66 



about 21/2 mm. in length. The eggs are usually laid in niches along the 

 sides of a tunnel cut in the crown or along the root. The grubs bore 

 through the substance of the root, often riddling it completely, and 

 eventually causing the death of the plant. Injured plants frequently break 

 off at the crown when pulled. 



The injury is betrayed by the wilting and dying of plants over one 

 year old, particularly during dry seasons. 



The only method of control is to starve it out by plowing under the 

 clover immediately after cutting, and this practice should be followed 

 wherever the borer does much damage. 



Blister-beetles. — Swarms of slender, soft-bodied beetles of the shape 

 shown in the figure sometimes eat the potato leaves and prove quite inju- 

 rious. Another species, M. unicolor, was common on peas, beans and 

 vetch. Paris green or lead arsenate will destroy them ; but they should not 

 be killed unless they are actually doing injury, for in their first stages they 

 feed upon eggs of grasshoppers. 



