148 



Forty-third Report on the State Museum. 



[52] 



The insects on the piece of tui-nip-leaf are a species of plant-louse 



known ?s Aphis brassicce Linn., figures of which are herewith given. 



It is an European species, and 



probably was imported to this 



country at the time of, or soon 



after, the introduction of the 



cabbage. Both in Europe and 



America it has proved to be 



exceedingly destructive to the 



cabbage, although usually it 



fails, through the reduction 

 Fig. 21.— The wia'-ied and wiiigiess viviporous -j. i i 



females of the cabbage aphis. Aphis brassic^. ^ade upon its numbers by its 



enemies, to entirely destroy the crop. Occasionally entire fields 

 have been ruined by its unusual abundance. Its fondness for the 

 rutabaga turnip has long been known, and its injurious operations to 

 tha crop, similar to that above stated, have frequently been recorded. 

 The aphides received are of various sizes, indicating old and young 

 individuals. Among them are a few winged specimens, apparently 

 females. These have been minutely described by Dr. Fitch in his 

 11th Report on the Insects of New York, contained in the Transac- 

 tions of the New York .State Agricultural Society for 1886, vol. xxvi, 

 to which reference may be made. The young are egg-shaped, of a 

 dull pale green color, and looking as if dusted with a grayish powder. 

 Their attennse and legs are blackish; a row of small black dots may 

 in some be seen along each side of the back. 



Remedies. 

 Lime thrown over the infested plants would prove more service- 

 able than plaster. Sprinkling with soap-suds is also recommended, 

 but will seldom kill the older aphides. Probably the greatest benefit 

 would be derived from the use of tobacco water — about a pound of 

 tobacco to a gallon of hot water — the better if the water be applied 

 when quite warm. Pyrethrum powder, or a kerosene emulsion, would 

 also destroy all that could be reached by them. Unfortunately, con- 

 gregating as they do usually, on the under side of the leaves, it is 

 difficult to reach them by ordinary applications. 



Apple-tree Aphis. 

 The insects on the apple twig are the common, destructive, and 

 widespread apple-tree aphis, the Aphis mali Fabr., and is almost 

 always to be found upon the leaves or twigs of our apple trees, but 

 more particularly at the time of the starting of the buds and unfold- 

 ing of the leaves in early spring. Its injuries to the tender vegeta- 

 tion at such time are known to all. 



