Jan. 1908.] 



21 



Plant Sanitation. 



The epidermis is raised and split up but covers the fungus. Out of the 

 slit a black powder which is formed of brown uniseptate spores 

 protrudes. If a section is made through the wart-like pustules, there is 

 found under the skin a black cellular stroma, filled with several lockets. 

 These spaces are filled with colourless nonseptace spores. If these are 

 placed in a damp chamber, in about 24-36 hours germination takes place. 

 The colourless spores are therefore adult and mature. If we consider 

 the fungus in respect to its hyaline spores it must be considered a 

 Cystospora (a large genus) or better a Fusicoccum. 



If the brown septate spores really belong to it and are the final end of the devel- 

 opment, the fungus will be a Botryodiplodia. It remains then to 

 establish that these last belong to the fungus. It is very probable but 

 not proved." 



In working out the life history of the fungus, it has frequently been noticed 

 that the colourless spores become brownish in colour and afterwards become septate. 

 Considering that no difference can be noted in the mycelia produced by the two fungi, 

 that the wart-like pustules bear both kinds of spores, and that the colourless cells 

 have been observed to be divided by a single septum, I am of opinion that there is 

 sufficient evidence to conclude that the septate brown spores are the final results 

 (the colourless unicellular cells being the forerunners), and that therefore the fungus 

 must be considered as a species of Botryodiplodia. 



The damage caused by the fungus in the roots of the disorganisation of the 

 cortex cells has been observed, and therefore the effect this has on the cocount plant 

 may clearly be understood. The roots of a healthy plant conduct the water and 

 food in solution from the soil to the leaves, and therefore, when the fungus has 

 destroyed a large number of roots, a reduction in the water-absorbing power of the 

 root system takes place. There are, however, few economic plants that so quickly 

 repair damage to roots as the Palmse, and, therefore, the seat of the injury must 

 extend through a large number of roots before it is of any consequence. 



When a large number of roots are diseased, the water, etc., is absorbed in 

 gradually decreasing quantities, and consequently less food substances are 

 elaborated. 



Young trees do not appear to suffer o any considerable extent, for numerous 

 instances have been noticed of young plants having quite a healthy appearance, 

 while a number of the roots were in a diseased condition. 



When, however, the fruiting period comes on, a large drain is made upon the 

 tree. It is taxed very highly and, if the roots are diseased, wilting or yellowing of 

 the leaves is noticed. It was observed that trees that were just coming into bearing 

 were the most liable to succumb, although many old trees were in a diseased 

 condition. 



When the root system, reduced in extent by the action of the fungus, is in. 

 capable of supplying the needs of the plant, the leaves commence to roll up so 

 as to reduce evaporation. Subsequently the leaves do not obtain sufficient 

 water to keep their tissues alive, and then they gradually begin to turn yellow 

 and to dry up, the leaves are, therefore, unable to carry on their functions» 

 and the whole mechanism is thrown out of action. The general appearance of 

 the plant is that of one suffering from ' drought.' 



The petioles of the leaves are also filled with fungus mycelium. This may 

 be noticed in all dying leaves, for their petioles are blackish in colour. No instance 

 has been found of the mycelium passing from the petioles into the stems of the trees, 

 and if a section be cut through a terminal bud of a freshly diseased tree, a sharp 



