i62 Bulletin 155. 



Lot No. 6. Kerosene, 7 per cent ; water, 93 per cent. 



Lot No. 7. Quassaine, }( lb. to i qt. water. 



Lot No. 8. West's Insecticide, >^ pt. to i gallon of water. 



The first application was made June 16. The weather was clear, with no 

 wind. Young insects had just begun to appear, a small number being 

 found on nearly every infested tree. The second application was July i. 

 The weather was clear, very hot and no wind on this latter date. 



The following notes were taken on the results of the first application : 

 Mixtures No. 3 and 4 seem to be the only ones which have had much effect. 

 On the trees thus treated, there are very few 5'oung insects to be found, 

 indicating that nearly all of the mature insects have been killed by the first 

 applications of clear kerosene and the mixture of 20 per cent kerosene and 

 80 per cent water. There are apparently as many young insects on all trees 

 sprayed with the other solutions and mixtures as there are on the trees 

 which have not been sprayed. The presence of so many young insects on 

 these trees would seem to indicate that the materials used had not been 

 effective in destroying the mature insects. It should be stated in this con- 

 nection, however, that the physical condition of the whale-oil soap used at 

 the time of the first application, was not satisfactory,* 



The third and last application was made July 19. The weather was cloudy 

 and very " muggy." At the time of making this application, the following 

 conditions, results of the first two applications, were noted : 

 No. I. Foliage slightly injured ; trees practically free from young insects. 

 No. 2. Foliage slightly injured ; a few young insects found. 

 No. 3. About 10 per cent of foliage injured ; insects apparently all killed. 

 No. 4. Practically no injury to foliage ; no young insects to be found. 

 No. 5. Foliage uninjured ; young insects numerous. 

 No. 6. Foliage uninjured ; 5'oung insects numerous. 

 No. 7. 50 per cent of foliage injured ; young insects numerous, but 



mature ones show some effect of treatment. 

 No. 8. 75 per cent of foliage injured ; but few young insects alive. 



Results of sprays. — It was intended after the application on July 19, to 



* The whale-oil soap solutions in Nos. i and 2 were applied with a brush and this 

 fact doubtless accounts for the slight injury to the foliage. Only small quantities of the 

 solution came in contact with the leaves. The soap solution used at this time, instead of 

 being of uniform consistency, was of a granular nature ; that is, there seemed to be a 

 very thin liquid (.probably water) in which was a coarse precipitate. In this condition it 

 was impossible to apply it thoroughly, even with a brush. As this difficulty had not been 

 experienced before in using other lots of the same brand of soap, I wrote to the manu- 

 facturers in regard to it. In their reply they suggested that better results might be 

 obtained if the soap were dissolved in moderately hot water and agitated while cooling. 

 This caution was followed in preparing the soap used in later applications, and none of 

 the earlier difficulty was experienced. 



