237 



semblés petrified fruits. ') If such fruits are kept in the 

 laboratory, the discoloration is seen to spread over the 

 whole pod, which becomes covered with a coal-black 

 mass of spores. Fruits covered with such a mass of spores 

 are sometimes also found in the field; on examination 

 the spores are found to belong to fructifications of GJme- 

 toOÀplodia. This disease, called in the English West-Indian 

 colonies „brown rot" has a close resemblance to the common 

 „black rot" of cacoa-fruits, which is caused by another 

 fungus, Phytophtora sp., and which sometimes causes 

 considérable damage to young as well as to full-grown 

 fruits. 



Pods suffuring from „black rot" {PliijtopJdont) and from 

 „brown rot" (Chaetodiplodia) are similar in coluur, and 

 before the spores hâve been formed, it is impossible to 

 tell with certainty from the external appearance, with 

 which disease we are concerned. 



At the beginning of the disease, when the fruit has 

 only just been attacked, „black rot" may be distinguished 

 from „brown rot" by cutting off a little of therindofthe 

 pods. In the case of „bla(-k rot" alternating darker and 

 lighter rings are often seen in the plane of section and 

 thèse extend outwards from the focus of infection. Wc 

 hâve not observed such rings in fruits attacked by „brown 

 rot"; hère the rind of the pod has a uniform brown 

 colour when a pièce of it is eut off. 



„Petrified" pods and those, which hâve died of 



1) The pétri li cation ol' the pods is the symptom ol" a disease, 

 caused by (Jollelulrichuni luxijicum ; compare Van Hall aiid 

 Drost, Les balais de sorcière du cacaoyer, provo(iués par Colldu- 

 trirhum luxificiini n. sp. Recueil des travaux botani(pies Néerlan- 

 dais, Vol. IV, 1908. tig. 16. 



Département van Landbouw in Surinarae. Bulletin n". 10, lig. 16 



