New Jersey Agricultural Experiment Stations.

Annual report of the New Jersey State Agricultural Experiment Station and the ... Annual report of the New Jersey Agricultural College Experiment Station .. online

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-color, shining, almost hemiBpherical in shape, and on each wing cover,
a little before the middle there is quite a large, dull, orange or blood-
red spot ; from which the insect derives its common name, ^' twice-
stabbed.'' In size it varies from an eighth to three-sixteenths of an
inch in length, and as increased length is also accompanied by
increased breadth and thickness, the largest specimen seems more
than double the size of the smallest In California these insects may
be found active at all seasons of the year, and they feed upon armored
scales in preference; on the Pacific Coast generally preferring the
pernicious soale to almost anything else. In New Jersey this same
insect, which is also a native here, makes its appearance late in April
or early in May, and nothing more is seen of it after the middle of
JSeptember. Although I have made no direct observations, yet from
the dates of the specimens that I have seen, and from the times that
I collected them, two broods of this insect seem to be normal. The
beetle hibernates and appears towards the beginning of May. It lays
^gs, from which larvffi hatch about the tenth of that month or a little
later, and sometime in July a second brood of beetles makes its
appearance from these larva. In August the second brood of larvffi
has been observed, and beetles apparently just issued, were found in
September. It is possible, however, that in the southern part of the
State there may be three annual generations. In California the
number of broods has not been definitely observed; but judging from
what I saw myself, there must be at least six. Such enormous



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622 NEW JERSEY AGEICULTUEA.L COLLEGE

numbers ef specimens as were fonnd everywhere in Califoniia, I
never eaw in New Jersey, and evidently oar climate is a serioos cheek
upon the increase of this species. As the scale breeds with as quite-
as rapidly as it does in California, it is obvioas that this lady-bird can
never be as effective here as it is in the more fiivored State. The egg^
are bright yellow in color, and quite large in proportion to the size of
the beetle. They are elongate-oval in shape, set on end in little groaps^
something like those of the potato beetle, and in a general way
resembling the eggs of other lady-birds, which are not uncommonly
found on leaves infested by plant lice. The larvse are very dark
gray or blackish, spiny, and with a more or less well-marked whitish
or yellowidi transverse band across the middle of the body. This-
mark is quite characteristic and makes it possible to recognize the
insect in this stage with great certainty. The larv» feed preferably
upon active young or recently-set scales, and where they are at all
numerous undoubtedly destroy a great number. When full grown^
the beetle larva atteohes itself to the bark by the anal extremity,,
suspends itself head down, the skin splite, and the pupa wriggles
partially out of it. In this condition it remains for a few days, until
ready to tranform to an adult. This beetle I believe to be the most
effective enemy of the San Joe6 scale in California. Combined with
the Aphdinus, it has done most effective work in the southern
counties, and is, I believe, largely responsible for the decrease of the
scale in that part of the country. Though the species is also native
with us, yet I imported several colonies of the Califomian form in
the hope that the breeding habits acquired in that State might lead
to a more rapid development in New Jersey, and might give U3 at
least one or perhaps two more broods in die course of the season..
Whether this will prove possible or not, is a question.

EXOCHOMUS PILATn Muls.

(The Piute Lady-bird.)

This insect resembles the twice-stabbed lady-bird in general appear-
ance and markings, but is larger, attaining a length of one-quartor of
an inch, and the red spot on the elytra covers a much greater spaoe^
actually and proportionately. It is also set farther forward, and in
some cases touches the base of the wing covers. Instead of having a
tendency to be circular or round, it is nearly always more or less



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EXPERIMENT STATION REPORT. 62$

obloDg or square. The most obvious distinotioiiy however, is in the
size. This insect has been observed feeding npon the San Jos^ scale
in California, of which State it is a native. It is mnch less abundant,
however, than the CkUoeorus, and breeds very much more slowly.
It does not make its appearance until well along in May or June, and
seems to have not more than two, or at most three, broods in the
course of the season. In fact, it acts in California much as the twice-
stabbed does in New Jersey, though it becomes more abundant there
than our species does with us. Some colonies of this insect were also
introduced into our State, and the specimens, when liberated upon a
scale-infested tree, seemed to make themselves at home. An exami-
nation made in early fall, however, failed to detect any trace of them
in any stage.

