330 Pflanzenkrankheiten, 



cies au Phoma sur la Betterave, sont des especes etrangeres, 

 conformement ä l'opinion de Krüger. P. Vuillemin. 



Petch, T., Die-back of Hevea brasiliensis. (Circ. and Agric. Journ. 

 Roy. Bot. Card. Ceylon, p. 304—321. 1910.) 



The fungus, Gloeosporium alborubrum, Petch, which begins this 

 disease attacks the leading green shoot at about the middle of its 

 length, the place attacked becoming dark brown, and the disco- 

 loration then extending upwards and downwards. The progress of 

 the discoloration from the middle of the shoot appears to be pecu- 

 liar to the true fungus ''die-back". After the death of the leading 

 shoot, if it is not removed, a secondary fungus, Botryodiplodia 

 elasticae, attacks the wounds and grows downwards in the woody 

 Stern, gradually killing it to the base. The fructification is produced 

 in the bark and consists of small black spheres filled with spores 

 of the characteristic Diplodia type, oval with a transverse wall 

 across the middle. As the fungus grows down the tree it killsvoff 

 the worls of branches in succession, the parts below meanwhile 

 remaining quite healthy and in füll foliage. The progress of the 

 disease is very rapid, as in man}'- cases the tree is dead within 

 four or six weeks after the death ot the uppermost branches. All 

 diseased parts should be cut away and burnt. 



A critical discussion is given of the identity of the fungus 

 Botryodiplodia elasticae which other Diplodia fungi which grow on 

 various plants in other parts of the world. Some account is also 

 given of climatic leaffall in Hevea, as in sorae seasons the older 

 Hevea trees are extensively defoliated wüthout an}^ trace of disease 

 being present, a State of things which is probably due to some 

 special physiological conditions. W. E. Brenchley. 



Petch, T., Stem Bleeding disease of the Coconut. (Circ. 

 and Agric. Journ. Roy. Bot. Gardens. Ceylon, p. 194—305. 1909.) 



The first part of the paper gives much general formation dealing 

 with the structure of the coconut stem, the effect of the disease and 

 its influence upon the crop, and with its geographica! distribution. 



The outward indication of the disease is a flow of sap from the 

 cracks in the bark. The liquid is somewhat viscid and soon turns 

 black while the bleeding spots occur singly or in small numbers. 

 An examination of diseased stems showed the presence of the 

 hyphae of a fungus, Thielaviopsis ethacetictis, Went, and inoculation 

 experiments proved that this was the true cause of the disease. The 

 fungus produces two kinds of spores, thinwalled oblong microco- 

 nidia, and oval black macroconidia. Both kinds of spores are endo- 

 conidia, i.e. are produced within the conidiophore instead of from 

 the conidiophore. The Thielaviopsis will grow luxuriantly on the 

 inner tissue of the coconut stem probably because of its sugar con- 

 tent, but only feebl}'- or not at all on the leaves and husks, either 

 fresh or fallen. The disease is undoubtedly propagated hy spores 

 which must be somehow transferred from tree to tree. 



Experiments were made on the biology of the fungus and on 

 the effect of various chemicals on its growth. Carbolic acid and 

 copper sulphate in various concentrations will kill the spores or at 

 least prevent germination. It is suggested that all the diseased parts 



