August, ’20] 
CHILDS: CALYX WORM CONTROL 
337 
of this power, in order to throw a spray of the proper quality must 
maintain a pressure of at least 275 pounds. In the experimental 
work just referred to a machine of this character was used. In order 
to keep the spray in proper form it was tuned up and punished through¬ 
out the season. When one begins to punish a gas engine and pumps 
trouble, then the owner of this machine has his share. This 
condition of affairs existed in many orchards throughout the valley 
and was typical of no particular make of sprayer. A spray machine, 
in order to live the life that it should and at the same time deliver the 
goods must have a liberal reserve. A machine of 10 horse power is 
none too much. Such spray machines are now coming into use and it 
will be only a question of a very few years until all of the present so- 
called modern sprayers will go into the discard. The results given 
in Experiment 7 were obtained with one of these larger types of spray¬ 
ers. The control presented here is undoubtedly better than would be 
accomplished by the average orchardist—it is at least significant. 
The gun where operated with small inferior equipment .has given a 
very poor account of itself. I have carefully checked up the results 
obtained in several orchards where poor equipment has been used. 
The growers tried to do good work and timed their application well. 
Breakdowns and low pressure, which is usually the rule when a ma¬ 
chine is not working right have lead to very poor results. The lower 
fruits as a rule came through the season in fairly good shape. In 1918 
in one of these orchards under observation the following records were 
made. Apples growing below 12 feet developed a worm infestation of 
3.55 per cent. Apples growing between 12 feet and the tops of the 
trees developed an infestation of 17.63 per cent. There is only one 
explanation for this condition and that is the fact that the spray was 
not applied properly to the tops of the trees. 
Low pressure from these small capacity outfits does not produce a 
spray of the proper consistency to accomplish a satisfactory coating. 
The liquid leaves the gun in a coarse, splattering stream. There is no 
fineness of division of the particles and the only way that a tree can 
possibly be covered is to drench and thereby waste much material. 
As I have said before it is my belief that finely divided spray which 
has much the same consistency of the dust particles—which controls 
calyx worms operates in the case of properly applied liquid solutions. 
If this spray is not broken up into a light drifting mist the principal of 
calyx worm control is destroyed and poor results are bound to follow. 
There is no possible chance of obtaining much calyx protection in tops 
of trees with a gun throwing a coarse splattering spray. This might 
possibly be accomplished from a tower. Gravitj^ is the factor which 
allows the poison to reach the calyx ends of the uppermost apples. The 
