84 SUMMARY OF CURRENT RESEARCHES RELATING TO 



the various conditions of environment that help or hinder their growth 

 and fermentative activity. Other fungi that have been found to take 

 part in fermentation arc also described, certain Ascomycetes and 

 Hyphomycetes. The final section is devoted to an account of enzymes, 

 enzyme activities of yeast and the chemistry of alcoholic fermentation. 

 A full bibliography adds immensely to the value of the book. 



Fungicides.* — A paper has been issued under the auspices of 

 Cornell University describing the various methods of applying sprays, 

 etc., to diseases in plants, many of these being due to insects. The 

 section dealing with fungoid diseases is written by H. H. Whetzel. In 

 the introduction the grower is recommended to spray for fungous diseases 

 before rains, not after ; as the spores germinate during rain, the plants 

 must be protected before the wet season begins. Further, we are told 

 that, " timeliness and thoroughness are more important factors in the 

 control of diseases than are the particular mixtures of poisons used." 

 In the course of the work these mixtures and the methods of applying 

 them are described. 



Diseases of Economic Plants.f — A text-book on this subject has 

 been prepared by F. L. Stevens and J. G. Hall. They aim at meeting 

 the needs of those who desire to recognize and treat diseases without 

 the burden of long study as to their causes, and they also endeavour to 

 help the student to recognize and name the parasites that are the cause 

 of so many plant diseases. The authors give an historical account of the 

 subject, talk of the importance of plant diseases economically, and de- 

 scribe methods and means of cure. They then go on to the diseases 

 that affect particular crops, and describe these in general terms ; purely 

 microscopic characters being relegated to the Appendix. The book is 

 well illustrated. 



Plant Diseases.:}: — Ernest Voges writes on the possibility of over- 

 coming the Fusicladium disease of apples and pears. He names the 

 varieties of apple-trees that are more or less immune to the disease, and 

 points out that young and very vigorous trees suffer less than old trees 

 or than those in poor soil. He traces the life-history of the fungus, 

 and holds that young shoots are not only attacked, but harbour the 

 fungus during the winter. The most abundant source of infection is to 

 be found in the fallen leaves that are scattered through garden or orchard, 

 and Voges recommends above all things the burning of such leaves. 

 He does not think spraying of the leafless trees of great value, but he 

 advises spraying the growing leaves with Bordeaux mixture. 



F. Gueguen § describes a hyphomycetous fungus which does con- 

 siderable damage to the fruits of the cocoa. He found that it gained 

 entrance to the young seed by the bite of an insect that pierced the 

 capsule to get at the radicle of the embryo. The mycelium of the fungus 

 was colourless, then brown : the spores were simpleand colourless. The 



* Cornell Univ. Agric. Exp. Stat. Bull. 283 (1910) (17 figs.). 



t New York : Macmillan Co. (1910) x. and 513 pp. (3 pis. and 214 figs.). 



% Zeitschr. Pflanzenkr., xx. (1910) pp. 385-93. 



§ Bull. Soc. Mycol. France, xxvi. (1910) pp. 287-97 (2 pis.). 



