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producing- a fungicide and also an insecticide for both sucking and 

 biting insects. 



foj Resin tvash. — Within the past few years the resin washes have 

 come into quite general use, especially on the Pacific coast. The inter- 

 est in them has been largely due to the efforts of the U. S. Entomo- 

 logical Division, whose agents were the first to bring the compounds 

 prominently before the public. During the past year Mr. H. J. Webber, 

 an assistant in the Division of Vegetable Pathology, engaged upon 

 work in Florida, has used the resin washes with success in combating 

 sooty mold of the orange and other citrus fruits. The sooty mold is 

 a fungus which usually accompanies the attacks of certain insects. It 

 is especially common in Florida, following the ravages of the white 

 fly {Aleyrodcs citri), and although not strictly speaking a parasite, it 

 injures the host by interfering with transpiration and possibly also 

 in other ways. 



Mr. Webber, in the course of his investigations in Florida, found that 

 the wash could be very quickly i^repared by certain modifications of 

 the formula now generally recommended. The formula most generally 

 used by the U. S. Entomological Division contains liO pounds of resin, 

 5 pounds of caustic soda (70 per cent), 2^ pints of fish oil, and 100 gal- 

 lons of water. Tlie resin and soda are broken uj) and, together with the 

 fish oil are placed in a large kettle, sufficient water being added to cover 

 them. The whole is then boiled for several hours, or "until the com- 

 pound will mix properly in water without breaking up into yellowish 

 flakes." Mr. Webber uses OS jier cent granulated caustic soda and by 

 this means is enabled to avoid the loug-contmued boiling. 



I have experimented with Mr. Webber's fornuila, and for a time was 

 l^uzzled at the results obtained. It was found that by using the amount 

 of caustic soda recommended by him a perfect compound was not 

 obtained. That it was imperfect was shown by the flaky, soap-like 

 masses floating in the clear solution. After considerable experiment- 

 ing it was found that success in making the wash was dependent upon 

 having just enough water and just enough caustic soda. By varying 

 the amounts of either of these ingredients the preparation would show 

 the undesirable flaky masses, which would not dissolve in cold water. 

 However, if the full amount of water was added during the heating- 

 process there was no difficulty, but this is not desirable, as it is of con- 

 siderable practical importance to have the wash as concentrated as 

 possible. The perfect wash, although concentrated, should assimilate 

 readily with cold water, forming a clear, brown solution when ready to 

 apply to the plants. Without going into further details it may be said 

 that as now worked out the formula for the stock or concentrated 

 wash is as follows: 



Resiu 20 parts = 20 poiiuds. 



Caustic soda (98 per ceut) 3 parts = 3 pouuds. 



Fish oil 3 parts = 3 pints. 



Water 120 i)art8 = 15 gallons. 



