512 



[June, 1910 



PLANT SANITATION. 



PLANT DISEASES, 



(Prom the Gardeners' Chronicle, 

 Vol. XLVII., March 26, 1910.) 



So much activity has been devoted 

 in recent years to the investigation of 

 fungal diseases of plants that a Dew 

 work from the pen of an authority on 

 the subject is most welcome, 



It is true that we have in this country 

 the treatises by Mr. Massee, which 

 serve as excellent introductions to the 

 study of plant diseases; nevertheless, 

 we have lacked, hitherto, a text-book 

 which would serve for the student who 

 has passed beyond the elementary stage, 

 and is embarking on a more advanced 

 course. This lack is now supplied by 

 Professor Duggar's new volume in the 

 American Country Life Series.* 



The study of plant diseases is, up to 

 a certain point, so easy and straight- 

 forward that anyone with a microscope 

 and a little patience can pursue it. 

 The spores produced by most parasitic 

 fungi are of definite shapes, sizes and 

 patterns, and hence, by comparing their 

 microscopic appearances with the fig- 

 ures in the text-books, the several pests 

 may be identified. But the trouble 

 begins when the fungus suspected of 

 causing mischief is not in tbe spoking 

 stage. Then, to all but the specialist, 

 the work of identification is well-nigh 

 hopeless, unless means are at hand for 

 keeping the fungus alive under such 

 conditions as are calculated to induce 

 it to form its tell-tale spores. 



Hence the student will be particularly 

 grateful to Professor Duggar for having 

 given, in the first part of his book, 

 instructions for the cultivation of fungi 

 in the laboratory. As he points out, 

 the application of bacteriological me- 

 thods to the cultivation of parasitic 

 fungi is of the highest importance. Nor 

 are these methods difficult of applica- 

 tion ; with the help provided by Pro- 

 fessor Duggar's book, an intelligent 

 student may carry his studies beyond 

 the more empirical stage, which con- 

 sists in the "running down" of tungi, 

 to a stage in which he is able to con- 

 trol their cultivation and thus gain an 

 insight into their peculiar modes of life. 



So important is it that parasitic fungi 

 should be studied in this manner, that 



* fungous Diseases of Plants, by B. M, Dug- 

 gar, Professor of Plant Physiology in the 

 Hew York State College of Agriculture, 

 Cornell University. (Genn & Co., pp. 508. 

 Illustrated. $2*00. 



we could have wished that Professor 

 Duggar had dealt with "methods" 

 even yet more fully. The information 

 given in the seven chapters which make 

 up Part I (on Culture Methods and 

 Technique) is sound, and includes me- 

 thods of isolation, preparation of pure 

 cultures, and the technique of micros- 

 copical preparations. 



Part II. consists of descriptions of 

 parasitic fungi and of the methods 

 whereby they may he kept in check. 

 The perusal of this work demonstrates 

 at once its excellence and the very 

 primitive state of our knowledge with 

 respect to preventive methods. The 

 references to original memoirs, given 

 at the head of each chapter, should 

 prove of considerable service to the 

 student, and must also give him— if, 

 perchance, he is a native of this country 

 — some food for reflection. For although 

 one of the pioneers of plant pathology 

 was the British botanist, Berkeley, of 

 recent years, with three or four dis- 

 tinguished exceptions, our botanists 

 appear to have almost deserted this 

 field of investigation. 



This is the more unintelligible, since 

 not only may a study of fungal dis- 

 eases lead to advances of the greatest 

 practical importance, but it is bound 

 also to advance botanical science uo 

 less considerably. 



It is hardly au exaggeration to say 

 that our only method of coping with 

 these agents of plant diseases is that 

 of spraying ; but spraying, important 

 as is undoubtedly is, cannot be the last 

 word of advice of science to the prac- 

 tical man. 



Truth to tell, the aetiology of plant 

 diseases remains in large measure for 

 the future to discover. New methods 

 are required. The enormous progress 

 made in the combatiug of human dis- 

 eases — progress which a few years ago 

 the pessimist would have pronounced 

 impossible — encourages us to entertain 

 the conviction that new modes of at- 

 tacks on fungal pests will bo devised. 



Is it too much to hope that some of 

 the botanical laboratories of this country 

 will take up, methodically, this pro- 

 mising line of research? In it science 

 and practice meet, and have much 

 ground in common. 



But though our perusal of Professor 

 Duggar's book has suggested to us how 



