392 



STATE HORTICULTURAL SOCIETY. 



THE CELERY APHIS {Rhopalosipum dianthi, Schr). 

 Oedee HEMIPTERA. Faotly APHID^. 



Nearly all plants are troubled with plant lice, or "green fly." On celery 

 the above named species has been very common except from the latter part 



of July till the September rains came. 

 Prof. T. A. Williams of the South 

 Dakota station and Mr. F. A. Sirrene of 

 the Iowa station pronounce it a very 

 common species feedin<^ on many plants. 

 The dark, winged form has been the 

 most conspicuous and so common at 

 times that a dozen or more could be 

 counted on single plants. The very young 

 wingless ones were found early in the 

 season and very late, but through the 

 rest of the season neither young nor old 

 were found. They probably breed on 

 some other plant. Had they continued 

 to breed in the field throughout the season as rapidly as they did in the 

 breeding jar where confined, the plants would have suffered severely. As 

 it is, they did little harm the present season. It would not be surprising 

 if they should acquire a better liking for celery and in a few years should 

 breed on it. As with the Thrip, kerosene emulsion becomes our " helper in 

 the time of need." 



Fig. 11. — The celery aphis ; enlarged and wings 

 spread at A, side view and natural size at B 

 — (original). 



THE CELERY APHALARIA (Aphalaria calthea, Limn). 

 Oedee HEMIPTERA. Family PSYLLID.S;. 



This is another insect very closely related to the celery Thrip and Aphis, 

 that was on the plants in the spring along with these two species and about 



as common. Later in the season it was 

 not found. It is about the size of the 

 celery aphis and is of a yellowish brown 

 color with a reddish tinge. The family to 

 which it belongs is known as " jumping 

 plant lice," because many of the species 

 jamp rather than fly. There are but few 

 of the species known to be injurious, and 

 it is not at all probable that this species 

 will be a serious celery pest. If at any 

 time it becomes so, the best remedy that can be suggested is the kerosene 

 emulsion. 



Fig. 12.— The Celery Aphalaria, enlarged as 

 shown by the line beneath — (original) . 



OTHER LESS COMMON BUGS. 



Besides the species of true bugs already considered, there were several 

 others found less common on celery which were either seen sucking the 

 sap or else known as plant feeders. The most conspicuous one of these is 

 a common stink bug, Euchistus tristigmus. It is a broad flat bug that 

 seems to prefer a mixed diet, as it was not only found with its beak thrust 



