
EXPERIMENTS witH Nursery SrTock. 673 
LEAF-BLIGHT OF PEAR SEEDLINGS. 
An extended experiment with pear seedlings in the seed-hed 
was carried on in 1892inco peration with Prof.S. A. Beach, the 
botanist-of the New York State Agricultural Experiment Station. 
_ This experiment was designed to test twenty-five preparations, most 
_ of which were new, with a view of ascertaining their value as pre- 
 yentives of leaf-blight. These preparations were carefully com- 
pounded at the Department, the best theoretical proportions being 
worked out by laboratory experiments. . 
Compounds of copper, iron and zinc were employed, each 
1,000 parts of water used being calculated to have in it one 
part of copper, two parts of zinc, or two parts of iron, according 
to the metal forming the base of the preparation. The metals 
_ were present in the mixtures only as compounds. It should be 
understood that the term “mixture” is here used to designate 
the whole preparation as thrown upon the plant, and consisted 
in each case of the insoluble compound of copper, iron or zinc 
suspended in the water holding in solution the soluble salt of 
the alkali used. The following is a list of the various mixtures 
with their formulae. In all cases when not otherwise stated the 
_ two ingredients were simply dissolved each in one quart of water 
and poured together, the quantity being then made up to one 
- gallon. 
I. Basic cupric acetate mixture: 
‘Basic cupric acetate (refined powder).............. grams 11.90 
Wet up as a thick paste and allowed to stand twenty-four hours 
- or more before dilution in one gallon (3,783 grams) of water. 
i 2, Copper borate mixture: 
Poupric sulphate (bluestone) ...........0.056..084 grams 14.90 
Meodiim porate (borax)... 0.0.66... be eee cece ces grams 16.39 
Re ee eS gallon 1.00 
A -- 3. Copper basic carbonate mixture: 
Cupric sulphate (bluestone) ..............0.-..4.. grams 14.90 
Sodium carbonate (sal soda)...................05. grams 14.90 
TE re MMna WR a Rwy Sailers ea eo eb gallon 1.00 
