30 



effect of the resin and fish oil saponified by the caustic soda that pro- 

 duces this result — is a very important one. Quite a number of our 

 fruit growers were at first inclined to believe that it is the caustic prop- 

 erty of the wash that destroys the scale insect, and they therefore in- 

 creased the quantity of this particular ingredient, only to find that the 

 wash so constituted is not apparently more fatal to the insects, while 

 at the same time it is very liable to injure the fruit. My own studies 

 and experiments lead me to believe that the above sprays kill for the 

 most part by suffocation. In the course of experimenting I found that 

 a wash composed of the following ingredients : 



Caustic soda t pounds . . 8 



Eesin do 33 



Water enough to make gallons . . 100 



did not prove fatal to as largo a percentage of Eed scale as did one con- 

 sisting of: 



Caustic soda , pounds.. 6 



Kesin do.... 20 



Fish oil pints.. 3 



Water enough to make gallons . . 100 



Now, if it is the caustic property of the wash that proves fatal to the 

 scale insects, it is evident that the wash containing the largest amount 

 of the caustic agent would prove fatal to the largest number of scale 

 insects, but the reverse of this was really the case ; the wash containing 

 the smallest amount of the caustic agent, the caustic property of which 

 was still further lessened by the addition of the oil, proved fatal to the 

 largest number of the insects. On the other hand, the addition of the 

 oil, while reducing the caustic property of the wash, would increase its 

 varnishing qualities, since it is a fact well-known to painters that the 

 addition of oil to a varnish improves its qualities. For these reasons 

 it seems quite certain that it is the suffocating properties of the wash 

 and not its caustic nature that cause it to prove fatal to the scale insects 

 which have been sprayed with it. 



I have seen orange trees that had been sprayed with a wash so caustic 

 that it killed fully nine tenths of the leaves on the trees, burnt the bark 

 brown, and caused nearly all the oranges to drop off, and yet quite a 

 number of the Eed scale insects located on the oranges still remaining 

 on the tree were alive. This will show the utter uselessuess of attempt- 

 ing to destroy the Keel scale on citrus trees by the use of caustic washes. 



THE LIME, SALT, AND SULPHUR WASH FOR THE SAN JOSE SCALE. 



For destroying the San Jose scale (Aspidiotus pemiciosus Comstock) 

 on dormant deciduous fruit trees many growers in this State use a wash 

 composed of the following ingredients in the proportions here given : 



Sulphur pounds.. 33 



Lime do 42 



Salt do 25 



Water enough to make gallons.. 100 



