Among these are the black
beetles which feed on cutworms and other larvae which injure the roots
of plants. Lady-bird beetles destroy large numbers of plant-lice, and
the Asiatic lady-bird has been found to be the natural destroyer of the
San Jose scale. These little insects are now being hatched in this
country, and it is hoped through them to stamp out the pest. A number of
larger insects prey on the smaller ones.

Other insects, such as the Hessian fly, the green-bug or spring grain
aphis, the army-worm and various species of grasshoppers are killed by
tiny parasitic insects whose eggs are laid in the bodies of the larger
insects, but which, after being hatched, feed on them.

To these natural methods of control man has added others. Cultivation is
one of these methods. As insects flourish when given an unusually large
amount of food of a particular kind, and starve when that food is taken
away from them, so rotation of crops proves to be one of the best means
of getting rid of those insects which can not travel far for their food.
Farmers who practise rotation of crops are much less troubled with
insects that injure the roots of plants than those who do not.

One of the best means of preventing damage from the Hessian fly is to
sow a narrow strip of wheat all around the edges of the field several
weeks before the main crop is to be sowed. The flies will gather in
this strip and lay all their eggs in the early wheat. Just before the
main crop is sowed, the narrow strip is plowed up and thoroughly
harrowed and the larvae perish for want of food.

The best known means of getting rid of grasshoppers is to destroy the
eggs. This should be done by plowing and harrowing all roadsides, ditch
banks, uncultivated fields and grassy margins around fields in the fall
or winter.

Fall harrowing and deep spring plowing will prevent many of the bugs and
beetles which spend the larval state in the ground from hatching. This
method will also destroy the plum-curculio in orchards.

In attempting to control the boll-weevil of the cotton fields, it has
been found that the best method to pursue is the simple one of planting
the crop very early, so that the cotton passes the danger stage before
the insects emerge, and removing all the plants in the fall.

Worms that infest fruit can be checked for the following year by fall
plowing in the orchard and by destroying the decayed fruit as it falls.
The farmer who lets his decayed fruit