OBCUS CHA.LYBBU8 Boisd.

(The blue Lady-bird.)

The insect is of a bright blue color, without markings of any kind^
and is therefore easily recognized. It has the general shape of the
twice-stabbed lady-bird, and is about the size of the smaller speci-
mens. It is a member of the same general group to which the CAtVo-
eoru8 belongs, and has much the same habits. It was introduced into
California in 1892, and for a time gave promise of increase, spreading
firom the orchard in which it had originally been placed to several
others in the neighborhood. Great stories were beginning to circulate
concerning its e£Qcienqy on armored scales, but, unfortunately, instead
of continuing to increase, it rather decreased in numbers, and at the
time of my visit in California, was sparsely present only in the
orehard into which it had been originally introduced. It was hoped
that it would increase later in the season, but apparently it did not,
and nothing could be found of it during the latter part of July, when.
an attempt was made to collect colonies for me.

BHIZOBIIDS.

The species belonging to this general series are all small, few of
them as much as one-sixteenth of an inch in length and most of them
much less. They are very convex, but a little oval in outline, and
are black or a little bronzed in color. The surface is more or less
covered with fine silky hair, among which are interspersed longer,.



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€24 NEW JERSEY AGRICULTURAL COLLEGE

brisde-Iike prooesaeB^ irregularly set on the surface. Taken as a
whole, the home of these species is in the southern hemisphere,
although some species are found north of the equator. More are
found, however, in Australia and adjacent countries than elsewhere,
and this r^on is the source of the forms that were introduced into
California. Two species may be found there at the present time, of
which the larger is

BHizoBius YENTBA^Lis Erichson.

(The black Lady-bird.)

This is called ventraUa from the fact that the under side of the body
is largely red in color, in strong contrast to the uniformly black upper
side. The insect is said to be a general scal^feeder ; but practically
it seems to be confined to soft scales in California. Its favorite food
appears to be the black scale, which it attacks in all its stages and to
which it IB undoubtedly a formidable enemy. The exact history of

'the species in California has not yet been worked out ; that is to say,
there is no definite information concerning the number of broods or

^ the amount of food and its kind that will be taken by a beetle or its
larva in the course of its life. It is asserted by Professor Wood-
worth that the insect feeds by preference upon scales that are attacked
by fungous disease, and, if this proves to be the case, its effectiveness

' is limited, since the insects eaten by it would have been killed at any
rate. There is no pretense that this insect has been recognised as an
effective enemy of the San Josi scale, and it was never found by me on
infested trees. The species does not occur at all in many localities
where the scale has been cleared out, and in fact the pernicious scale
had been practically disposed of before Bhizobku ventraUB was intro-
duced into California. No particular effort was made, therefore, to
introduce this species into New Jersey; nevertheless, quite a number
of specimens were brought in with the other material, and these were
liberated in the same way, most of them in the Riverton orchard of
Mr. Edward Lippincott. Some colonies were also sent to Washing-
ton, B. C, to Br. L. O. Howard, and these were freed in the orange-
houses of the United States Bepartment of Agriculture. In August,

-on the occasion of a brief visit to Washington, Br. Howard and
myself carafuUy examined the trees infested by the black scale where
the lady-birds had been liberated; but no trace of them was found

4ind no signs of any feeding upon the black scale.
The second species is



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EXPERIMENT STATION EEPOET. 52^

BHIZOBIUB LOPHANTJE Blaifid.

