58 Biological Studies of Aphis rumicis 



Series D. Eeproduction of Aphis rum wis on Mangolds, 



Sugar Beet, etc. 



One pot each of mangolds, sugar beet, red beet, poppies, peas and 

 dwarf French beans (seed sown 3. 5. 20) was infected with two a. v. ?? 

 from broad beans on 9. 6. 20. These were the stock plants from which 

 four uninfested ones of each species (seed sown 3. 5. 20) were infected 

 with one a. v. ?. The number of aphids produced in 14 days was recorded, 

 and the reproduction figure for each plant is shown in Table VII. The 

 progress of the infestation of the stock plants is given below. 



Mangolds. E. (Carter's Red Chief.) 19. 6. 20. Infected with 2 a. v. ?? from 

 broad beans (offspring of winged migrants on beans). 30. 6. 20. A few aphids pro- 

 duced (three w. v. ?$, remainder a. v. ??). 



Sugar beet. E. (Carter's No. 1 and Klein Wanzleben.) 19. 6. 20. Infected as above. 

 29. 6. 20. Two w. v. $9j remainder a. v. ??, some adult and producing next genera- 

 tion. 



Red beet. E. (Carter's Perfection.) 19.6.20. Infected as above. 30.6.20. A few 

 aphids produced (one w. v. ?, remainder a. v. ??, some adult). 



