122 Journal of the Department of Agriculture. 



NOTES ON SOME SUGAR-CANE MATTERS. 



By Paul A. van der Bijl, M.A., D.Sc, F.L.8., Mycologist, Natal 



Herbarium, Durban. 



I. — The FuNca of Cane. 



The statement is often heard that there are no diseases in cane in 

 Natal and Zululand. True, we have at present no disease threatening 

 the extermination of the sugar industry, but there are here, never- 

 theless, several diseases in cane. According to their nature some 

 reduce the stand of the cane and thus indirectly the yield per acre, 

 others interfere or reduce the formation of sugar by the leaves of the 

 cane plant, while others are responsible for the inversion of the 

 sucrose accumulated in the cane stalk, resulting in a loss of ^ugar. 

 These latter may also be responsible for troubles with crystallization 

 in the mills. 



It is our intention in this caption to briefly review the fungi we 

 have found associated with cane and, through illustrations, to iudicato 

 the symptoms by which they can be recognized in cane fields. 



Roof Disease (Fig. 1). 



A soil fungus common in cane fields is Hiiiiantia stellifera, " the 

 stellate-crystal fungus." This fungiis is evident at the base of the 

 cane, cementing the ])asal leaves together, and when the cane stool is 

 opened interwoven white threads of the fungus arc also seen in the 

 ground between the cane roots. 



In smotliering the young buds tlie fungus lessens the stand in 

 ratoon crops, and it has also been observed to i)revent the growth of 

 planted cuttings. 



It is responsible for killing the rootlets of the cane, and it thus 

 weakens the plants and makes them more liable to attacks by other 

 fungi ; and with a diminished root system the plants are in periods 

 of drought not in the best position to obtain from the soil the water 

 it still contains. Plants having their roots attacked by this fungus 

 invariably suffer more from the effects of drought. 



Under the microscope this fungus is easily distinguislied from 

 all others by the stellate crystals which are borne on branches of the 

 vegetative threads of the fungus. These crystals have given the 

 fungus the popular name of " Stellate Crystal fungus.'* 



In addition to cane, the fungus has been observed on the " um- 

 thente " grass {Imperata arundinocea), and it probably occurs and 

 vegetates on other grasses as well. 



On cane the fungus is of the nature of a weak parasite and 

 control methods sliould aim at thorough cultivation to ensure a 

 vigorous growth of cane, conservation of soil moisture, and aeration 

 of the root system. 



Needless to say, cuttings with leaves cemented together by this 

 fungus should not l)e used for planting purposes. 



