678 \1MARY OF CURRENT RESEARCHES RELATING TO 



disease in trees. He used pure cultures of a number of wood-destroying 

 fungi — Schizophyllum commune, Stereum purpureum, Polyporus igniariics, 

 etc. Sensitiveness to disease is connected first of all with the growth- 

 coiidition of the trees ; where they are overshadowed by other trees they 

 are much more liable to infection than are trees in the open. The chief 

 remedy, or rather preventive, against disease is the free entrance of air 

 into the forest. Pruning and attention to wounds are also of importance. 

 Certain fungi also excite to increased growth. 



Plant-diseases in South Africa. — I. B. Pole Evans * records the 

 wide prevalence of potato-scab due to Oospora scabies. He describes 

 the appearance of the disease, which may be introduced into a crop in 

 two ways : by means of contaminated tubers for seed purposes, or by 

 using contaminated manure. He advises growers how to sterilize the 

 seed-potatoes. 



Ethel M. Doidgef contributes an account of a leaf-blight of pear and 

 quince very prevalent in South Africa caused by Entomosporium macv- 

 latum. It destroys the leaves, the young branches, and also the fruits. 

 In the latter it hardens and cracks the skin. The disease can be held in 

 check by spraying with Bordeaux mixture. 



I. Pole Evans % also describes the harm done to peaches by Clado- 

 sporium carpophilum. It causes dark-coloured patches on the fruit, which 

 become hardened and tough. Winter spraying with Bordeaux mixture 

 is recommended. 



Plant-diseases.§ — Jakob Eriksson remarks, on a paper published by 

 E. Voges, that he cannot agree with his statement that red-coloured 

 apples escape infection from Fusicladium, a statement not borne out by 

 experience in Sweden. Eriksson agrees with Voges as to the means for 

 combating the disease : collecting and burning all diseased leaves and 

 fruit and spraying with fungicides. 



A. von Jaczewski|| gives a number of cases in which good results 

 followed the use of fungicides, especially with Bordeaux mixture. He 

 also describes and recommends other solutions, giving the cases in which 

 they would prove of service, especially in cases of hop disease, potato 

 disease, vine mildew, apple blotch, etc. 



Paul SorauerlT describes a case of bitter plums, which was found to 

 be due to the growth of a Ghcosporium, probably a wound fungus, and 

 induced doubtless by a wet season, which caused so many fruits to crack. 



Shot-hole fungus, Cercospora circumscissa, attacks the leaves of peach, 

 almond, cherry, etc., and the part infested by the fungus drops out. The 

 Board of Agriculture have issued a leaflet** describing the disease, and 

 explaining how very serious it is. It is stated that when nursery stock 

 is attacked to the extent of causing defoliation three seasons in succession, 



* Agric. Journ. Union S. Africa, i. (1911) pp. 692-3 (1 pi.), 



t Agric. Journ. Union S. Africa, i. (1911) pp. 694-5 (1 pi.). 



: Agric. Journ. Union S. Africa, i. (1911) p. 696 (1 pi.). 



§ Zeitschr. Pflanzenkr., xxi. (1911) pp. 129-31 (2 figs.). 



i Zeitschr. Pflanzenkr., xxi. (1911) pp. 135-45 (3 figs.). 



f Zeitschr. Pflanzenkr., xxi. (1911) pp. 145-6. 



" Leaflet No. 247 (1911) 4 pp. (3 figs.). 



#* 



