Studies on Eggs of Apple Plant Lice 45 



1-500 over "Scalecide" 1-15 for the control of aphids in the nymph 

 and egg stage. They also bring out the fact that a most careful 

 attempt to "clean up" aphis by adding 40 per cent nicotine to 

 summer strength lime-sulfur at the cluster-cup or pink-bud stage 

 will at times fail. 



A few young trees not over six years old were sprayed with 

 "Scalecide" 1-15 plus crude carbolic acid, 1 part to 99 of the 

 spray (1 per cent solution), on JMarch 18, 1918. These were care- 

 fully observed at the time the leaves came out. On most of the 

 branches of tlie sprayed trees the leaves appeared to be normal, 

 but on a few of the lower branches the buds were backward in 

 opening and some seemed to be dead. Before the combination of 

 "Scalecide" and crude carbolic acid can be recommended as a 

 dormant spray for killing aphid eggs, it will be necessary to give 

 this combination a thorough trial and note its effect upon various 

 varieties of apple trees. 



Soaps 



Common laundry soap, conmiercially called "Fels Naptha", 

 and fish-oil soaps (made from commercial liquid and solid forms) 

 were used chiefly as spreaders in a large number of experiments 

 with nicotine, crude carbolic acid, phenol c. p., cresol U. S. P., 

 ineta cresol c. p., ortho cresol c. p., para cresol c. p., etc. In all 

 these experiments the soap was always given a separate trial in 

 order to determine its influence on the percentage of hatch. Be- 

 sides using laundry .soap as a spreader, a large number of experi- 

 ments were conducted with different concentrations of fish-oil soap 

 (made from both solid and li(|uid forms) and resin fish-oil soap on 

 the eggs of .4. aveiuc in out-of-door experiments throughout Febru- 

 ary and >^Iarch, 1918. In the majority of experiments (tables 4 etc.) 

 where the soaps were used at the rate of 1 gm. to 200 cc. (1 pound to 

 24 gallons) there was a slight reduction in the percentage of hatch. 

 This can be seen by comparing the percentage of hatch among the 

 sprayed eggs with the respective checks. Even though this reduc- 

 tion was small it demonstrates the fact that some of the eggs of each 

 species are much less resistant than others. 



A limited number of experiments were conducted in 1917 with 

 fish-oil soap (exp. G-61 to G-6;3 and 0-64 to 0-67, table 4) and the 

 results indicated that this soap was very effective when in concen- 

 trated form. The results of these experiments, however, were ques- 

 tioned, for unfortunately they were dislodged by a heavy wind and 

 covered with snow for two days before the accident was discovered. 

 In spite of this unfortunate occurrence, these experiments and 

 others indicated that it Avould be advisable to make an extensive 

 study of the effect of different strengths of fish-oil soap on the 



