INSECTS, DISEASES, AND CONTROL 289 



be called 1-1-10, which is equivalent to -i-i-iO. This is 

 strong enough for use on trees in their dormant condition. 

 Weaker mixtures are used on garden plants and trees bearing 

 leaves. Bordeaux mixture is very successful in the prevention 

 of such diseases as apple scab, peach scab, potato blight, celery 

 blight, tomato blight, cucumber and melon wilt and many 

 others. In combining insect poisons with this mixture the 

 poisons are used in the same quantities as when mixing them 



Fig. 150. — Potato scab disease should be kept out of the soil by planting 

 only such seed potatoes as have been 'treated with formalin as described. (U. S. 

 D. A.) 



with water. Such combinations are most economical as they 

 are combined at the same time, and reduce the amount of 

 labor. Two objects are accomplished in one operation. 



5. Making Kerosene Emulsion. — Take one-half pound of hard 

 soap, shave it very fine and dissolve in one gallon of boiling water. 

 Add it, boiling hot, to two gallons of kerosene or crude petroleum 

 away from the fire. The whole mixture is then stirred or pumped 

 back into itself rapidly. After five minutes of rapid agitation the 

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