The =Common Dart= or =Turnip Moth= (_Agrotis segetum_ or _A.
clavis_).—_Moth_ (Fig. 99): Length almost ⅘ of an inch. Span of wing
about 1⅘ inch. Fore wings small, ash-grey or brownish, with many dark
patches and similar markings. Hind wings in the male, bright grey to
snowy white; in the female, brownish grey. _Caterpillar_ (Fig. 99): Up
to two inches, earthy grey, occasionally somewhat greenish. Head and
prothorax darker. The time taken by the caterpillars to complete their
development differs according to the plants attacked, and it is
therefore easy to understand why the moths should be seen flying about
from the first half of May right on into the autumn, without having
recourse to the improbable hypothesis of two successive generations. The
eggs are consequently laid at very different times, and are always
deposited singly in the soil in the neighbourhood of plant roots, or
else in the low-lying leaves and stems of various herbs. The
caterpillars hatched from these are destructive earlier or later,
according to the time of egg-laying. Most specimens are half grown in
winter; these continue their destructive work the following spring. In
autumn they attack the roots of winter grain (rye and wheat), rape, and
species of cabbage; they also bore readily into turnips and potatoes. In
spring, after the winter rest, they continue to attack the roots of
winter grain, winter rape, etc., or fleshy underground parts (turnips,
potatoes) developed in the interim, or the roots of summer plants
(summer grain, buckwheat, summer rape, vegetables, etc.). On clear days
the caterpillars always remain hidden in the soil; and those which have
bored into juicy underground parts of plants (turnips, carrots), do not
leave their abode during the day, but the others, both during the night
and on cloudy days, come above ground to attack the leaves and stems of
young plants. In exceptional cases the caterpillar is mature by the
beginning of winter, in which case it hybernates in the soil as a brown
pupa. The moths escaping from such pupæ naturally appear earlier than
others. As a rule, the caterpillars do most damage to the winter crop in
autumn, wandering about a great deal; in many cases they gnaw through
the main root, thus quickly killing the plant attacked, from which they
proceed to another. _Remedies_: When the caterpillars have done much
damage in late summer, it is recommended to leave the field alone till
October, then to plough it up and sow the winter grain. By putting off
the seed-time in this way, the caterpillars will have lost their
activity when the corn germinates, and the winter crop will thus escape
them. Besides this, the preceding ploughing will bring many caterpillars
to the surface, where they will become the prey of birds, or, if not,
can be collected. Warm soils, especially those manured with horse dung,
are most infested by the caterpillars; and the use of warm kinds of
manure should, therefore, be avoided in regions which have much to fear
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