DISEASES OF PLANTS. 261 



Through all these experiments i1 was found thai while the methods of culture 

 remained the same, the yield per hill became greater cadi year and the tendency to 

 disease was less apparent. The work with potatoes is being continued, and the 

 author has undertaken to secure immunity through the breeding of resistant strains 

 where the conditions supposed to favor disease are artificially produced and persist- 

 ently maintained. 



A brief accounl is given of experiments on internal tree feeding and medication, 

 which the author states will be fully described in a future publication. It is stated 

 that sufficient facts have been obtained t«» warrant the belief that valuable individ- 

 ual trees may be saved from the action of certain diseases by this method, hut more 

 extensive experiments will he necessary before the work will be adapted to ordinary 

 horticultural practice. 



Report of the botanists, L. R. Jones and W. .1. Morse i Vermont Sta. Rpt. 1904, 

 pp. S8S '/<>:>. After reviewing the occurrence of plant diseases during L904, com- 

 menting briefly on potato blight, arsenical poisoning of potatoes, various diseases of 

 orchard and small fruits, etc., the authors give the results of Bpraying experiments 

 in 1904, discuss the relation of the date of digging to the development of rot and the 

 value of liming for the prevention of potato rot, and describe experiments with 

 formaldehyde gas for the disinfection of scabby potato.-. 



The results of the spraying experiments in 1904 are described at considerable length. 

 This season's work constitute- the fourteenth year in which records have heen kept 

 on the use of Bordeaux mixture forspraying potatoes. In L904 the results obtained, 

 as indicated by the total yield, were not as pronounced as usual, which is attributed 

 to the very late appearance of blight. The early potatoes were practically all out of 

 the way, and in most cases the later varieties had nearly matured before the disease 

 made it- appearance. It is believed that owing to the unusual conditions much of the 

 Bpraying done in Vermont during 1!'()4 was performed at actual loss, hut the average 

 results obtained for the 14 years would indicate that the u-e of Bordeaux mixture, 

 when properly applied, is economically advantageous for the prevention of potato 

 blight. 



In continuation of previous work (E. S. R., 15, p. loss) the authors have investi- 

 gated the relation of the date of digging to the development of rot, and as a result of 

 ."! successive seasons' work they recommend the following as a safe rule for Vermont 

 farm practice: 



"When potato tops have heen killed by the late blight fungus and there is conse- 

 quent danger of rot of the tubers, do not di^r them until a week or- more after the tops 

 were killed. A longer delay will do no harm. With late varieties, where the 

 progress of the disease is slow, do not begin digging until the third week of September 

 at the earliest, and if practicable wait until after the tops are killed by frost." 



\- a result of two years' trials the authors doubt the practical value of lime as a 

 preventive of rot. 



A description is given of the disinfection of scabby potatoes by formaldehyde gas. 

 The authors have devised a method for the treatment «.f seed potato.- in large quan- 

 tity in storage bins, the value of which is shown. A portion of formaldehyde was 

 added to water, and the solution distilled into an air-tighl compartment containing 

 the potatoes, after which the potatoes were allowed to remain in the fumigation 

 chamber for 24 hours or longer. This method of treatment has given highly satis- 

 factory results. 



New work upon wheat rust, II. I.. Bolley {Science, n. ser., : .' 1906 . V 

 pp. ■'>>>, 51). — The author reports a definite establishment of the fact that the uredo- 

 Bpores of Puccinia graminis are able to pass the winter in a viable form. 



Experiments carefully controlled seem to indicate that these spore- may remain 

 unimpaired by the dry winds of autumn and the intense cold ..f a North I tekota w in- 

 ter. In some instances as high as '.to per cent of all spores examined were capable of 



