38 



1. Use pure kerosene in January, February or March only. 



2. Use the finest nozzle to the spray pump which can be ob- 

 tained. 



3. Stop spraying any portion as soon as it is wet. 



4. Spray on a bright day, when a slight (not strong) breeze is 

 blowing. 



Crude Petroleum. 



This substance has been recommended as an insecticide for 

 scale insects by Dr. J. B. Smith of New Jersey, where it was 

 first tried in 1898. While perhaps not beyond the experimental 

 stage, as yet, it seems to promise well if precautions be followed 

 in its use. Some of the conclusions drawn from experiments with 

 it are : — 



1. Treatment should be made in .January, February or March. 



2. Crude petroleum is not adapted to summer use. 



3. It kills the scales wherever it comes in contact with them. 



4. It may be used pure, but a more even distribution is obtained 

 by mixing forty parts with sixty of water by means of a two-tank 

 pump, such as the " Kerowater." Do not apply too much. 



5. Use a very fine nozzle. 



6. Spray on a reasonably calm day, when the trees are dry. 



7. Use petroleum testing 43° Beaum6 or above at 60° F. 

 Petroleum testing lower than 43° at this temperature is dangerous 

 to the trees. 



In this last statement lies one of the chief difficulties. Crude 

 petroleum is a very variable substance, and, if it be of too low a 

 degree of the Beaume scale, it is likely to injure the trees. 



Fumigation. 

 "While fumigation is the most certain method of destroying the 

 scale, its use is not usually practicable by fruit growers in this 

 State. Gas-tight tents, large enough to completely cover the 

 trees, are necessary, and are expensive. The gas generated is 

 a very dangerous one, and its use can hardly be recommended 

 to one not familiar with it. It should be used for the treatment 

 of nursery stock before shipment, however, and so many nurseries 

 in this country now have the scale that it is desirable that only 

 fumigated stock be purchased. 



Whale-oil Soap. 

 This is usually a fish-oil rather than a whale-oil soap. It 

 should be liquid when cold even in as strong a mixture as two 

 pounds to a gallon of water. If it contains fats other than the 

 fish oil, it is likely to prove unsatisfactory, and it should therefore 

 be obtained from a reliable manufacturer. Two satisfactory 



