42 Bulletin 332 



4) where crude carbolic acid was added at the rate of 2 parts to 

 98 of miscible oil spray (making a 2 per cent solution), the per- 

 centage of hatched eggs was decreased to 3.9 per cent or a complete 

 kill where "Scalecide" 1-15 was used, and all eggs were killed 

 when the acid Avas added to "Mechling's Scale-Oil". These re- 

 sults show that miscible oils would be much more effective in killing 

 aphid eggs if crude carbolic acid (principally cresol) derivatives 

 were present. 



Comparing the results of the experiment where two heavy 

 miscible oils were used with those obtained by P. E. Jones (12). 

 there is some disagreement. "'Scalecide" is unquestionably a low 

 gravity oil and it was used at the same rate as Jiliscible Oil No. 1, 

 which gave good results in California. This apparent inconsistency 

 in results cannot be explained on the basis of specific gravity, so the 

 question is raised in respect to the presence of phenol or cresols in 

 Miscible Oil No. 1, and also whether these active antiseptic agents 

 were present in the various oils used in the western states where 

 good results were obtained. It is thought that the presence of 

 these chemicals may prove to be far more important than the mere 

 specific gravity of the oil. Possibly one can add crude carbolic 

 acid to oils in general and increase their insecticidal value. 



In 1918 a number of experiments were conducted during Feb- 

 ruary and March with "Scalecide" at varying strengtlis and in 

 combination with crude carbolic acid, cresol U. S. P., and phenol 

 c. p. on the eggs of A. avence out-of-doors at the laboratory. The 

 purpose of these experiments was to determine what piaterial in 

 crude carbolic acid is the most effective agent in killing aphid eggs 

 and how much acid should be added to a miscible oil in order that 

 it might kill 100 per cent of all the eggs with which it came in 

 contact. "Scalecide" was chosen as a favorable oil, for chemical 

 tests show that there was little or no carbolic acid of phenol de- 

 rivatives present in it. Table 9 shows in condensed form the re- 

 sults of these experiments. In the left-hand column the treatments 

 of the series are given, and at the top the date of the spraying 

 and the orchard from which the eggs were collected. In the two 

 spaces for each experiment there are shown the number of hatched 

 eggs (h), the total number of egg?, used, and the percentage of 

 hatch. 



The results of the experiments with "Scalecide" show' con- 

 siderable variation in the respective series, more so than in any 

 other series of experiments with other sprays. These somewhat 

 inconsistent results are not understood ; however, if one studies the 

 table it is seen that the eggs are most susceptible to "Scalecide" 

 (alone or in combination with the acids) near the time when the 

 njnnph emerges, or in other words, when the greatest number of 

 eggs show a split outer covering. "Scalecide" 1-15 is more effective 



