812 
June 4.and 5. The next few days were hot with dry southwest winds, the 
thermometer standing at 90° to 96°. ‘The petals soon turned brown, fol- 
lowed by the blackening of the leaves just below the flowers, and the exuda- 
tion of the ‘‘black liquid usually seen with fire’ blight.” Apples and crab 
apples were affected alike, and on both the north ‘and south sides of the 
trees. ‘‘All the trees that were in full bloom during those hot days were 
thus blighted, and in a few days looked as though a fire had run through 
them, while the same varieties standing only a few rods apart that had no 
blossom stems or were not yet in bloom, escaped altogether, not only then, 
but all through the season.” The blight, starting in the flower, passes down 
the flower stem to the shoot, when all the flowers of the cluster become af- 
fected, if they have not been so before. ‘From this point it works down 
in the new wood,” and ‘‘to the leaves surrounding the flower stems.” It is 
easily checked at this stage in apples and crabs by removing the twig or by 
cool weather. In the pear it is liable ‘‘to ran down in the older wood and 
to extend until the tree is killed,” which occurs the ‘‘second year if not the 
first.” Girdling below the diseased part seems to arrest the disease the 
saine as amputation. 
Believes it occurs because there is not a sufficient supply of sap to keep 
the flowers from withering in the hot wind, which is the reverse of the the- 
ory heretofore held by all western fruit growers, the author included, to the 
effect that blight is due to too great abundance of sap. 
Specimens of these blighted blossoms and twigs were sent Prof. Burrill, who 
replied under date of Jan. 19, 1882, that ‘‘there is no question but that your 
idea that the blight starts in the blossoms in these cases is true. It is quite 
new to me, but I now find similar evidences of the fact here.” 
Burrill’s theory of the bacterial cause of blight is not accepted, for the 
experiments failed to convey the disease without puncturing the shoot. 
This appears to show that the bacteria cannot gain access through the un- 
injured parts, and hence could not of themselves start the disease. Blight 
may be caused by frozen sap, ‘‘injuring the cellular structure, so that when 
warm weather sets in fermentation commences.” 
‘‘Remedies are cutting away the limb, or removing the bark on large 
limbs below the diseased part. Apply lime and sulphur to the tree. If 
the weather gives indications of blight, mulch the trees, or apply salt to keep 
the temperature down. 
In the discussion D. McDonald (Verona, Wis.) spoke of a tree standing 
close against the south wall of a stone house, that did not blight, as it 
probably would have done if the heat were the cause of the disease. Mr 
Petfer explained it by supposing that the air must circulate freely there, and 
that the tree makes a slow growth, both of which circumstances would 
counteract the heat. R. P. Speer (Cedar Falls, Iowa) had observed that rust, 
mildew and blight generally made their appearance under the same at- 
mospheric conditions. The germs of fungi and bacteria get into the plant 
when the weather has brought about an undue pressure of sap, and it has 
been forced out at the ends of the shoots. It is doubtful if such germs are 
the direct cause of diseases. It could not be caused by cold weather, as it 
does not always affect tender trees the most, and is often severest when the 
weather has been the mildest. Preventive is to keep down the temperature 
of the soil and to secure slow growth. 
1883. Burriuy, T. J. (Champaign, Ill.) Pear blight and 
peach yellows. Trans. Ill. Hort. Soc. for 1883, p. 46. 
[38 pages on blight. | 
An argument is framed to show that the bacteria accompanying blight are 
the cause of 1t, from the fact of their invariable presence, communicability 
by inoculation, and the analogy with animal diseases. Details in reclaiming 
diseased trees by excision are given. Confirms Mr. Peffers observation of 
the access of blight through the flowers. 

