October, '19] PETERSON: APHID EGGS 377 



Sodium sulfo-carbonate chemically known by the formula Na^CS^ 

 and also called sodium thiocarbonate was manufactured for Dr. T. J. 

 Headlee three years ago by the Dow Chemical Co., Midland, Mich. 

 The material was tightly sealed in bottles and had partially crystal- 

 ized when used this season, but the application of a small amount of 

 heat soon melted the crystals. In a few experiments (Expt. 13, 14, 

 15, 20, Table I and Expt. 8-p, 15-p, Table I, etc.) performed on March 

 18 and 21 with the eggs of A. avence and A. pomi a 1-9 dilution killed 

 98 to 100 per cent, a 1-14 dilution killed 79 to 99 per cent, and a 1-19 

 dilution killed 93 per cent. In a similar lot of experiments ordinary 

 laundry soap (1 gm.-200 cc.) was added with no apparent change in 

 the solution and the percentages of kill with the various strengths 

 (1-9, 1-14, and 1-19) were almost identical with the experiments 

 where no soap was used. Fish-oil soap at varying strengths (1 gm.- 

 50 cc, 1 gm.-lOO cc. and 1 gm.-200 cc.) was used with each of the 

 three dilutions (1-9, 1-14, and 1-19) of sodium sulfo-carbonate and 

 in every case the percentage of kill was materially reduced rather than 

 increased as we would expect. Some change probably takes place in 

 the solution when the fish-oil soap is added and this lowers its effi- 

 ciency. A slight precipitate was formed when a strong solution of fish- 

 oil soap (1 gm.-50 cc.) was used. The above experiments with sodium 

 sulfo-carbonate indicate that it is very efficient in killing aphid eggs. 

 It is worthy of further investigation. 



Hydrated lime in a finely divided state was applied in a liquid spray 

 throughout the season on the eggs of A. avence (Expt. 29, 30, 31, and 

 32, Table I) in two strengths (1.75 gm.-50 cc. and 3.5 gm.-50 cc.) 

 with and without the addition of casein-lime (lactic). In no experi- 

 ment with lime by itself did the percentage of kill run over 81 per cent 

 and in most cases it was far below this point. Where casein-lime 

 was added there was a slight increase in the percentage of kill. This 

 is probably due to the fact that the particles of lime become more 

 evenly distributed if casein is present. The addition of casein-lime 

 made a decided increase in the length of time the lime would remain 

 in suspension. Ordinary hydrated lime mixed with water settles 

 immediately unless constantly agitated. Hydrated lime was dusted 

 onto the eggs of ^4. avence on March 7, 1919, and 48 per cent of the eggs 

 hatched. 



"Scalecide," a miscible oil, was given another thorough tryout this 

 season and again the results clearly demonstrate that such an oil at 

 the recommended winter strength, 1-15 docs not kill a sufficient quan- 

 tity of eggs to make it a practical spray for the control of aphis in the 

 egg stage. The greatest percentage of kill was 91 per cent with A. 

 avence and 88 per cent with A. pomi when the eggs were sprayed on 



