INJURY CAUSED BY NON-PARASITIC ORGANISMS 63 



The ground should be treated more especially just outside 

 the evident ring, as that is where the living mycelium is 

 located. 



M' Alpine, Bull. Dept. Agric. Victoria, May, 1898. 



Honeysuckle girdling trees. The injurious effect of the 

 honeysuckle in twining round and girdling the trunks of 

 young dicotyledonous trees is too well known. The effect 

 may be considered curious or ornamental, but if a given tree 

 is required to be a source of profit, or even ornament, it 

 should not, when young, be allowed to serve as a support for 

 the honeysuckle. 



Piercing of tubers. Although scarcely to be ranked as a 

 disease, and certainly not a parasite, it happens every now 

 and again that potato tubers, carrots, etc., are completely 

 pierced and grown through by the underground stolons of 

 twitch or couch-grass Triticum repens (L.). 



Pine-apple heart rot. Pine-apples from the Cape of Good 

 Hope, sent to Kew for investigation, were found to show a 

 blackening or browning of the axis of the fruit. In some 

 instances the discoloration extended throughout the length 

 of the axis, in others the central portion only was discoloured, 

 the two ends remaining sound. A note accompanying the 

 specimens stated that from January to April the fruit remained 

 free from disease, whereas from April onwards the com- 

 mencement of the rainy season a large number of pine- 

 apples were diseased. The disease proved to be of a 

 physiological nature, and caused by excess of moisture in the 

 atmosphere which checked transpiration, thus preventing the 

 translocation of substances in the tissues during the period of 

 ripening. A similar disease occurs in this country when 

 pine-apples grown under glass are exposed to an atmosphere 

 almost saturated with moisture during the period of ripening. 

 A heart-rot of apples of a physiological nature is reported 

 from the United States, when the rainfall is excessive during 

 the period of ripening. 



No preventive measures can be suggested. It would 

 be wise not to have pine-apples ripening during the rainy 

 season. Externally there is not the slightest indication of 

 the disease, which commences at the core, and gradually 

 exiends outwards. 



