46 SOME INSECTS INJURIOUS TO TRUCK CROPS. 



least, accounts for one beet being badly affected while the adjacent 

 ones are unharmed. In the case of Eutettix strohi and its allies, 

 where most of the leaves of a small plant are affected by the dis- 

 tortion, the plant usually shrivels up and dies, but where only one or 

 two leaves on a large plant are distorted the plant does not appear 

 to be affected at all, and in no case does the color appear in any of 

 the new leaves. In several cases small beets have been seen in which 

 every leaf has been deformed by the work of strohi, and they had 

 apparently stopped growing. 



In the case of the " curly-leaf," however, the abnormal condition 

 apparently spreads from leaf to leaf until finally the whole plant is 

 affected, even though the leafhoppers may have disappeared before 

 the process is complete. This was abundantly demonstrated by the 

 mother beets set out in the spring of 1906. These beets were selected 

 from the best-looking beets of 1905, and would naturally have been 

 ones that showed little or no effect of the " curly-leaf " the season 

 before. In every case observed the first leaves sent up by thesfe beets 

 were as curly as the average of the year before, and most of them 

 formed stunted lettucelike heads, and later withered and died. Some, 

 however, survived through the season, and a few sent up stunted blos- 

 som stalks, but as a seed crop they were an entire failure. This curl- 

 ing took place before any leafhoppers were found in the beets, and 

 in rows adjoining young beets that were not at all affected and did 

 not become affected during the season. This would indicate that the 

 agency, whatever it may be, that causes " curly-leaf " remained in the 

 beet itself over winter and was transmitted to the first leaves in the 

 spring. 



In early September, 1907, the sugar-beet region around Spreckels, 

 Cal., was visited by the writer and a number of cases of what was 

 commonly called " blight " or " curly-leaf " were examined. These, 

 however, proved to be quite different in character from the " curly- 

 leaf " condition caused by Eutettix tenella. The leaves of the beet 

 were found to be covered with pale spots, the edges were turned down 

 instead of up, and the whole appearance w^as quite different. A care- 

 ful search was made over many acres for specimens of tenella., but 

 none was found; instead a species of Empoasca was always found 

 associated with this appearance of the beets. The matter will be dis- 

 cussed further in connection with that sj^ecies (p. 51). 



OTHER RKCORDS. 



Prof. E. G. Titus reports tliat on a trip through the sugar-beet 

 regions of the West in September, 1904, he found Eutettix tenella 

 at La Grande and Echo, Oreg. At La Grande little damage was done, 

 while at Echo one field of 10 acres was so seriously injured by what 



66— IV 



