February, '16] PADDOCK: TURNIP LOUSE 67 



educational systems that will do more than weed out a proportion of 

 those unfit. A man may pass formal examinations with high grades 

 and yet be wholly lacking in the most essential qualities which make 

 for success. 



As a course of study I believe that it is best to give a man a broad 

 general preparation in entomology and then allow him to decide for 

 himself the field in which he wishes to specialize. Some who come 

 to us are not particularly fitted for any aggressive original work, but 

 this is not a difficulty peculiar to college students of entomology. 



Mr. S. J. Hunter: If there is no further discussion we will proceed 

 with the regular order of business. 



President Glenn W. Herrick: We will now pass to the reading 

 of papers. The first paper on the program will be given by Mr. F. B. 

 Paddock. 



OBSERVATIONS ON THE TURNIP LOUSE 



By F. B. Paddock, Texas Experiment Station, College Station 



Work was first undertaken with this species in the fall of 1913. 

 Previous to that time the numerous inquiries which were received 

 indicated that this insect was becoming very destructive over the 

 entire state. When the investigations were started it was supposed 

 that the insect was the cabbage louse. Aphis brassiccc. The state- 

 ments made in literature at that time were that in the South during 

 the winter the cabbage louse was a serious pest of turnips grown as a 

 winter truck crop. 



Very soon after the work was started it became evident that the 

 species under observation was not the cabbage louse. Material was 

 sent to Prof. C. P. Gillette and he determined it as a new species. 

 Aphis pseudohrassiccv, just described by Mr. J. J. Davis. This deter- 

 mination was then confirmed by Mr. Davis. As soon as it was 

 certain that the species under observation was not the cabbage louse, 

 we took the liberty of calling it the "turnip louse," as that would 

 identify it more readily for the truck grower. 



This aphid has been reported to feed on the following hosts, named 

 in order of importance as determined by our studies: Turnip, radish, 

 mustard, rape, collard, rutabaga, cabbage, kale, kohl-rabi, bean and 

 lettuce. It is quite possible that the presence of this aphid on the 

 last two mentioned hosts was somewhat an accident and it is doubtful 

 if the infestation could have persisted. 



The normal form of reproduction in this aphid in Texas is asexual 

 throughout the entire year. It seems that each generation is made 



