41 



markedly; while other varieties are attacked much more severe- 

 ly toy this insect. The cause of this difference is not known; 

 nor is there any definite information on the extent of immun- 

 ity and susceptibility among varieties. In order to find out 

 whether the growers had observed differences in the resist- 

 ance of varieties, the following question was asked: "What 

 varieties resist scale most successfully" ? 



Naturally it will toe difficult to get consistent re- 

 plies to this question, for the growers have only a few var- 

 ieties for comparison. And this comparison must toe based on 

 the few varieties which the individual growers have, which 

 comparison might or might not hold true for varieties in 

 general. A large number of growers had seen no difference 

 in the capacity of varieties to resist scale, but considered 

 all varieties alike in this regard. One man said that "Lime- 

 Sulphur" is the most resistant variety. Table 5 gives a 

 summary of the replies of the growers who had a positive 

 opinion on the question. 



Table 5 . Scale Resistant Varieties . 



Variety Number of growers who considered it so. 



York 42 



Wine sap 26 



Albemarle 13 



Stayman Wine sap 8 



Arkansas 8 



Ben Davis 6 



Rome 4 



Jonathan 3 



