Joint Convention. 199 



the last two seasons and was not troubled witli blight, while his 

 own trees, half a mile from there, blighted badly. He should 

 think, if lieat produced it, that this tree would have been af- 

 fected, as it was a very liot place. lie thought that being shel- 

 tered from the cold northwest winds of winter had some effect 

 upon it. 



Mr. Teffer believed that the air, from some cause, circulated 

 freely there, and that the tree made a slow growth. The soil 

 might be such as to cause a slow growth, and fruiting would 

 have the same effect. Wherever the tree stands in a sheltered 

 position, and makes a rapid growth, it is much more subject to 

 blight than those on the top of a hill, where the air circulates 

 freely, even with the same degree of heat. A pear tree in his 

 orchard, standing in a grove of evergreens, where the sun beats 

 right in, always blights, while others of the same variety, stand- 

 ing on the outside, do not. 



liust on grain comes when we have a hot, still day, with fre- 

 quent rains or heavy dews. Sowing salt or plaster, or seeding 

 the wheat or barley to clover — anything which tends to keep 

 the ground cool, seems to be a preventive of rust. 



In reply to a question of Mr. Kellogg, whether blight did not 

 affect trees on the north side of a house, Mr. Pefter replied that 

 fire blight is seen there, but not rust. Grain along the north 

 side of a fence is safe from rust; the best apples and strawberries 

 are often seen where protected on the south side. 



Mr. Spear regarded this subject as one of great importance. 

 In his observations he had noticed that rust, mildew, and blight 

 generally made tiieir appearance at the same time and under the 

 same atmospheric conditions. By the microscope we find that 

 mildew and rust are caused by fungi, and therefore he concluded 

 that they also caused the blight in the fruit trees. There is a 

 good deal said about fungus growth, but it is little understood. 

 It differs from all the forms of vegetable growth with which we 

 are most familiar, in that while the plants of the latter order have 

 the power to assimilate food taken up by the roots or from the 

 air, the former cannot assimilate food, but only exist on food al- 

 ready prepared. These belong to a lower order of plant life and 



