82 AGRICULTURAL RESEARCH AND THE FARMER : 



besides greatly retarding germination. It is thus probable 

 that many cases of a " poor plant " in wheat have arisen from 

 " pickling " the seed with too strong a solution of copper sulphate. 

 Repeated tests with formalin of varying strengths were then 

 made, and the fact established that sprinkling seed wheat with 

 formalin (i tablespoonful or | oz. (fluid) to i gallon water) using 

 2 gallons to the sack (4 bushels), and then covering over the 

 wetted heap for four hours with sacks moistened with formahn 

 of the same strength, is a complete prevention of smut while 

 not appreciably affecting the germination of the wheat. 



Diseases of Hops. — Since 1917, the question of the immunity 

 of certain forms of the hop-plant to " mould " {Sphcerotheca 

 Humuli) — a disease which in many seasons threatens the 

 prosperity of the hop-grower — has been made the subject of an 

 extended research. Whilst no commercial variety of hop at 

 present cultivated has been found to be immune, the horticultural 

 variety, the " Golden Hop," as well as certain seedlings raised 

 from the " wild hop " in Italy, have been proved to be either 

 immune from, or extremely resistant to, this disease. The 

 possibility of obtaining a commercial variety of hop immune 

 from " mould " is therefore in sight. New seedling varieties 

 of hops, immune to " mould," and others immune to the false 

 nettlehead disease, raised at Wye, are being tested at the East 

 MaUing Research Station in Kent, where also other valuable 

 commercial characters, e.g., yield and brewing value (percentage 

 of resins) are being investigated. 



The Brown Rot Diseases of Fruit Trees. — These diseases which 



are responsible for heavy losses annually to plums, cherries, pears, 



and apples, have been under continuous investigation by the 



Assistant Mycologist for over six years, and the work is still 



in progress. The most recent work is along the following hnes : — 



(i) A " Shoot-Wilt " disease of plum trees has been 



investigated during the last two years. It has been found 



that the fungus, which proves to be identical with the one 



common on the fruit {Monilia cinerea), infects the short 



leafy shoots through the leaves and invades the twigs to 



form cankers. 



(2) A special fruiting form of the fungus, found on old 

 mummified plums which had been placed on the ground, 

 has been shown to be a stage in the life-history of Monilia 

 cinerea referred to above. Though the " Moniha " form, 

 so frequent on the mummified plums while they are still 

 on the tree, is in this country the more serious source of 

 infection, the fact that " mummies " lying on the ground 



