DISEASES OF CACAO 159 



in moist air; 0.2-04. mm. in diameter. Spores on short simple sporo- 

 phores accompanied by paraphyses ; ovate or ellipsoid ; when young, 

 one-celled, hyaline, with granular contents, and often extruded in this 

 condition ; when ripe, uniseptate. slaty- or brownish-black, often longi- 

 tudinally striate, usually 25-30 x 12-15 microns. 



Mycelium septate, abundantly developed in the wood, hyaline when 

 young, becoming successively grey, slaty- and brownish-black. Commonly 

 gives to infested wood a slaty-grey tint. 



The spores germinate in water whether in the one-celled or two-celled 

 condition. 



Synonyms: Botryodiplodia Theobromce Pat. 1892. 



Macrophoma vesHta Prill, et Del. 1894. 

 Diplodia cacaoicola P. Henn. 1895. 

 Lasiodtplodia nigra App. et L.iub. 1906. 

 Botryodiplodia elasticoe Petch 1906. 

 Chaelodiplodia grisea Fetch 1906. 

 Lasiodiplodia Theobromct Griff, et Maub. 1909. 

 Diplodia rapax Massee 1910. 



The fungus is very widely distributed and common on a 

 wide range of vegetable material. It is regarded as the cause of 

 one type of cacao pod-rot and occurs as a semi-parasite in ripe 

 sugar-cane. The same or closely similar species cause rots of 

 citrus fruits and cotton bolls in these islands. A species not cer- 

 tainly distinct is associated with the dieback of lime trees. 



The cacao species affects various other trees in a manner 

 similar to that described above in reference to cacao, and in 

 this way has come into prominence on Hevea in Ceylon and 

 Malaya. It appears to be generally distributed throughout the 

 tropical world, having been recorded from North, South, and 

 Central America, the West Indies, Tropical Africa, Ceylon, 

 Malaya, and the East Indies. It has been described under very 

 many names, and it is still in some degree a matter of choice as 

 to which shall be accepted. The genus Diplodia covers a large 

 and ill-differentiated group of fungi which form sunken pycnidia 

 containing two-celled dark spores, and has been subdivided by 

 splitting off new genera under the names Lasiodiplodia, Botryo- 

 diplodia, etc., based on the grouping of the pycnidia and the 

 nature of their surface. The species under notice varies in these 

 characters and has been placed in one genus or another according 

 to the state of the actual specimens examined. The first descrip- 

 tion assignable to it seems to be that of Patouillard, who called the 

 fungus Botryodiplodia Theobromce. Later P. Hennings described 

 it again under the names of Diplodia cacaoicola, by which in 

 consequence of the writings of Howard it became generally 

 known in the West Indies. Bancroft in 1911 claimed to have 

 found the perithecial fructification and described it under the 

 name Thyridaria tarda, which according to rule should rep ace 

 any name given to the pycnidial form. The connection, which was 

 not fully demonstrated, lacks confirmation and the name has 

 not been generally adopted. The fungus is perhaps most :om- 

 monly referred to at the present time as Lasiodiplodia Theobromce , 

 but it is evident that this genus is not based on constant characters 



