i68 



Bulletin 155. 



2. In the filial results, live scales were found on trees treated 

 with whale-oil soap, one and one-half pounds to a gallon of 

 water ; a i to 15 mixture of kerosene and water ; and quassaine. 

 The insects on all the trees treated with the other materials 

 seemed to be killed but with various effects on the foliage. 



3. A solution of whale-oil soap weaker than two pounds to a 

 gallon of water cannot be relied on to kill the scale. 



4. Of the different kerosene mixtures, the 20 per cent or i to 

 4 mixture gave the most satisfactory results. A 10 per cent 

 mixture may be effective but should not be relied on for the best 

 results. 



5. The practicability of spraying for the San Jose scale is 

 dependent upon conditions. Nursery stock, if badly infested, 

 should usually be burned. 



6. Probably the most satisfactory time to spray for the scale is 

 during its active stage ; that is, during the summer and early fall 

 months. 



7. Fumigating with hydrocyanic acid gas may doubtless be 

 used successfully in many cases. 



San Jose 'icale, 

 natural size. 



10. Oyster-shell bark- 

 louse. Nat. size. 

 Oft 671 tnistaken 

 for the scale. 



