Thielaviopsis paradoxa (de Seynes) v. Hbhnel. 



• BY 



T. FETCH, B.A., B.Sc. 



Thielavioims paradoxa was first found by de Seynes, on 

 pineapples in France, and was described by Mm under the 

 name iSporochisnia paradoxum in 1886. Subsequent^ it was 

 discovered, parasitic on sugar cane in Java, by F. A. F. C. Went, 

 who re-described it as Thielaviopsis ethaceticus. As the cause 

 of disease in sugar cane, it has since been studied by Howard, 

 Massee, PriUieux and Delacroix, Cobb, Lewton Brain, and 

 Butler, all of whom refer to it under Went's name. v. Hohnel 

 found it growing on coconut in Vienna, and showed that 

 Went's fungus was identical with that described by de Seynes. 

 Recently it has been found to be the cause of a stem disease 

 of the coconut palm in Ceylon ; and as it has been under 

 investigation for some considerable time, it has been thought 

 advisable to summarize the observations of previous authors, 

 and to indicate hov/ far they agree with observations made in 

 this country. 



de Seynes. 



As stated above, de Seynes (3) found liis fungus in pine- 

 apples, and, contrary to the experience of subsequent investi- 

 gators, he was not able to grow it on other fruits. The 

 affected pineapples showed, in longitudinal section, a black 

 patch, which evidently originated towards the exterior of the 

 fruit. In advanced cases this patch sometimes extended to, 

 and involved, the bases of the leaves which crown the fruit. 

 (This last observation is in opposition to that of Cobb, but it 

 may be explained on the supposition that de Seynes examined 

 cut fruits only.) From the black patch, especially from its 

 margin, there emerged a white mould, continuous with the 

 mycehum which caused the stain. 



The mycehum of the fungus is described as slender, shghtly 

 branched, hyaUne, and thin- walled, with septa 25-40 [k apart. 



[Annals of the Koyal Botanic Gardens, Peradeniya, Vol. IV., Part VII., Sept., 1910.] 



