A CONSIDERATION OF CURLY-TOP IN SEED BEETS. 



27 



The same spring some of the standard varieties of seed beets (see 

 fig. T) were planted at Central Farm, about G miles from our experi- 

 mental field at Garland ; other lots were planted at North Farm, about 

 \\ miles away; at Corinne, about 1G miles away, and at Lehi, about 

 100 miles distant. At these places it was difficult to find a single beet 

 leaf hopper during the entire season. Nevertheless, a like percentage 

 of curly - top appeared 

 among the beets plant- 

 ed at each place. Fur- 

 thermore, there had 

 been planted at Cor- 

 inne some of the appar- 

 ently healthy beets from 

 the badly affected plat 

 at Garland. All these 

 manifested the charac- 

 teristic signs of the 

 disease very early. Nu- 

 merous seed beets were 

 sent from Fairfield, 

 "Wash., and planted at 

 Central Farm in the 

 plat with those just re- 

 ferred to. A m o n g 

 these no curly-top ap- 

 peared. No beet leaf- 

 hoppers could be dis- 

 covered at Fairfield the 

 preceding season. 



During the s a m e 

 spring some beets were 

 sent from Garland to 

 Compton, Cal., to be 

 planted there as seed 

 beets. Most of these 

 developed curly - top, 

 although no leafhop- 

 pers could be found at Compton. None of the factory beets or seed 

 beets grown there became affected. 



These results go to show that the changes set up by beet leaf hop- 

 pers are profound and persistent and that while a beet may have 

 been resistant during its first season to the extent of growing to about, 

 normal size without exhibiting signs of the disease, some reaction 

 has been initiated that will show itself in the manner characteristic 



181 



Fin. 8. — Sugar-beet seed stems showing curly-top symp- 

 toms. Those stems had been denuded of all but single- 

 germ seeds and a few bracts ; the new growth alone 

 exhibited curly-top symptoms. 



