242 



Witches' Broom. 



[JULY,. 



The Board have received a report of a disease attacking 

 gooseberry bushes, which has been identified as Botrytis cinerea, 

 a parasite met with on the young shoots 

 Fungus on Fruit of nearly all kinds of fruit trees, vines, 



Trees. N &c, of which a detailed account, with 



(Botrytis cinerea.) ■ • . _ 



coloured plate, was given in this Journal, 



Vol. X., p. 17. Where this disease attacks old wood, the tree 



should be dug up and burned, as the fungus is deep seated in 



the wood and there is no chance of recovery, whereas the danger 



to surrounding plants from spores developed on such diseased 



plants is great. Where young shoots only are attacked, all such 



should be cut off and promptly burned. As a check to the 



spread of the disease, neighbouring bushes should be sprayed at 



intervals of ten days with a solution of potassium sulphide — ■ 



one ounce to three gallons of water. When the young shoots 



are forming in the spring the bushes should be sprayed again. 



This disease is much more prevalent in Britain than is 



generally suspected. It is common on the Continent, where it 



also attacks Abies cephalonica, Link ; Abies 

 The "Witches' ■ . c , ' ^ 



Broom" of the noramanntana, bpach ; and Abies pinsapo, 



Silver Fir. Boiss. In Siberia it has been observed on 



{Abies^pectznata, Abks pichtlh Forbes ; and in North America 



on Abies balsamea, Mill. 

 The " witches' brooms " are caused by a fungus which has 

 been known for a long time as Accidium elatinum, Pers., and 

 although belonging to a group of fungi where the species 

 usually appear under very dissimilar forms, and grow on differ- 

 ent living plants durin^different periods of their development, 

 it is only quite recently that the second condition of the fungus 

 has been detected. This discovery will greatly facilitate the 

 suppression of the disease, which in some instances proves very 

 destructive. 



The accidium state of the fungus attacking conifers causes 

 two distinct forms of disease. The condition most frequent in 

 this country consists of globose or spindle-shaped cankered 

 swellings, often of a large size, on the trunk or main branches. 



