The Topeka state journal. [volume] (Topeka, Kansas) 1892-1980, 1907-05-07
THE GREEN BIG.


entomoIogists that the green bug, like
he is usually so few in number that we
do not notice him. Under certain con-
ditions, however, he breeds very rapid
ly, and then his ravages in the grain
fields become apparent. This is the
third time that he is known to have
become serious in this country since
his supposed importation into the
United States.
Mr.. F. NJ. webster. who has charge
of the cereal and forage plant insect
investigation of the United States de-
partment of agriculture, has prepared
a circular about the green bug, and
the subject Is also commented on in
the May number of the Van Norden
Magazine. Mr.. Webster shows con-
clusively that the green bug becomes
a pest after just such mild winters and
cold springs as the present one.
1.-The pest seems to be rather erratic
in its outbreaks in both Europe and
America" says Mr.. Webster. ITO the
agriculturist 1t suddenly appears in
immense swarms on the grain in the
fields in spring, ruins the crop over
large areas Of country, and does not
reappear in destructive numbers. per-
however, that it can be found in the
grain fields during any year through
out the region It fnfests, although 1t
may not be sufficiently abundant to
work serious injury. The extreme
rapidfty with which this insect multi
plies, unless restrained by natural
checks, gives color to the farmers
belief in its sudden appearance, for
within a few weeks. from numbers too
few to be readily noticeable 1t Will de-
velop myriads that swarm over the
green plants, turning whole fields OF
thrifty grain to brown. dwarfed plants
that produce no heads, or else, reach
ing a height of not more than six or
eight inches, have heads that are fore
shortened and nearly devoid OF kerr
nels Thus it is that within the short
space of less than twenty years this
aphis has come to be one of the worst
pests of its kind in the grain fields of
the south central portion Of our coun-
try
The green bug has some natural IN
sect enemies that under normal cir
cumstances keep them down in num-
bers Notwithstanding their rapid IN
crease. Toward the last of May ana
in early June both young and old are
devoured by Iady-beetles and their
larvae. great numbers of which may
he. found in infested fields. Another
small four-winged black fly that is
hvmenopterous parasite forces its eggs
into the bodies of the green bugs and
the development of these eggs into IN
scots results in the wholesale destruc-
ton of the bugs.
The green bugs hardness to cold,
ON the one hand, and the ravages of
his enemies on the other, are two OPP
posing influences that have much to
do in determining whether these IN
sects are to be serious pests or not
The weather seems to determine be- |
tween them. Mr.. webster has con- |
c1uded that these natural enemies or
dinariIy destroy such large numbers
as to hold them in check; also that |
the abundance of the insects that prey |
on the green bug Is primarily regu- |
lated by the weather conditions be- |
tween November and May.
1.-THE situation, then, is probably +
this" continues Mr.. Webster: THE |
pest is kept down by its natural |
enemies, but during open winters
not sufficiently mild, however, to rem
der these enemies active-it breeds |
and the exceptionally |
cold, wet spring enables it to continue |
breeding while the parasites are still |
inactive; thus the pest is enabled to
get the advantage in point of num-
bers and work its devastation before
the natural enemies can become suf
abundant to overcome it.
but the outlook is by no means
the gloomy one that may appear from
this statement. Following the spring
rains there usually comes, sooner or
later, a period of dry, warm weather,
and whenever such a period comes
the aphides very soon disappear. The
reason for this is that their parasites I
and natural enemies, no longer de-
TERED from activity by cold and wet,
begin to breed with ex-
rapidity and bring about
their practical destruction. Should
this warm, dry period come later than
usual, greater damage is inflicted by
the aphides; should 1t come earlier
than usual, serious injury is CORE
spondingly obviated.'