THE SUGAR-BEET WIRE WORM. 
{Limonius californicus Mannh.) 
HISTORICAL. 
The sugar-beet wireworm (Limonius californicus Mannh.) has been 
known in the coast lowlands of southern California for many years, 
having been more or less destructive to sugar beets during the time 
they have been grown here, and prior to that time was known as an 
alfalfa and corn pest. In many locahties the alfalfa had to be 
plowed up and replanted every few years, as the ravages of this larva 
so thinned it out that only a partial crop could be harvested unless 
replanting was resorted to at intervals. Owing to the fact that the 
ground in the alfalfa fields is nearly always damp to the surface, the 
wireworms seldom worked deep, and wliile they tunnelled through 
the crown of the plant, it was only a chance injury or a heavy infesta- 
tion that could make itself felt, so that its destructive powers in the 
alfalfa fields is proof enough of its abundance. 
The wireworm has also been noted as a corn pest for years, many 
growers reporting that on occasions it has been impossible to secure 
an average crop even with several plantings. Mr. Nelson Ward, of 
Compton, reports that on puUing up cornstalks he has discovered 
from 17 to 30 wireworms burrowing through the roots and into the 
crown of a single plant. 
LOSSES DUE TO THE SUGAR-BEET WIREWORM. 
There is great variation in the estimates of losses ascribed to this 
insect, and very probably the correct estimate would run far above 
the others. The reason for tliis is that unless the injury is excep- 
tional it is likely to go entirely unnoticed. When the wireworms 
work scatteringly, their injury is apparent only to the observer who 
is looking especially for it, and at the right time. The writer bases 
this assertion on observations made during the early spring of 1912. 
At this time the adults were being collected, and as several hundred 
acres of beet fields were carefully gone over several times, it was 
possible, by close observation, to get a good estimate of the progress 
of the injury and the total damage done. 
The sugar beets were quite small, having just been tliinned, and 
were consequently at just the right age to receive the greatest injury. 
The roots were simple, not having swelled, and wherever a beet plant 
was attacked it was generally killed, as the roots were almost invari- 
ably severed by the feeding of the wireworms. All the plants which 
were noted wilting down were examined, and always with the same 
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