62 SOME INSECTS INJURIOUS TO TRUCK CROPS. 



Professor Titus reports finding an Empoasca common on beets at 

 Chino, Cal., in August, 1907, and states that the beet leaves showed 

 the characteristic spotted appearance, but that no curling was noticed. 

 In his trip in 1904 Empoascas were noticed in several places in Cali- 

 fornia, and quite serious damage from " blight " or " curly-leaf " 

 was found in a few places, but the particular nature of the injury 

 was not observed. 



The Empoascas nearly all pass the winter as adults, hibernating in 

 rubbish and sheltered places near their food plants. In the spring 

 they feed on anything that offers until their food plants start, and 

 then they gather on them, laying eggs in early summer. The young 

 nymphs feed on the underside of the leaf and are quite active and 

 keep out of sight. 



Spraying with kerosene emulsion, 1 part of the stock solution to 8 

 parts of water, proved to be a satisfactory remedy for an Empoasca 

 on potatoes in Iowa some years ago, and no doubt could be used on the 

 beets with success. Burning off rubbish around the field in the late 

 fall would probably reduce their numbers. 



CONCLUSIONS IN REGARD TO " CURLY-LEAF." 



As a result of the above investigations, it appears that there are at 

 least two distinct kinds of " curly-leaf " that have been confused 

 under one name. One, in which the leaves become rough and warty 

 and curl up and in which the beet is stunted and does not recover; the 

 other, in which the leaves remain smooth but show numerous pale 

 spots and in which the edges turn down, and in which, as far as known, 

 the injury is confined to the leaves attacked. The first-mentioned kind 

 of " curly-leaf '' occurs from Grand Junction, Colo., west to the Pacific 

 coast and is the one that has been seriously injurious in the inter- 

 mountain region. This condition is brought about by the attack of 

 the beet leafhopper {Eutettix tcnella), and will, no doubt, be confined, 

 for some time at least, to the southwestern part of the Ignited States, 

 the native home of this insect. The second kind of " curly-leaf " has 

 been found in California quite commonly, and doubtless will be found 

 to occur sparingly at least in the eastern part of the United States, or 

 wherever an Empoasca attacks the sugar beet. 



Besides these two types of this injury it is quite possible that in 

 rare cases other types with still other causes have been seen and not 

 recognized at the time as distinct. Investigations in the California 

 field have been so meager that it is impossible to say as yet which 

 type has caused the greatest injury. In the intermountain region, 

 where most of the work has been done, practically all the injury is 

 known to have been caused by the first type. 



66— IV 



