992 EXPERIMENT STATION RECORD. 



spots varying from O.OG to 0.25 of au iuch iu diameter, wliicli marked a 

 cbange iu the texture of the leaf at this place. These spots are thought 

 to interfere with the proper mauipulatiou of the tobacco iu the course 

 of its preparatiou. Careful examinations iu many cases failed to show 

 any faugus present, but at other times some tufts of mycelium were 

 observed, but being without spores the fungus could not be positively 

 determined. The author quotes B. T. Galloway, of this Department, as 

 saying that he had made a study of a similar affection of tobacco leaves 

 and considers the spots to be due to drops of water or other matter 

 resting upon the leaves. 



Report of the botanist, L. E. Jones ( Vermont Sta. Rpt. 1895, pp. 

 66-115 J pis. 4, Jigs. <S', dijms. 5). — The results of investigations of the past 

 year are reported upon under the following heads: Potato blight, Bor- 

 deaux mixtuie, disinfection of seed potatoes, orchard diseases and rem- 

 edies, observations regarding oat smut and onion mildew in Vermont. 

 The selection of seed as a preventive of late blight, the various forms of 

 potato blight and their causes, field tests of Bordeaux mixture on pota- 

 toes, and frost injuries to applies and pears have all been reported upon 

 to a considerable extent in Bulletin 49 of the station (E. S. E., 8, p. 138). 



The relation of late blight to weather conditions is considered at some 

 length by the author, and charts are given which show the meteorolog- 

 ical conditions for July and August for four years and the relative 

 amount of jjotato blight in those years. 



A report is given of the potato diseases as they occurred in 1895, in 

 which it is stated that 3 species of fungi were very commonly found 

 upon the diseased leaves. These were Macrosporium solani, a species 

 of Cladosporium, and a species of Alternaria. Studies of the Alternaria 

 show that it is doubtful whether it can gain entrance into living potato 

 leaves, but in all probability it aggravates or increases the diseased 

 conditions when means are provided tor the entrance of the spores into 

 the tissue of the plant. The Cladosporium is clearly a saprophyte, and 

 no extended studies were made of it. The author gives rather extended 

 results of the studies of the Macrosporium, and also discusses the Alter- 

 naria, which has already been referred to. He has sought to ascertain 

 with what forms of potato injury the Macrosporium is associated and 

 whether it is possible to produce diseased spots by inoculating healthy 

 potato leaves growing under normal conditions with spores taken from, 

 pure cultures of the fungus. It was clearly ascertained that much of 

 the injury caused by this fungus is due to tlea-beetle punctures or sim- 

 ilar injuries, but many spots were found in which no relation could be 

 traced to previous insect or other injury. In general it seems to be able 

 to attack any plant weakened by whatever cause. In the investigations 

 of the second point of inquiry it was shown that the spores are able 

 to germinate and infect the healthy living tissues when sown upon it. 

 The genetic relationship between Macrosporium and Alternaria is dis- 

 cussed at considerable length. 



