20 BULLETIN 120, U. S. DEPARTMENT OF AGRICULTURE. 
trees. This deficiency can be largely overcome by using angle 
nozzles of a type that throw a long, solid cone of driving spray. 
Such a type of nozzle is illustrated in figure 5. The writers wish to 
lay particular stress on using angle nozzles, which are so constructed 
as to throw the spray at an angle of 45° from the spray rod. Much 
more thorough work can be accomplished with such a nozzle, for by 
turning the rod it is possible to spray from below or above and from 
either side. Care should be taken to cover thoroughly the lower sides 
of the leaves, since that is where most of the mildew infections take 
place. 
The spray deposit on the foliage protects the leaves from infection 
and kills out any patches of mildew that may be present. How- 
ever, summer spraying is of com- 
paratively little value in cleaning 
virulent twig infections, such as 
are shown in Plate IV, figures 1 
and 2, and Plate VI, figure 2. 
This phase of the disease must 
be dealt with by another method, 
which will be discussed under 
* Pruning.” 
WINTER SPRAYING FOR STIMU- 
LATION. 
; Two years of experimental 
ier Se ae Aa ae ae “tas Work have demonstrated that 
ber through an opening at the side and winter spraying with fungicides 
pss Dee ae lteter ah ond Bayete is of no appreciable value in con- 
this construction a long, slender, solid trolling apple powdery mildew. 
ee ee See ae Dyced, Attention has been called to the 
fact that the mildew attacks vigorous foliage much less severely 
than it does that which is puny and slow growing. In this connec- 
tion the value of the foliage stimulation obtained from summer 
spraying has been pointed out, and it is evident that if a stimulation 
of vigorous spring growth can be brought about by a winter spray, 
just that much will be added to the success of the mildew treatment, 
as well as to the improvement of the general condition of the trees. 
As a matter of fact, it has been found that spraying during the dor- 
mant period with crude-oil emulsions, as commonly practiced in the 
Pajaro Valley for scale-insect control, will stimulate a vigorous early 
growth of foliage the following spring. Occasionally a few buds are 
injured by the oil, but material damage is very rarely noticeable. 
