506 
Dissents from Mr. Downing’s views on insect blight (which seem to be 
mmostly taken from Lowell’s account). He thinks Mr. Downing’s statement 
‘that the sap becomes poisoned must be only conjecture, for it seems ‘‘that 
the sap, after fermentation, was no longer transmissible, and soon dried up.”, 
“Grafts taken froma blighted top, will grow into healthy branches, as I 
have seen.” ‘The injury may be regarded as entirely local.” 
Suggests planting in the lightest soil that the nature of each kind will 
bear ; seeking hardy kinds that make slow growth and ripen their wood 
well; growing thrifty kinds on slow-growing stocks. 
1849. THomMaAsS, JoHN J. American Fruit Culturist, 1849, p. 
201. [23 pages on blight. | 
Same, 1867, p. 157. [23 pages. | 
Same, 1875, p. 157. [24 pages. | 
Same, 1885, p. 163. [23 pages. |] 
This disease is variously called fire-blight, insect-blight, frost-blight, and 
frozen-sap-blight. In all forms ‘‘the appearances are the same—a sudden 
withering and turning black of the leaves on certain limbs during rapid 
-growth, and while the rest of the tree remains apparently in full vigor, the 
-evil extending downwards, unless naturally or artificially checked, till the 
whole tree is destroyed.” The several hypotheses to explain the cause are 
detailed—the heat of the sun’s rays, the insect Scolytus, and the frozen-sap | 
‘theory—and the conclusion arrived at that the real cause is not known. The 
remedy is not so uncertain; it is to immediately cut away the dead branches 
and burn them. ‘‘And, as the poison passes downwards some time before 
its effects are visible externally, the amputation must be made two or three 
feet below the affected part.” Cutting down trees not over ten years old to 
within two feet of the ground as soon as the blight appears in them, has 
been very satisfactory. Among preventives, the early and full ripening of 
the wood in autumn is most important. The Seckel is the variety least af- 
fected by blight. Blight in the apple and quince ‘rarely proves a formid- 
-able disaster.” 
1850. Kennicort, J. A. (Northfield, Ill.) Observations on 
pomology. Rep. Ohio Agric. for 1850, p. 464. [24 pages 
on blight. ] 
Same in Proc. Am. Pom. Soc. for 1850, p. 48. [8 
pages. | 
He made careful observations upon the disease as it appeared in his own 
garden, and as seen elsewhere. It was especially prevalent and severe 
throughout Illinois in 1850. He noticed it first in quince trees about the 
middle of June. They had been heavily loaded with flowers, and the dis- 
ease first showed by the sets withering, and in a few days the extremities 
were blighted. The dead twigs were removed with a knife, but upon ex- 
amination in July the disease still showed. A few apple trees were 
affected about the first of August, and two pear trees. All these were in 
one corner of the garden which had been highly manured and cultivated, 
while the rest had not. 
In passing through the State he found the popular opinion to be that the 
disease was caused by insects. He therefore looked closely for insects, and, 
as “doctors are famous for finding what they look for in post mortem ex- 
‘aminations,” he found insects. The conclusion of his study, however, was 
“that the insects (larve) which killed the twigs did not produce genuine 
