MISCELLANEOUS INSECTICIDE INVESTIGATION'S. 27 



ing and sucking insects at the same time. It would appear that it is 

 not well to allow kerosene emulsion and arsenate of lead to stand 

 combined too long previous to its application, if the best results are 

 to be obtained. However, a standing for a day or so would make 

 no material difference, since there is but slight breaking down of the 

 soap. In general, insecticides should not be combined until they are 

 to be used. Anthracene emulsion, 5 per cent, burned the foliage 

 badly. Laundry soap, 3 to 50, was effective against the young aphides 

 only. Arsenate of lead alone, as was to be expected, had little or no 

 effect upon the aphides. The combination of arsenate of calcium with 

 kerosene emulsion is not a desirable one, since an insoluble calcium 

 soap is formed, thereby releasing some free kerosene. 



According to the results of the above experiment a 10 per cent 

 kerosene emulsion should prove effective against the green apple 

 aphis. In one instance, however, not all of the aphides were killed. 

 The nicotine solutions, with a dilution up to 1 to 2,000 combined with 

 soap, were likewise effective aphidicides. Anthracene emulsion, 3 

 per cent, gave satisfactory control, and at this strength caused no 

 foliage injury. The kerosene emulsions under 10 per cent were not 

 satisfactory, neither were the soaps at the strengths tested, except 

 that fish-oil soap, 5 to 50, killed 90 per cent of the aphides. 



FIELD EXPERIMENTS. 



POISON TESTS IN EXPERIMENTAL APPLE ORCHARD. 



The Ben Davis orchard which had been used for experimental pur- 

 poses during the seasons of 1912 and 1913 was again secured for con- 

 tinued investigations. The orchard was in very fair condition and 

 responded very creditably in fruit production, the crop in 1914 being 

 larger than any produced in the past. The experiments included 

 tests of insecticides combined with fungicides, since, in commercial 

 orcharding, a combination spray is usually made. Most of the plats 

 received five spray applications, namely: (1) Dormant application, 

 April 16 and 17; (2) cluster-bud stage, May 5 and 6; (3) when petals 

 dropped, May 23, 25, and 26; (4) three to four weeks later, June 15, 

 16, and 17; (5) nine weeks after petals dropped, July 27 and 28. 

 The orchard was sprayed with a power outfit having a pressure aver- 

 aging about 225 pounds. 



The results of the investigations as reported in the succeeding 

 pages were obtained from an examination of the fruit. Certain trees 

 in each plat are designated as count trees. The dropped fruit from the 

 count trees was picked up and examined weekly throughout the sea- 

 son, and at harvesting time the picked fruit was likewise examined. 

 The more important results of the experiments for the control of the 

 codling moth are herewith reported. 



