The Custard Apple in Queensland. 23 



FIELD NOTES AND RECOMMENDATIONS, &c. 



CUSTARD APPLE DISEASES. 

 Director of Fruit Culture. 



Sir, I have previously reported on the occurrence of diseases on 

 Custard Apple trees, and, in view of the increasing area now being 

 devoted to this excellent fruit, I wish to record some recent observations. 



Certain young custard trees on the property of L. G. Corrie at 

 Garden Island were found in a dying state, and specimens of them were 

 obtained for head office investigation, so as to determine the cause of the 

 disease. 



My inspection of affected trees in various places leads me to believe 

 there are two distinct causes for the sickness or death of these trees 

 and each is characterised by a series of symptoms. 



Collar Rot of Custards. 



I give it this name to distinguish it from the collar rot of oranges 

 and lemons. 



The symptoms of this disease appear as follows: 



1. The leaves near the base of the branches turn yellow abnormally, 

 whilst the remainder of the trees looks vigorous and healthy. 



2. Within about three days after this is first noticed all the leaves 

 on the tree suddenly dry up and generally drop off. 



3. The leafless branches dry up from the tip downwards. 



Unless the tree is treated at the very first appearance of yellowing, 

 death will ensue within a few days. 



Die -back of Custards. 



1. The leaves generally of the weaker or smaller shoots turn brown 

 at the edges. 



2. The shoots become stunted in their growth and die back from 

 the tips. 



3. The foregoing symptoms appear sometimes on only a few 

 branches, and the tree may live a long time in a weak state. 



In view of the fatal character of the collar rot, preventive measures 

 have been recommended in accordance with certain conditions which 

 have been noted as likely to introduce or encourage the disease. 



(a] It has been observed that the disease causes the rotting of the 

 bark of the stock and stops when it reaches the scion, and it is possible 

 that certain species of Anona are more liable to the disease than others, 

 and should therefore be avoided as stocks. 



(6) It seems likely that the disease may gain an entrance at the 

 graft wound, germinating in the exposed cambium and growing down- 

 wards into the roots and around the stem. It is therefore important to 



