152 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



works only under cover of the lichens on the trunk and larger limbs, 

 and apparently does not work on the twigs or younger branches as 

 does the San Jose scale. While the European pear scale is not so serious 

 a pest to fruit trees as is the San Jose scale, nevertheless its manner 

 of working under lichens causes it to be neglected by fruit growers 

 until the trees are badly infested, with consequent loss in vitality. 



SPRAYING EXPERIMENTS IN 1908. 

 PLAN OF WORK AND MAXXER OF APPLICATIOX. 



An orchard badly infested with the European pear scale (see PI. 

 XIII) was selected in February, 1908, and divided into 16 plats of 

 6 to 16 trees each. It was planned to examine a large number 

 of scales in the laboratory from the treated trees of each plat, and a 

 like number from the unsprayed, or check, trees, and also to make 

 field examinations as to the effect of the sprays on the scales, on the 

 lichens, and on the trees. 



The applications of sprays were made February 18, 19, and 20 on 

 plats 1 to 12; and March 3, on plats 13 to 16. A strong hand-pump 

 tank outfit and also a barrel pump were used. No pressure gauge 

 was on the pumps, but pressure was probably not more than 60 to 

 75 pounds. Vermorel nozzles were used. 



SPRAYS USED AXD METHOD OF PREPARATIOX. 



Plat 1, lime-sulphur wash. — This was made after the same formula 

 described for the European fruit Lecanium. 



Plat 2, commercial lime-sulphur solution iV<£ 1. — The stock solu- 

 tion was used at the rate of 1 part to 9 parts of water. 



Plat 3, commercial lime-sulphur solution No. 2. — This spray, of 

 different brand, was used at same strength as preceding. 



Plat 4, commercial 4 V er cen ^ distillate-oil emulsion. — This was used 

 as follows : 



Distillate-oil emulsion gallons. . 3^ 



Caustic soda pound . . f 



Water gallons. . 50 



Plat 5a, home-made 10 per cent distillate-oil emulsion. — This was 

 made according to the following formula: 



Boiling water gallons. . 5 



Fish-oil soap pounds. . 2 



Caustic soda do | 



Distillate (28° Baume) gallons. . 5 



When the water started to boil, the caustic soda was added; then 

 the soap, and finally the oil. The whole mixture was then forced 

 through a pump to emulsify it; it was then poured into the barrel 

 and necessary water (40 gallons) to make 50 gallons of the spray was 

 added. 



