34 



Bulletin 332 



was made and out of 5^4 eggs, 20.9 per cent had hatched, thus 

 showing conclusively that there was no appreciable increase in 

 hatch after the lime-sulfur was applied. Furthemiore, in compar- 

 ing the percentage of hatch among the sprayed eggs with that of 

 eggs receiving no treatment, it is evident that the following inter- 

 relationship between the percentages should hold. If the lime- 

 sulfur acts as a control, then the percentage of hatch will not 

 increase among sprayed eggs, while normal untreated eggs will 

 continue to hatch. The percentage of hatch, then, in sprayed eggs 

 is a constant number. If such is the case, then the difference (a) 

 between the percentage of hatch in sprayed eggs and the percentage 

 of hatch in untreated eggs should at any time equal the difference 

 (b) between the percentage of normal eggs among the sprayed eggs 

 and the percentage of normal eggs among the untreated eggs plus 

 the dift'erenee (c) between the percentage of shriveled eggs among 

 the sprayed eggs and the percentage of shriveled eggs among the 



TABLE 8 

 Results of Spraying With Lime-Sulfur, and Lime-Sulfur Com- 

 bined With Nicotine When the Nymphs Were Emerging 

 AT John H. Barclay's Orchard in 1918 



untreated eggs. Table 7 shows this comparison for the observations 

 made on April 3, 4 and 5 in experiments 1, 3 and 4. The same 

 relationship will hold for observations made on April 11 and 14, 

 but these have not been included in this discussion. 



The figures in table 6 and 7 show that lime-sulfur sprayed on 

 the eggs of A. avence during the hatching period prevented 99 per 

 cent of the eggs from hatching which had not hatched at the time of 

 application. 



Several careful examinations were made throughout the or- 

 chard during the month of April and only an occasional aphid 

 could be found, one or two per tree. Nearby orchards along with 

 one unsprayed tree in Barclay's orchard showed a heavy infesta- 

 tion, approximately five aphides to a bud. Examinations made 

 the latter part of jMay and in June showed, practically no A. avence 

 on trees sprayed with lime-sulfur or combined lime-sulfur and 



