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JOURNAL OF THE ROYAL HORTICULTl P.AL SOCIETY. 



cannot be traced in the leaves. The opinion that a tree which has been 

 once attacked never recovers is erroneous, for, apart from the cases of 

 recovery where the trees were not badly affected, seven cases were 

 recorded of complete recovery where the silvering had extended to the 

 whole of the foliage (p. 9). The disease is most common in stone fruits, 

 laurels, and laburnums, and is occasionally met with in apples, whilst 

 cases are recorded of the infection of a walnut, a pear, and a gooseberry 

 bush. Experiments with Stereum from plums, apples, and laburnums 

 go to show that there is no certain indication that the fungus is capable 

 of adapting itself in any way to a particular host plant (p. 15). 



The relative susceptibility of different varieties of plums has been 

 investigated, and, though little difference was revealed in the way 

 varieties took the disease when inoculated, there is little doubt that the 

 Victoria is amongst those most liable to attack, and it is thought that 

 soft- wooded varieties generally, of which this is one, would be most 

 easily infected, owing to the ease with which their tissues suffer injury 

 in the ordinary operations of cultivating and gathering (p. 18), infection 

 taking place through the wood and not through the leaves. 



The only remedy which has been suggested is the application of 

 iron sulphate, and though this has found favour in New Zealand it has 

 been found of no effect at Woburn (p. 25). The only course to adopt 

 therefore in the present state of our knowledge is the prevention of the 

 spread of infection. Experiments show that, so far as the pruning of 

 silvered trees which contain no dead wood is concerned, there is no 

 danger of infection being carried to other trees by the tools used, but 

 when there is any dead wood on a tree the tools used should be dis- 

 infected by dipping them in paraffin, or in a solution of carbolic acid, 

 before using them again on sound trees (p. 33). Neither is there any 

 power of communicating the infection by anything present in the 

 silvered leaves (p. 28) or by connexion with the roots of a diseased 

 tree. As the fungus only fructifies on dead wood — and this soon after 

 a tree or a branch is dead — when it may become a source of infection 

 to dozens of other trees, the course to pursue with badly infected trees 

 is to burn them as soon as possible (p. 32). When trees are only 

 slightly attacked complete removal of the affected branches may be 

 tried, cutting them off at a point considerably below that at which the 

 silvering is in evidence (p. 33). — A. P. 



Slugs among- Strawberries (La Pom. Fmng. March 1910, 

 p. 68). — Moisten chaffed straw with a 4 per cent, solution of copper 

 sulphate, dry the chaff, and place among the strawberry plants. 



C. H. H. 



Smuts of Sorghum {U.S.A. Dep. Agr., Bur. PL Ind., Cir. 8).— 



This circular deals with the two best known smuts which occur on 

 Sorghum, Sphacelotheca sorghi, the grain or kernel snuit, and 

 Sphacelotheca reiliana, the head smut. Treatment of seed by immersion 

 in formalin solution, or hot water at a temperature of 135° to 140° F., 

 or with copper sulphate solutions is recommended, and proved effective 

 with regard to S. sorglii. The head smut, however, which is far 



