FIELD ENTOMOLOGIST. 
7 
cause no injury to trees under ordinary conditions, though it is more 
liable to do injury than properly made lead arsenate. Injury to trees 
from arsenical sprays is more or less dependent upon variety of fruit 
and meteorological conditions at time of or following spraying. A 
practice among some orchard men the past season in Mesa County has 
been to use arsenate of lead for the first and second sprays, and if fur¬ 
ther spraying is found necessary the cheaper arsenite of lime is sub¬ 
stituted. 
Arsenate of lead was used at the rate of 12 pounds paste per 200 
gallons of water in the experimental orchard. 
Arsenite of lime was used at the rate of 1 pound arsenic, 4 pounds 
sal soda, 30 pounds lime per 200 gallons of spray, the arsenic and sal 
soda being boiled together in a small quantity of water for fifteen 
minutes until dissolved, after which the lime slacked with water to 
form a milk was added. , 
, Both arsenate of lead and the arsenite of lime sprays, from their 
white coating upon the leaves, produce a shading effect, which in our 
arid climate serves a secondary beneficial effect by reducing transpi¬ 
ration by the foliage. 
Method or Way to Spray —In the experiments of the year it was 
shown that the method of application had more to do with success 
than a difference of the insecticides used. The variation between poor 
spraying and very good spraying might well vary between 20 per 
cent and 98 per cent, while, as shown, the two insecticides showed 
variation of only about 4 per cent. 
For the 12-year-old apple trees in the experiment at Fruita, 
an average of 12.9 gallons of spray was applied per tree for the first 
spray, and 9.9 gallons were used for later ones. 
For the early spraying a coarser spray of liquid, such as would 
be given by a Bordeaux nozzle or a coarse Vermorel nozzle cap, is 
desirable. At this spraying the tree should be drenched with a strong, 
driving, coarse spray. It should be directed straight into the calyx 
cups that a maximum amount of poison may be placed in position 
there. It was determined by actual count that at spraying time aver¬ 
age apple trees had two-thirds of their blossoms pointing in an up¬ 
ward direction and one-third in a downward direction. It is, then, 
apparent that spray must be directed downward upon the tree as well 
as upward through the branches. It was found necessary with full¬ 
bearing trees, in order to insure thorough work, that spraying be 
directed downward from the top of a tower constructed over the spray 
wagon. Where power outfits are used, and where the rows are of 
such a distance apart that the inner halves of any two can be treated 
from a point midway, it will be found that on medium to large trees, 
two men upon the tower and one man spraying upward from the 
ground will be found most satisfactory. Spray poles eight to twelve 
feet long should be used by both ground and tower men. In one of 
.the experimental orchards the height of tower man’s reach was twenty- 
five feet above the ground. 
