36 
(2) The ammoniacal solution of copper carbonate as used in this © 
work was less effective against scab than copper carbonate suspended 
in water. 
(3) The Bordeaux mixture was more effective in the experiment than 
either form of the carbonate of copper. 
(4) Paris green was more efficientin preventing scab and more effect- 
ive against insects than any of the other preparations used singly or 
combined. 
EXPERIMENTS IN THE TREATMENT OF PEAR LEAF-BLIGHT, CRACKING, AND SCAB. 
These experiments were carried on in the orchard of Dr. W. 8S. Max- 
well, near Still Pond, Md. Inthe main the work was designed to throw 
light on the following questions: 
(1) A comparison of eight fungicides, each depositing on the foliage 
the same amount of the compound of copper as the ammoniacal ecarb- 
onate of copper solution; (a) as preventives of leaf-blight, cracking, 
and scab; (b) as regards their effect on the healthy wood, leaves, flow- 
ers, and fruit, and (¢) as regards cost. 
(2) A comparison of two fungicides, containing no copper, with the 
foregoing preparations. 
(5) The effect on leaf-blight, scab, and cracking of two treatments, 
one when the flowers were opening and one when the petals were 
falling. 
(4) The effect of three treatments, the first before the flower buds 
opened, the second just as the petals expanded, and the third when 
the petals were falling. 
(5) A comparison of seven treatments with the foregoing, the first 
three given at the same time as those in 4, and the others at intervals 
of two to three weeks up to the time the fruit was two-thirds grown. 
The fungicides used were exactly the same as those employed in the 
‘reatment of black rot of the grape. (See ante, pp. 10-11.) The list is 
as follows: 
(1) Ammoniacal solution of copper carbonate. 
(2) Modified eau celeste. 
(3) Precipitated carbonate of copper solution. 
(4) Copper saccharate. 
(5) Glue mixture. 
(6) Bordeaux mixture. 
(7) Copper acetate. 
(8) Copper chloride mixture. 
(9) Potassium sulphide solution. 
(10) Sodium hyposulphite solution. 
The manner of preparing the foregoing is set forth in the chapter on — 
experiments in the treatment of grape diseases. 
A block of Duchess dwarf trees situated near the center of a large 
orchard was selected for the work. The block contained 111 trees, 
mm 
