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former spray becomes much more desirable than tbe latter tor most 
work. 
The cost of spraying an orchard depends upon the size of the trees, 
the state of development of the foliage, the presence or absence of wind 
when the sprays are applied, the fineness of the spray used, the 
thoroughness of the work, and the cost of labor and material. 
About 350 prune trees 5 years old were sprayed in the Leslie orchard 
with 600 gallons of modified eau celeste, the application of which 
required three men and a team for thirteen hours. In this work the 
San Jose nozzle was used. The corrosive action of the spray injured 
the plates of the nozzles so that more of the solution was used than 
was required to do the work. The direct throw of the spray added to 
this loss and the loss of time was proportionate. From carefully kept 
records of my own experimental work, it appears that at least 25 per 
cent more material and time was consumed in this orchard than was 
needed if the work had been done with ammoniacal copper carbonate 
applied with a lateral nozzle. This would reduce the spray needed to 
450 gallons, and the time for applying to about ten hours. The cost of 
450 gallons of ammoniacal copper carbonate at $1 per 100 gallons is 
$1.50. Estimating the cost of a man and team at $3 per day, and of 
2 men for applying the spray at $1.50 each per day, the cost of applying 
the spray would be $6 for ten hours, or 60 cents per hour. At this 
rate the total cost is $10.50 for 350 trees, or an average of 3 cents per 
tree for a single spraying. This is not an underestimate, where the 
chemicals are purchased at wholesale prices and properly applied. 
The expense of spraying large trees will be increased in proportion to 
the increase in size. 
The number of treatments necessary to prevent the injurious effects 
of the parasite varies from season to season. In the East the treat¬ 
ments should be more numerous and at shorter intervals than in Cali¬ 
fornia. At present it is believed that in southern California two 
thorough sprayings of the prune tree will sufficiently keep the parasite 
under control. Although no rigid rule can be given as to dates, it 
is probable from the past season’s work that the first treatment may be 
safely made about the time the trees cease to bloom, and when the old 
wood is in nearly full leaf. A second spraying should be made after 
a fair amount of new wood and foliage has been formed. When these 
two treatments are carefully and thoroughly made, say about the 1st ot 
May and again about the 1st of June, varying according to conditions, 
it will rarely be found necessary to treat the trees a third time, unless 
the orchard be situated in a low and damp region. In this case a third 
spraying may be given two to three weeks after the second. 
The dry summers of California allow the spray to remain on the 
foliage until the fall rains, that is, in cases where the applications are 
made after the last spring rains. In the Santa Ana Valley trees 
sprayed in May clearly showed the copper on their leaves as late as 
the last of October. 
