LIFE HISTORY AND HABITS. 27 



this mannei- and have cleared ofl" the l)eets it is ahnost hnpossible 

 to raise beets there (hirino^ tliat yeai-, even if i-eplanting is resorted 

 to several tunes, as the wii'ewornis kill them as soon as they germinate. 



The injury caused by the wireworms is characteristic and should 

 never be mistaken. In the first place, if the injury is recent, an 

 examination will 2-eveal the wireworm near by in the soil. If no 

 wireworm is present an examination of the wound will readily show 

 whether or not it is wireworm injury. The wound itself is stained 

 black, as if rubbed with ink. Sometimes the black stain has pene- 

 trated for a short distance into the sound beet tissue, but where it 

 has not, it is considerably darker than the dry tissue surrounding an 

 ordinary old wound. 



Eifect of overflowing on the wireworm. — From the fact that mre- 

 worni injury is often noticed in fields which have been overflowed 

 in the latter part of the winter, it has naturally been supposed that 

 overflowing of the land is favorable to wireworms. This has not 

 been proven to be entirely true. A careful watch was kept on the 

 fields which are subject to overflow, and from these observations 

 it seems that overflowing the land is of account only as it affects 

 the character of the soil and is therefore secondary. In overflowed 

 land which tends to be sandy the wii'eworms are likely to be destruc- 

 tive year after year. On the other hand, flooded land which is a 

 heavy silt and rich in humus is seldom so badly injured as is sandy 

 unflooded land. One thing has been noticed, however, and that 

 is that flooding the land does not seem to injure the insect in the 

 least and therefore gives little promise as a control measure. Some 

 of the beet fields which have suffered the most durmg the last few 

 years are those which almost every year are quite thoroughly flooded 

 for two or three days. 



TIME THE WIREWORMS CAN LIVE WITHOUT FOOD. 



Wliether or not these larvae are able to find food in the soil is hard 

 to determine, but judging from the length of time they are able to 

 Live without food it seems possible that they do receive some suste- 

 nance from the soil, ])robably in the form of decaying vegetation. 

 This is further borne out by the fact that where larvae are kept for 

 a time in a cage without food all the lumps of leaf mold disappear 

 and the soil in the cage becomes homogeneous. 



Several observers have reported that these larvae can survive long 

 periods without food, and one example which was noted in the 

 laboratory will furnish added proof. During June, 1910, Mr. H. M. 

 Russell commenced a starvation experiment by placing several 

 wireworms in a root cage, with ordmary soil, without food. In 

 July, 1911, seven larvae were still alive and healthy. This cage was 



