INSECT ENEMIES OF WESTERN FORESTS 25 
The large, shining, brown “June bugs” (fig. 10) often lay their 
eges in grassy places or where the ground vegetation 1s heavy. In 
the North, where the life cycle is 3 or more years in length, the small 
white grubs feed during the first summer on organic material and 
on small rootlets near the surface of the soil. As cold weather ap- 
proaches they burrow more deeply into the soil and hibernate. ‘The 
second season the grubs are larger and do their greatest damage to 
the roots of seedlings and small trees. They again hibernate over the 
second winter and again feed during the following spring. ‘The full- 
grown grubs are white, thick-bodied, with dark-brown heads and 
three pairs of well-developed legs. They always le in a tightly 
curled position and are familiar ob- 
jects to everyone who has dug for fish 
bait. In midsummer of usually the 
third season they reach full growth, 
transform to the pupal stage within a 
cell in the ground, and emerge the fol- 
lowing spring as full-grown beetles. 
In the Southern States the cycle may 
be completed in 2 years, or possibly 
less, while in the North and in Canada 
it may take 3, 4, or even 5 years. 
The prevention of white grub dam- 
age can be accomplished to a great 
extent through modification of cul- 
tural operations. New ground that is 
to be used for nursery purposes should 
be put under cultivation for 2 or 3 
years to allow for the emergence of 
beetles already in the ground and to 
avoid new egg laying. 
If transplant beds are cultivated 
frequently in the seasons when they 
are lying fallow, and these periods of 
Figure 10.—Adult beetle, eggs, and 
resting are interspersed between the larva or white grub of Polyphylla 
period of use, the damage by white ee ae 
grubs will usually be comparatively 
light. Infestation in seedbeds is likely to give the most trouble, since 
the dense growth produces a favorable condition for egg laying, and 
the beds cannot be cultivated until the seedlings are taken up. Beds 
can be protected by covering them with a 14-inch mesh wire screen 
during the egg-laying period. If the beds become infested, the young 
seedlings should be dug the second spring to avoid heavy damage. 
Clean cultivation, screening of seedbeds, and rotation of transplant 
beds are first steps in holding white grub damage to a minimum, but 
even these are not always successful. 
Seedbeds which must be repeatedly used may become heavily in- 
fested. Recent experiments have indicated that the grubs can be 
killed by the use of 50-percent miscible carbon disulphide. A satis- 
factory dosage consists of 1 quart of the miscible carbon disulphide to 
50 gallons of water and an application of 3 pints of the emulsion to 
each square foot of soil surface. Care should be taken not to allow 
any of the solution to come in contact with the leaves of the young 
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