12 THE SUGAB-BEET WIRE WORM. 
result, viz, the tender taproot was cut and blackened and a search 
generally revealed the offender, a wireworm, in the soil near by. A 
great amount of just such work was noted, but it differed from that 
of 1911 in that it was more scattered. 
In 1911 the wireworms seemed to be working in groups, and many 
spots of varying size were completely cleared of beets. In 1912, 
however, the fields were almost entirely free from this type of work. 
Places were observed where from three to six beet plants had been 
Idlled in one group, but by the time the beets are mature their foliage 
so covers the ground that all trace of the injury is lost to the casual 
observer. One incident will illustrate this point. A small beet field 
of 10 acres located near the laboratory was carefully watched that 
some idea might be gained of the progress and time of injury. Every 
day many of the plants were found dead, but seldom were more than 
three or four plants killed in a place. While this injiry was con- 
siderable it was kept well scattered. At the time of the last examina- 
tion the beets, then nearly ripe, so covered the ground with their 
foUage that even where several adjoining plants had been killed it 
was difficult to find any signs of the injury. This shows that it is 
an easy matter to overlook the destructive power of this wireworm. 
The sugar-beet wireworm may be considered the worst insect 
enemy of the sugar beet in southern California at the present time. 
It has this distinction for two reasons : First, it is constant, appearing 
every year to a greater or less extent; and, second, its injury occurs 
in such a manner that replanting is generally impracticable, or at 
least of little value. While beets and alfalfa appear to be the favorite 
food plants, the sugar-beet wireworm is also very injurious to corn 
i^g. 3, p. 18) and beans (Pis. VI, VII). 
It would be a difficult matter to figure the loss due to the wire- 
worm, either in percentage of the crop, tons, or dollars, but an 
approximation will show its importance economically. Mr. E,. S. 
Vaile, horticultural commissioner of Ventura County, in his annual 
report for 1912, places the loss to lima beans alone in his county at 
$10,000. For 1913 he estimates the loss at $25,000 or more. If 
the other counties where this wireworm is destructive are taken 
into consideration it will be seen that probably the lima-bean growers 
alone lose at least $50,000 a year by this insect. Add to this the loss 
to sugar beets, which is probably even greater, and it is readily seen 
that this wireworm presents no small problem in southern California. 
INSECTS FOUND WITH THE SUGAR-BEET WIREWORM. 
Collections of wireworms in the beet fields of southern CaUfornia 
show at a glance that they are made up of several species. These 
differ widely in appearance, hence there is little chance of their being 
mistaken for one another. Two of them, Limonius californicus Mannh. 
and Drasterius livens Lee, are of the waxy color usually found in 
