12 MANUAL OF FRUIT DISEASES 
of the concentrated solution (testing 32° Baumé) to forty gal- 
lons of water. To this is added arsenate of lead at the rate of 
two pounds (paste; or one pound, powdered) to each fifty gal- 
lons of the diluted lime-sulfur. Aside from its insecticidal 
value, the arsenate of lead increases the fungicidal value of the 
lime-sulfur. Applications should be made as follows: (1) Just 
before the blossoms open, but after the individuals of the clus- 
ter have separated (Fig. 125, page 440). The period for effec- 
tive spraying at this time is from one to three days. This 
application should hold the set of fruit, if the fruit-pedicels are 
thoroughly coated. This is the most important application 
of all in a generally wet season. (2) Spray just after the 
blossoms fall, beginning when they are two-thirds off (Fig. 126, 
page 441). This application gives a clean crop of fruit. The 
period for effective spraying is from two to five days. (3) Ten 
days to two weeks after the second application, depending on 
the weather conditions. In a dry spring this application may 
be omitted. (4) The latter part of July or the first of August. 
Again the grower is to be guided by weather conditions, al- 
though ordinarily this application should not be omitted, as a 
relatively clean crop may be badly damaged by late infections, 
if this application is not made. Sprayings in all cases should 
be done before rain-periods, since the fungicide must be on the 
susceptible part before the pathogene is. Effective fungicides 
do not wash off sufficiently to destroy their efficiency. By 
studying the low barometric areas indicated on the daily 
weather map the orchardist should be able to predict weather 
conditions for two or three days in advance. A nozzle giving 
a fine driving mist should be used. The material should be 
applied at a pressure of 200 pounds. Spraying against the 
wind instead of with it saves materials and labor and gives a 
more effective distribution. Spray from a tower of sufficient 
height to enable the operator to spray the highest parts. Spray 
every season, never omitting the first, second, and rarely 
