12 
BULLETIN 45, HAWAII EXPERIMENT STATION. 
ing the copper is made insoluble by the use of lime. When the di- 
luted solutions come together minute precipitation membranes are 
formed. In spraying, the plant is covered with a thin layer of these 
minute membranes. The copper in the membranes, rendered slowly 
soluble by the action of the carbon dioxid of the air, forms a solu- 
tion in any minute films and droplets of water on the leaves, which 
prevents the germination of fungus spores. 
The Bordeaux should be applied on both upper and lower sur- 
faces of the leaves and at the highest pressure obtainable to insure 
thorough protection and economic distribution. Each plant should 
be sprayed long enough to cover all parts but not sufficiently long 
to allow the spray to 
collect in drops and 
run off, as in the latter 
case the spray is not 
only wasted but is less 
adhesive. The plants 
will hardly show the 
spray when it has 
been properly and 
thoroughly applied 
with sufficient pres- 
sure and in the desir- 
able misty form. ( See 
fig. 3.) 
Perhaps under Ha- 
waiian conditions 
some variations of the 
formula for Bordeaux 
Fig. 3. — Desirable types of hand sprayers, with extension as given may be found 
rods permitting thorough underspraying of the foliage. advisable Possiblv 4- 
pounds of Milestone and 4 pounds of lime in 50 gallons of the mix- 
ture would do the work satisfactorily. 
Where there is difficulty in spraying plants due to the waxy sur- 
face of the leaves, or where the spray does not stay on owing to heavy 
rains, a sticker made up according to the following formula may be 
used to advantage : 
Resin pound-- 1 
Sal soda (crystals) do y 2 
Water gallon y 2 
The ingredients should be boiled together until a clear brown 
sirupy liquid appears, then cooled and added to 50 gallons of 
Bordeaux mixture (or proportionately for smaller quantities of 
spray). 
