574 DISEASES OF CULTIVATED PLANTS 



Cucurbitaria pithyophila (De Not.) forms black, crust-like 

 stromatic patches on the bark of various species of Abies and 

 Pinus. These stromata eventually produce numerous black 

 perithecia. 



Perithecia globose then collapsing ; asci subcylindrical, 

 8-spored ; spores elliptic-oblong or obtusely fusiform, con- 

 stricted as a rule at the centre, 3-4-septate, sparingly muri- 

 form, smoky, 18-25x7-8 /x. : paraphyses slender, sometimes 

 branched. 



A pine disease (Diplodia pinea, Kickx) attacks the leaves 

 and young shoots of various species of Pinus in Europe. 

 The leaves fall prematurely and the shoots are eventually 

 killed, but remain for some years before they fall, and produce 

 annually a crop of spores which infect adjoining branches or 

 trees. The disease is most injurious to nursery stock, as 

 apart from the injury to the young trees, there is the danger 

 of introducing the disease into the forest. The fruit appears 

 under the form of minute black spots, which are usually very 

 numerous on the dead branches, occurring more sparingly on 

 the leaves. Experiments conducted at Kew showed that 

 species belonging to the genus Pinus could be readily infected 

 by the spores, P. strobus and P. silwstris, whereas species of 

 Picea, Abies, and Larix resented all attempts at infection. 

 Quite recently specimens of Pinus insignis and Pinus pinaster, 

 badly attacked by this disease, have been received at Kew 

 from the eastern forests of Cape Colony. The mycelium is 

 most abundant in the cortex and phloem, sometimes extend- 

 ing for some distance along the medullary rays. 



Perithecia minute, black, bursting through the epidermis or 

 cortex. Conidia elliptic-oblong, dark coloured, becoming 

 i -septate, 40-45 X 17-20 /z. 



When nursery stock is diseased it should be removed and 

 burned, otherwise the infection spreads rapidly, and if the 

 fungus is introduced to the forest large trees are attacked, for 

 which there is no remedy. 



Massee, Bd. Agric. Leaflet, No. 199. 



The making and application of Bordeaux mixture. Mr. 

 E. S. Salmon has just published an important and detailed 

 account of the making and application of Bordeaux mixture, 

 the outcome of extensive practical work and observation. 



