62 



large amount (1 bushel to the tree) of well-rotted swamp muck or peat. They have 

 been vigorous up to this year, but within the past month about every twelfth tree 

 on a tract of four acres has mainfested the " die back," beginning in the bud, gener- 

 ally of the highest and most vigorous shoot, and gradually extending downward 

 until in a few instauces it has reached the root, thus killing the entire tree.— (C. H. 

 Franklin, Union Springs, Ala.) 



Answer. Your samples show unmistakable signs of the disease which 

 has come to be generally known as "Pear Blight." This malady is 

 caused by one of the most minute of living organisms — a species of 

 bacterium, named by Professor Burriil, the discoverer, Microccus amy- 

 lovorus. They are frequently spoken of collectively as disease- produc- 

 ing germs, and the malady they occasion belongs to the same category 

 of germ diseases now definitely proven to occur among animals and 

 plants. These germs are of extreme tenuity ; they are borne from place 

 to place and from tree to tree by the atmosphere, which is never so 

 quiet but that its movements are sufficient to keep such impalpable 

 bodies afloat. At present we know of no certain means for rendering 

 the trees insusceptible to the disease. Fumigation, spraying, or wash- 

 ing the trees with various known fungicides, notably sulphur and lime, 

 have given no positive results. As the disease is local and spreads 

 through the tissue slowly, it is possible, as has long been known, to 

 effectually check its progress by amputation. The smaller limbs should 

 be cut off a foot or two below the lowest manifestation of the disease, 

 and the spots on the trunk and larger limbs should be shaved out, cut- 

 ting deep enough to remove all discoloration. The instrument for cut- 

 ting should be kept disinfected with carbolic acid or otherwise, to guard 

 against conveying the disease to freshly cut surfaces. The exposed 

 and newly cut surfaces ought to be at once painted over in order to 

 exclude the germs that might reach them through the atmosphere. 



REMEDY FOR BLACK-ROT OF THE GRAPE. 



Will you kindly inform me if you have any reason to expect good results from the 

 employment of the sulphate of copper remedies in the treatment of black-rot of 

 grapes ? 



Answer. The treatments made this season at Yineland, X. J., by Col. 

 A. W. Pearson, under the direction of the Commissioner of Agricult- 

 ure, render it no longer doubtful that by the proper application of the 

 sulphate of copper remedies we can subdue or entirely prevent black- 

 rot. In the experiments above referred to the Bordeaux mixture, made 

 as follows, has given the most decided results : 



Dissolve pounds of sulphate of copper in 16 gallons of water; in 

 another vessel slake 4 pounds of lime in 6 gallons of water. When the 

 latter mixture has cooled, it is slowly poured into the copper solution, care 

 beiug taken to mix the fluids thoroughly by constant stirring. It is 

 well to have this compound prepared some days before it is required 

 for use. (The sulphate of copper ought to be purchased in a powdered 

 state, as it dissolves with difficulty in the ordinary crystalline form.) 



