540 FETCH : 



is formed after the extrusion of its protoplasm, and hence 

 it is oval from the beginning. 



There is no difference between cultures established from 

 macro- and micro-conidia respectively. 



Other Stages of Thielaviopsis. 



Though Thielaviopsis has been grown in flask cultures on 

 sugar cane extract and artificial nutrient solutions, and the 

 cultures have been kept in some cases for more than six months, 

 no ascigerous or pycnidial stage has been observed. Similarly, 

 notliing of the kind has been found in cultures on agar plates 

 or on blocks of coconut or sugar cane tissue, nor has any other 

 fungus been found in the field which could be united with 

 Thielaviopsis. 



Trichosphceria sacchari Mass., and the Melanconium so 

 common in the West Indies, do not occur on coconut, and they 

 have not yet been found on sugar cane in Ceylon. An asci- 

 gerous species, which has been named Metasphceria cocoes, 

 occurred on coconut leaf stalks, but this is a common sapro- 

 phyte on coconut, and its spores do not produce Thielaviopsis 

 when sown in sugar cane extract. Two fungi are commonly 

 found on coconut tissue attacked by Thielaviopsis , and they 

 are frequently found in flask cultures if the latter have been 

 inoculated with spores direct from the tissue : one of these is a 

 Chromosporium, and the other Pestalozzia palmarum Cooke. 

 Both these have been grown in pure culture, but they do not 

 produce Thielaviopsis. Sphceronema adiposum Butler some- 

 times occurs on diseased coconut wood ; when the spores are 

 sown in sugar cane extract, a mycelium which bears endo- 

 conidia is produced, but these endoeonidia are clearly different 

 from the endoeonidia of Thielaviopsis. 



The " Pineapple " Odour. 



Sugar cane attacked by Thielaviopsis has, according to Went, 

 a distinct odour of pineapples when cut open ; hence the 

 disease of sugar cane caused by the fungus is known as the 

 " Pineapj)le disease of sugar cane." According to Cobb, the 

 odour is not always noticeable, and the strength varies 

 with the variety of cane. 



