LASIODIPLOniA. 463 



trees is caused by a fungus (i.e., Botryodiplodia theohromm) 

 wliich also causes tl\e ' brown rot ' of the pods. Tlie die- 

 back disease only affects trees which by some cause (Thrips, 

 witch broom disease, wind, sudden want of shade) are in a 

 leafless or in a nearly leafless condition. The fungus does 

 not affect healthy pods, but causes decay of picked pods, or 

 pods which by some cause or other are wounded, or which 

 have already been attacked by other fungi." Experience in 

 Ceylon* agrees completely with the foregoing. " Dieback " 

 of cacao occurs when the shade has been removed and the 

 twigs killed by the sun, or when they have been severely 

 attacked by HelopeUis ; the Diplodia then develops on the 

 d(3ad tissues, and may kill off the branch still further. Cacao 

 pods develop Botryodiplodia if they have been attacked by 

 other fungi, or if they are picked and stored. There is no 

 doubt that Botryodiplodia is a secondary fungus in diseases of 

 cacao. The name " brown rot " is an unfortunate one, for 

 in the early stages of the disease caused by Phytophthora 

 faberi, the diseased parts of the pod are clear brown. 



On Castilloa, Botryodiplodia has been observed in Ceylon 

 as a wound parasite only : it attacked young trees which had 

 been damaged by fire. On Carica papaya it has been found, 

 in Ceylon, only on felled stems. On Erythrina lithosperma, 

 it is a wound parasite. On Albizzia moluccana it is also a 

 wound parasite, entering the stems after they have been 

 pruned. It is a most common saprophyte on Hevea brasiliensis 

 and Ficus elastica, and if healthy stems of either are cut 

 dowTi and left lying on the laboratory verandah, tliey will 

 develop this fungus witliin a fortnight. But it is a wound 

 parasite in Hevea " dieback," as in the similar disease of cacao, 

 and in tliis case it may kill the tree entirely. It occurs as a 

 saprophyte in Hevea and cacao bark which has been killed 

 by " canker." Its exact status in the case of young Hevea 

 plants and of tea is somewhat uncertain. In the former, 

 it may only attack the " stumps " through injuries inflicted 

 during the planting out, while they are more or less dormant, 

 but, as it is knoMTi to have kiUed " basket plants," it would 

 appear probable that it can live as a soil fungus and attack 

 the roots directly. Tea is undoubtedly attacked through 



