THE CARROT RUST FLY 



13 



Table 8. Relation of temperature to emergence of carrot rust fly 



in in sectary 



Waltham Mass. May 16-June 22, 1930. 



Table 9. Emergence of carrot rust fly at constant temperatures 

 Waltham, Mas?. 1931-1932. 



A slightly or moderately moist soil is most favorable to emergence. Observa- 

 tions on 400 pupae in 1929 showed that the emergence from dry soil was 33 

 percent, from slightly moist soil 80 percent, and from wet soil 54 percent. In a 

 similar experiment in 1931, using 10 pupae in each cage, soil moistened to 25 

 percent saturation was most favorable. In these studies the soil moisture was 

 controlled by adding sufificient water to maintain a predetermined weight of 

 moist soil in the cages. 



Table 10. Influence of soil moisture on emergence of carrot rust 



FLY AT constant TEMPERATURES 



Waltham, Mass. 1931. 



