362 BOARD OF AGEIOULTUKE. 



thaws the saps lose their vitality, becomnig dark ami discolored. Along 

 the inner bark, at crotches and other cramped places, it lodges and de- 

 stroj's the sap vessels. In the ensuing spring the ascending sap goes up 

 through the inner Avood without obstruction, reaches the leaves, Is 

 digested and starts downward, Avhen it is arrested by the destroyed sap 

 vessels, where it mixes with the accumulations of the frozen sap, and it 

 becomes diseased and bursts through the bark. The bark becomes 

 shriveled, the leaves turn black, and the limb or tree dies." His remedy is 

 the same as for insect blight. 



Since Downing's investigation, several noted horticulturists and sci- 

 entists have given the subject some consideration, but seemingly without 



much real progress. In 1844, the Indiana Horticultural Society, being 

 aroused at the extensive ravages of this disease in our State, appointed a 

 committee composed of Henry Ward Beecher, Reuben Ragan and others, 

 whose names I did not get, who were to make investigation of this disease 

 and report at a subsequent meeting. Mr. Beecher was chairman and 

 made the report. He says that in Indiana and Ohio the blight had pre- 

 vailed to such an extent as to spread dismay among cultivators, destroy- 

 ing entire collections, taking half the trees in large orchards, affecting 

 both young and old trees, whether grafted or seedlings, in soils of every 

 description. Many have seen the labors and fond hopes of years cut off in 

 one season by an invisible destroyer against which none could guard, be- 

 cause in the conflicting opinions none were certain whether the disease 

 was atmospheric, insect or chemical. Much like our situation today. 

 He describes two blights, which he distinguishes as summer blight and 

 winter blight. The former he says affects the leaves in spots; gradually 

 the whole leaf turns russet brown and drops. Along the wood may be 

 seen the hardened trail of a slimy insect of an ash color. 



This is evidently what is now known as the work of the pear slug. 



The winter blight is the same as Downing names the frozen sap 

 blight. 



I will not here attempt to show how Mr. Beecher punctures the theo- 

 ries heretofore ascribed to be the cause of this disease, but will allow you 

 to have the pleasure of reading his full report In the current 1902 report 

 of this Society. He gives as the causes of the blight (the winter blight) 

 the frozen sap theory as described by Downing and he would guard 

 against it by: 



First, Planting in a warm, light, rich, dry and early soil. 



Second. Select trees which complete their growth early in the season. 



Third. Root prune in August or September to prevent late growth. 



Fourth. Cut and burn diseased growth. 



After Mr. Beecher, not much was accomplished until, through the in- 

 vestigations of Professor Burrill, of the Illinois Experiment Station, the 

 origin of the worst form of this disease was attributed to bacteria which 

 propagate by inoculation. This indeed was a very important discovery, 



