Studies on Eggs op Apple Plant Lice 



43 



than "Scalecide" 1-40 but when crude carbolic acid or cresol is 

 combined with these two strengths the difference between the re- 

 sults is not as marked. Crude carbolic acid (100 per cent acid), 

 1 part to 99 parts of spray, combined with "Scalecide" 1-15 makes 

 the most effective (100 per cent) kill and also the cheapest killing 

 agent of the three acid combinations tried out. Combinations with 

 cresol U. S. P. are almost as effective as crude carbolic but combina- 

 tions with phenol c. p. are the least effective and also the most 

 expensive. 



TABLE 10 



Experiments With "Scalecide" Combined With Cresol* on 



Selected Eggs op A. AvENi\j: Collected From J. L. Lippincott 



AND Company; Out-op-Doors; Sprayed March 26, 1918 



Number of 

 Experi- 

 ment 



331 

 332 

 333 

 334 

 335 

 336 

 337 

 338 

 339 

 340 

 341 

 342 

 343 



Spray 



Check 

 "Scalecide" 

 "Scalecide" 

 "Scalecide" 

 "Scalecide" 

 "Scalecide" 

 "Scalecide" 

 "Scalecide" 

 "Scalecide" 

 "Scalecide" 

 "Scalecide" 

 "Scalecide" 

 "Scalecide" 



1-15 



1-15, 



1-15, 



1-15, 



1-25 



1-25, 



1-25, 



1-25, 



1-40 



1-40, 



1-40, 



1-40. 



plus cresol 

 plus cresol 

 plus cresol 



plus cresol 

 plus cresol 

 plus cresol 



plus cresol 

 plus cresol 

 plus cresol 



0.5% 



1% 



1.5% 



0.5% 



1% 



1.5% 



0.5% 



1% 



1.5% 



Total 

 Eggs 



106 



106 



75 



Total 

 Hatch 



57 

 9 



Percentage 

 Hatched 



53.7 

 8.4 

 2.6 



ana*IniplntJ^-lres^^°^^^ "^ °"® P^""* meta-cresol, one part ortho-cresol 



Another set of experiments, shown in table 10, were conducted 

 on March 26, 1918 with ''Scalecide" 1-15, 1-25 and 1-40 alone and 

 each in combination with 0.5, 1.0 and 1.5 per cent cresol. The 

 cresol mixture was made up of one part meta cresol, one part ortho 

 cresol and one part para cresol. These experiments show again a 

 decided increase in the effectiveness of the "Scalecide" when cresol 

 IS added. In all cases the 1.5 per cent cresol combinations showed 

 the smallest percentage of hatch, in two experiments a complete 

 kill. The experiments also show that the percentage of hatch in 

 the various strengths of "Scalecide" (alone) varies more than 

 when the same strength of "Scalecide" has a given amount of cresol 

 added to it. In other words, the strength of the oil when in com- 

 binations with cresol is not as important as the strength of the cre- 

 sol. This same thing holds true for crude carbolic when combined 

 with a miscible oil. 



Comparing these foregoing experiments with miscible oils and 

 others of a similar nature conducted this past season with those 

 of 1917, it is evident that a miscible oil spray needs to possess 1.5 

 to 2.0 per cent crude carbolic acid or cresol as it goes on the tree in 



