184 'Phe Philippine Journal of Science ms 



Other fungi have been found on weakened and dead portions 

 of the plant. Aspergillus periconioides Sacc. is commonly found 

 on weakened and fallen leaves. Colletotrichum papayae (Henn.) 

 Syd., Diplodia caricae Sacc, and Didymella caricae Tassi. have 

 been found on dead and dying petioles. Fu^arium heveae Henn. 

 may be found on dead trunks. 



CITRUS SPP. ORANGES, LEMONS, LIMES, POMELOS* 



Citrus culture is carried on in certain sections of the Islands. 

 As is also true with the majority of the other fruit crops, little 

 care is given citrus trees in the way of cleaning up, pruning, 

 spraying, and cultivating. Consequently the trees are sickly, 

 and in many cases they are severely attacked by insects and 

 fungi. 



BARK ROT 



Symptoms. — Citrus trees growing in neglected and poorly kept 

 orchards may be seriously attacked with a bark rot. The first 

 indication of the rot is a slightly raised, sometimes cracked 

 portion, from which usually a drop of gum oozes. These portions 

 gradually increase in size ; gum, in most cases, oozes out in more 

 abundance ; and in the latter stages a froth is present, indicating 

 the presence of yeasts and other saprophytic organisms. These 

 older cracked and rotted portions may be 0.5 to 5 centimeters 

 wide and from 3 to 10 or 15 centimeters long, extending length- 

 wise with the trunk. In the older cases the bark gradually 

 sloughs off, producing an irregular rotted portion in the bark 

 down to the wood. 



An internal symptom of new rots is a slight brownish watery 

 discoloration. Usually there is a green coloration produced just 

 below the rotted portion. This green coloration appears to be 

 due to the abnormal production of chlorophyll. Older rotted 

 portions may also show this greenish coloration, but the diseased 

 parts are more or less brownish and usually covered with a 

 watery frothy substance. A disagreeable odor is present in the 

 older cases of disease. 



Caudal organism. — No work has been done with the causal 

 organism. The disease appears to be produced by a definite 

 organism. 



Control. — Since the cause is not known no definite control can 

 be assigned. Trees that are neglected and given poor culture 

 seem to be more severely attacked. All badly diseased branches 

 should be removed and burned. This with proper culture meas- 

 ures will reduce the disease to a considerable extent. 



