INSECTS INJURIOUS TO BEANS AND PEAS 1 19 



the same blistering properties, and might be put to the same use. 

 The beetles make their first appearance about the first of July, 

 ravenously devour the blossoms and tender leaves of beans and 

 other vegetables, and, if report speaks truly, they are capable 

 of destroying a crop in a day. 



From the rapidity with which this insect works, poisons are 

 of little value. We must, therefore, resort to mechanical meas- 

 ures, and in their employment promptness and thoroughness are 



Fig. 74.— Ash-gray blister beetle. 

 Fig. 73.— Nuttalls blister beetle. Female at right, twice natural size; 



One-third larger than natural male antenna at left. Greatly en- 



size. (Author s illustration, larged. (Author's illustration, U. S. 



U. S. Dept. Agr.) Dept. Agr.) 



essential. The beetles may be destroyed by driving them into 

 windrows of dry straw or similar material and burning them; 

 by sweeping them into a net, such as is used by insect collectors, 

 and throwing the captured insects into a fire ; or by beating 

 them into specially prepared pans of water on which there is 

 a thin scum of coal oil. 



The Ash-gray Blister Beetle (Macrobasis unicolor Kby.).— 

 This is one of our commonest Eastern species (fig. 74), and 

 although very destructive to beans and peas, is also a serious 

 enemy of beets, potato, and tomato, and attacks besides sweet 

 potato and some flowering plants. 



Blister beetle remedies are discussed on page 68. 



