ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 385 



trichus. Each straw-blight should, however, be studied independently 

 of the others. 



L. Beille * has written an account of the diseases that affect the cocoa- 

 tree in various countries. He notes that wounded trees are more liable 

 to attack than sound trees, and that in this case the fungus penetrates 

 more quickly and more deeply. He also states that saprophytic fungi 

 on the trees already diseased may become true parasites. The diseases 

 are divided into two series : those that are confined to leaves, stems, 

 fruit, etc., and those that attack any part of the plant. Among the 

 latter he signals " die-back " disease, due to the Pyrenomycetous fungus 

 Lasiodiplodia Theobromse, which attacks stems, roots, and fruits ; it is 

 propagated by the spores, which germinate easily and produce a dark- 

 coloured felted mycelium. When the roots are attacked the trees die 

 very soon. If branches are infected the disease works back towards 

 the tree-trunk. The author recommends burning the diseased trees, 

 the application of quicklime to the roots, and the tarring of wounds. 

 Another severe malady, canker, is due, according to Beille, to the 

 combined action of PhytopMhora and Nectria. The fruits are very 

 specially affected by canker, and when diseased ought to be collected and 

 burned. 



The author also describes a witches' broom, due to Exoascus Bussei 

 in one country, in another to CoUetotrkhum luxificum. The latter fungus 

 also causes hardening of the fruits. Diseases of the trunk are caused 

 by species of Corticium, Marasmius, etc. ; those of seedlings by Ramn- 

 laria necator. The roots are damaged by Hymenochsete, and the fruit 

 by Colletotrkhum, etc. 



L. E. Melchers t publishes a preliminary report of a serious disease 

 of raspberries in America, called " raspberry curl," or " yellows." The 

 disease does not, as a rule, make its appearance until the second year 

 after planting, and is visible in the stunted or dwarfed condition of the 

 plant. The canes and leaves are not withered or blighted by this 

 disease. The leaflets affected become darker green and are noticeably 

 revolutely curled. The severity of curl and the variations and in- 

 tensity of colour depend very greatly on soil and climatic conditions. 

 Hot and dry weather particularly favour the disease. The fruit pro- 

 duced is generally so small and poor that it is not worth picking. 

 Melchers found various fungi in old crowns, but he was not able to 

 connect them with the disease, and so far he has been unable to find 

 any definite organisms causing the injury. He recommends the removal 

 and destruction of plants affected with the curl, as they are in any case 

 worthless for the production of marketable fruit. 



A communication has been received by the Board of Agriculture % 

 from Jakob Eriksson, giving his experience in the sterilizing of soil 

 infected with wart-disease of potatoes. Circumscribed plots were in- 

 fected with small pieces of diseased potatoes, and after some weeks the 

 soil in certain of the ulots was watered with a solution of commercial 



* Journ. Agric. Tropic, 1913, pp. 167-72, 193-7. 



t Ohio Naturalist, xiv. (1914) pp. 281-8. 



% Journ. Board Agric, xxi. (1914) pp. 135-6. 



