196 



PESTS OF GARDEN AND FIELD CROPS 



Fig. 244. — The Beet Leafhopper. 

 Enlarged and natural size. Original. 



abling it to jump quickly and take wing readily. The younger stages 

 are similar, but are smaller and wingless. Usually the hoppers 



appear in the beet field suddenly, 

 having fed first on some other 

 plant, probably species of weeds. 

 In hot, dry fields conditions are 

 especially favorable to the pest 

 and unfavorable to the beets, 

 while in fields where the reverse 

 conditions prevail the beets are 

 able to withstand attack. 



Infested fields may be sprayed 

 with a contact insecticide, making 

 the first application just as the 

 young nymphs are found in numbers, and repeating. Kerosene 

 emulsion may be used, diluting the stock solution with 8 parts of 

 water. It is very difficult, however, to hit all the insects with 

 the spray. A drag may be used to turn the leaves over, so as 

 to help to make the application more thorough. 



Frames coated with tar dragged through the fields at the first appear- 

 ance of the adults will catch many, and will help to check injury. 



The Spring Grain-aphis, or " Green Bug" {Toxoptera graminum 



Rond.) 



Occasionally, in recent years, oats, wheat, barley, and sometimes corn 

 have been damaged to the extent of millions of dollars by this tiny 

 louse. It occurs in both winged and wingless forms. The latter is 

 about one twentieth of an inch long, yellowish green, with a faint dark 

 line down the middle of its back. Its eyes are quite black. The 

 winged form is a little larger, has a dark thorax, but otherwise is of 

 the same general appearance. 



Attack comes on suddenly in the spring. Countless billions of the lice 

 appear on young grain, sucking the juice of the leaves, stunting the 

 growing plants or killing them outright. Reproduction goes on rapidly. 

 When the fields in a section attacked are destroyed, or the plants have 



