26 THE SUGAK-BEET WIEEWORM. 
ACTIVITY OF THE ^YIREAVORMS. 
During the spring, when the soil is kept wet by the rains and loose 
by cultivation, it is probable that the wu-eworms are able to travel 
from one beet plant to another. Under laboratory conditions they 
have been noted to travel several inches daily, in the root cages, and 
the soil then is Terj apt to be compacted b}' wettmg. This pomt 
was tested by placing several ^\m'eworms in a root cage ^^'ithout food 
in order to compel them to move. The soil, which was quite damp 
at first, was allowed to become pretty thorougiily dry, and then the 
cage was watered. The water followed the channels of the vdre- 
worms, and in this wa}^ the wheworms could be easily traced by the 
wet streaks through the soil. These cages were 18 by 24 mches, yet 
in the week or 10 days the soil was drymg out the ^ii'eworms had 
been able to channel all thi^ough the soil. Late m the summer, vrhen 
the soil is more dry and compact, the}' move about much more 
slowly and are less anxious to feed, but as the}^ do all thek damage 
in the spring their actions at the latter time are of the utm^ost mipor- 
tance. From all the observations on their activity it seems not only 
possible but even probable that one wireworm can destroy several 
young beet plants in a season. The sugar-beet plants are from 6 to 
8 inches apart in the rows. 
WIEEWORM INJURY TO BEETS. 
Durmg the latter part of February and m March and April the 
ravages of the ^Ti'eworms in the beet fields are very noticeable, 
especially so when the insects are present in numbers. In a year 
such as 1912, when their work was well scattered, injury can be 
noted, but it is possible to overlook it. 
When the young beet plants are attacked thej wilt, and upon 
examhmtion the root is found to be either badly scarred or entirely 
severed. (PL IX.) This injuiy generally takes place between 1 and 
4 inches below the surface. There are two general types of mjury; 
in one the taproot is cut off clean, and the beet wilts and dies (see 
PL X) ; m the other the ^\Ti^eworm, after eatmg mto the root, turns 
and descends, eating off a side of the root as it goes down (see 
PL IX). This, of course, scars the root badly, and if the beet is 
quite young and tender it is apt to die. If, however, the beet is 
quite strong and the root is swollen a little, so that the mjur}' does 
not cut off the sap suppty, it will recover, though always remaining 
distorted and undersized. (See PL XL) 
In years when the wireworms appear hi numbers they are likely 
to be concentrated m certam spots. T\lien this occurs they kill 
off all the beet plants in these areas, causmg the characteristic 
''bald spots." (Pis. XII-XV.) ^Yhell once they have collected in 
