200 Report of the Depautment of Entomology of tub 



Weather chiving tests in Table IX. — Spring treatment. Trees 

 sprayed April 19. Temperature 34°, cloudy with slight rain. 

 Weather durinj;; the week following cloudy with frequent show- 

 ers. Average temperature 48°. 



Tahle IX. — Spring Spraying in Orchard III. 



Ee^^nlts. 



Scales not affoct'efl. 

 Trees nn injured. 



Scales dead, except on 

 some of the small 

 branches where 

 many live ones were 

 found. Trees un- 

 injured. 



SUMMARY FOR ORCHARD III. 



The results in this orchard show only partial success for the 

 treatment. As with the other experiments the 25 j^er ct. 

 emulsion had no noticeable effect on the insect. The lack of 

 thorough work with the 40 per ct. emulsion appeared to be 

 due to the difficulty of reaching every limb and twig on large 

 trees. This seems evident because nearly all of the scales v.-ere 

 dead, the live ones being found only on a few small branches 

 that might easily have escaped thorough treatment. The 

 serious injury to the eight trees sprayed during the winter with 

 the 40 per ct. mixture was unexpected. As apples are not 

 considered especially sensitive to treatment with crude petro- 

 leum and similar insecticides and as the other apple trees in- 

 cluded in the experiments were not seriously injured by similar 

 treatment it seems probable that some other factor besides the 

 petroleum must have had an important inlluence. The apple 

 trees that were uninjured by the winter treatment of 40 per 

 ct. emulsion were not trimmed just before being sprayed as 

 was the case with the injured trees, and as the pruning was 

 unusually severe it may have weakened the trees sufficiently to 

 cause them to succumb to the treatment. 



