18 COMMON WHITE GRUBS. 
winter quarters beyond the reach of the plow. Ordinarily the best 
time to plow is between October 1 and October 15. Jn 1913 deep 
plowing at.any time in the fall, especially in early fall, will be of 
special value in those regions where the grubs were so destructive in 
1912, since the grubs will then have changed to pupe and adult 
beetles, and these will be destroyed if the pupal cells in which they 
pass the winter are disturbed. 
ROTATION OF CROPS. 
Since the beetles usually deposit their eggs in fields of grass, tim- 
othy, and small grains, the crops planted in these fields the year fol- 
lowing a season of beetle abundance should be those which are the 
least susceptible to grub injury, such as small grains, buckwheat, 
clover, alfalfa, and peas. Care should. always be exercised.in the 
selection of a crop to follow sod or old timothy ground, even though 
the beetles were not noticed as especially abundant the preceding 
year. Where hogs can be pastured on the land the fall or spring 
previous to planting, as discussed in another paragraph, the grubs 
will be practically eliminated. 
COLLECTING THE GRUBS AND BEETLES. 
Where it is possible to secure cheap labor, collecting the grubs after 
the plow is practicable, especially where the grubs are numerous. In 
Europe children are often employed to gather grubs in this manner 
and to collect the beetles as described below. 
Collecting the cockchafer or Maikiifer, a beetle very closely related 
to the May beetle, is a common practice in European countries, but 
so far as known the attempt to collect May beetles on an extensive 
scale in the United States has never been made. Three methods may 
be employed in beetle destruction: (1) Collecting from plants upon 
which they feed at night, (2) trapping at lights, and (3) poisoning 
their food plants. 
In Europe beetle collecting has proved of value largely because 
the years of abundance of the beetles have been definitely known in 
advance, while in America this has not been the case. Now, however, 
there is proof that the beetles occurring in such abundance in many 
parts of the United States in 1911 (the parents of the destructive 
generation of grubs in 1912) have a life cycle of three years, and it 
is reasonably certain that they will continue to be exceptionallye 
xbundant in these regions every. three years unless killed off by their 
natural enemies, by artificial means, or by unfavorable climatic con- 
ditions. Beetle collecting in the Old World has also proved prac- _ 
ticable, first, because of the organized cooperative movement by the 
farmers for the collection of the beetles; second, because a small 
bounty is paid for the beetles; and, third, because of laws which in 
some countries require each farmer to collect a certain quantity of the 
grubs or beetles each year. Individual action is useless, and only 
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