362 BOARD OF AGRICULTURE. [Pub. Doc. 



of a two-tank pump, such as the " Kero water." 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° Beaume or above at 60° F. 

 Petroleum testing lower than 43° at this temperature is dan- 

 gerous 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 destroy- 

 ing 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. 



This soap should be dissolved in water at the rate of two 

 pounds of soap to a gallon of water, by heat, and sprayed 

 between the first of January and the time the buds open. 

 If it is desirable to spray in the fall, this may be clone after 

 the leaves have fallen, using one pound to a gallon of water. 



Treatment with whale-oil soap is probably the most prac- 

 tical for fruit growers to make use of in most cases. 



