments and causing the orange to rot 

 and fall. 



12. Both the fruits which fall early and those which come 

 to full maturity are usually more or less disfigured by irregular 

 brown stains, similar to those occurring on the twigs. These 

 stains frequently cover a large portion of the fruit, rendering it 

 unsaleable. 



13. Slight swellings are sometimes found on the rind, parti- 

 cularly in the sour orange. These swellings are caused by gum 

 pockets formed within the tissue of the rind. Very frequently 

 a formation of gum also occurs in the segments immediately 

 around the axis, generally near the seeds. 



14. The fruit of trees affected with die-back usually ripens 

 considerably earlier than that of adjoining healthy trees of the 

 same variety. As a rule, however, it is large, very coarse, thick 

 skinned, and disfigured with brown stains, and in consequence 

 often unsaleable. 



15. The roots of trees affected with the disease usually have 

 a healthy appearance, but in severe cases on improper soils, 

 they frequently become ulcerated and die back for some distance, 

 the dead ends rotting away. Roots which have died back fre- 

 quently have large and somewhat swollen ends from which later 

 on a number of small roots frequently arise. 



The order in which the symptoms appear and their severity 

 vary greatly, but generally are as follows : — The first sign of 



