Los Angeles herald., 1891-09-09
APHIS BRASSlCE.
An Enemy Found to the
Sugar Beet.
A Pest Never Before Found in
California.
Some of the Features of the Rascally
Insect.
1t Makes Its Appearance at Alvarado-
What Professor Harkness Has to
Say of It-Its Home Is on
the Cabbage.

Two new lnBeCUS LDdU I66u upOu bHo
leaf of the beet have made their ap-
pearance in the beet-raising districts of
this state. Neither has appeared in very
alarming quantities, and no very great
evil results are expected from them,
says the San Francisco Chronicle of
Monday.
The first and most dangerous of these
bugs is the Aphis Brassic@. Specimens
of this pest were sent to DR.. Harkness,
of the academy of sciences of this city,
for examination and Identification. This
particular aphis has never before ap-
peared in California, though in Belgium
and other parts of Europe they have at
times appeared in great quantities,
causing much damage to the beets.
The specimens sent to this city came
from Alvarado, where they have ap-
peared in occasional patches through
out the beet fields. Wherever they
have appeared, write DR.. Harkness's
informants, they have reduced the sugar
yield of the plant attacked very materi-
ally.
The same pest has been noted recently
by beet-growers at Monterey, and they
TOO have sent specimens to DIR. Hark-
ness. These were turned over to Prof
Behr for analysis.
"The aphis brassice," says the pro-
fessor, twas first discovered on the cab
bage, but takes quite naturally to other
vegetables. 1t is near relative to the
common green aphis, which is found
very commonly on rose bushes. 1t is
much smaller than the green aphis,
though, and may be distinguished
from it by its gray color. The aphis is
known In Europe, Asia, Australia and
America, and seems to be indigenous to
no particular country or locality. 1t
feeds on nearly every herbaceous plant
known. Ten years ago an aphis very
similar to the aphis brassice appeared
in the wheat fields of California in over
whelming quantities and did great
damage to the wheat crop.
"At that time the pest was caused by
the extreme moist temperature. For
two or three months there had been an
excess of moisture in the air and the
heat was sultry and oppressive. When
it became dry again the wheat aphis
disappeared. Undoubtedly, the appear
ance OF the aphis brassicee is due to
the extreme humidity of the atmosphere
this season, and have every reason to
believe that when the weather mends
and California gets back her accustomed
climate the beet-growers will have no
further trouble.
"For the parasite of the aphis that
devastated the wheat fields we searched
long and diligently, but could find none.
But the parasite of the aphis brassice
hoo Log -.
acarid, genus of the mite family. The
aphis has an interesting history. Most
of them have no wings, and are of the
female sex only. They give birth to a
numerous progeny of similar wingless
or fifteen generations throughout the
summer, all of the young insects being
born alive. But the last generation of
females in the fall does not bring it's
young into the world alive. 1t LAYS
eggs, and these hibernate through the
winter until the spring, when the winged
aphis are born. They are the first gem
Grafton, and the only ones that have
wings. All their progeny are females
and wingless. OF course, of the first
generation it is only the males that are
winged"
The other insect submitted to the
academy by the beet-growers is closely
related to the mite and belongs to the
arachnides or spider genus and to the
subdivision of acarines. which includes
maggots, etc. Most mites are carnivor-
GUS and Professor Behr thinks it. quite
likely that the specimens sent to him
may turn out to be parasites of the
aphis brassic@. The specimens submit
ted, however, suffered considerable mu-
tilation from mailing and reached here
in such a condition as to preclude proper
analysis.
"Fhe animal must be studied" said
Professor Behr, from the locality in
which it is found. There good speci-
mems can be obtained and the habits of
the living insect studied to better ad-
vantage. 1t may be, as the beet grow
ers fear, that this insect joius with the
aphis in destroying the leaf, as some
few species of the mites are herbaceous.
| hardly think so, however, leaning to
the belief that the specimens submitted
are of the carnivorous species, in which
case they will be exceedingly useful in
destroying the aphis, for in natural his
tory, as in war and politics the enemy
of an enemy is always an ally.'
Both the insects are exceedingly min
ute and can only be observed to ad-