(The brown-necked Lady-bird )

This insect is maoh smaller than B. verUrcUis, some of the speci-
mens not exceeding one- sixteenth of an inch in length and none of them
becoming quite one-eighth of an inch in the examples before me. The
insect has a mach more shiny appearance and a distinct bronze lucjter^
perhaps caused by the dense clothing of short brown hair with which
it is covered. The thorax, or neck, is of a dull-brown color, which
gives the insect its common name of ^' brown-necked lady- bird.''
The native home of this insect is also Australia and the adjacent
countries, and the date of its introduction into California is uncertain.
It was sent in by Koebele, it is claimed, on the occasion of his first
visit to Australia, when the VedcUia also was introduced, but from •
the fEUsts that less than two years thereafter it was already found in
considerable numbers as far south as San Diego, and also in the San
Gabriel Mountain cations north of Pomona, it is certain that the
species must have been in the country for a considerable number of
years before that time. It is by no means as rapid a breeder as
ventrcUiSf though it is much more active, and seems to have no prefer-
ence for cultivated orchards, occurring quite as abundantly in the
wild lands as anywhere else. This species is unquestionably a scal^
feeder in all its stages, and there is no doubt that it feeds upon the
San Jo€6 scale ; yet from what I saw myself and from what I could
learn from others, it was never abundant enough on infested trees to
have been a factor in reducing this scale. Up to the beginning of
June it was impossible to find larv», and only a few specimens of the
beetle could be obtained here and there. At best, the insect seemed to
be a comparatively rare one in most localities. This was indicated by
the fact that, except for a few in the first sending, none were received
from Santa Barbara, and they never became plentiful enough in the San
Joe6 district at any time during the summer to enable the commis-
sioner to gather colonies to send into New Jersey. It was only at
Pasadena, almost at the foot of the Sierra Madre range, that any
number of specimens were obtainable, and most of the colonies sent
into New Jersey were obtained from that one locality. The orchards
where the species occurred in collectible numbers were all more or
less infested by the red scale, which resembles the San Jo£6 scale quite
closely in size, form and structure, but while the beetles were more or



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€26 NEW JERSEY AGBICULTUEAL COLLEGE

less abuDdanty they did not by any manner of means oontrol even this
red scale, which has but a small fraction of the reproductive power
of the pernicious scale. Neverthdese, this Rhizobiug is the only one
which offers any chance of suocessfal introdaotion into New Jersey.
It has shown its ability to spread by extending over so large a portion
of California withont artificial effort made to distribate it, reaching
from the soathern boundary as far north, at least, as Marysville, and
without doubt beyond and through the whole Sacramento Valley
fruit region. It has shown, in this, a power of adapting itself to
circumstances, and of moving with considerable rapidity withont
being artificially transported from place to place. Therefore, while I
oould hardly feel that the insect would be of any practical use to our
fruit growers as against the San JosS scale, nevertheless it is a species
which, if it becomes domesticated in New Jersey, will be nsefnl
against armored scales in general. Elsewhere I have given a record
of the colonies that were received, and have mentioned the points at
which they were liberated.

The larv» of the Rhizobiids resemble each other in a general way.
They are of a rather light-gray color, a little flattened, quite broadly
oval, without distinct spinous processes, and are rather sluggish in
their movements.

8CYMNIDS.

Closely allied in general size and appearance to the Bhisobiids are
the little species of Soymnus. They have the same general appear-
ance, much the same coloration, or rather lack of oolor, and to the
ontrained eye offer few points of distinction. They are periiaps not
quite so convex as are the Bhizobiids, and seem to be more nearly
circular in outline, or less oval. Like the Ithissobiid$, they are also
clothed with a very fine pubescence or dense hairy vestitnre ; bat this
is applied closer to the body and \b not mixed with stiff, bristly hair.
The surface is also less shiny, and does not seem to have a bronze
reflection; yet it requires a skilled entomologist to discover in all
cases the difference between the two groups. Practically it makes
little difierence to the agriculturist what the minute structural di£br-
cnces between them are. Our Soymnids are largely scale-feeders, yet
we do not know, in most instances, to just what extent they also feed
npon other things. We know that some species attack the ''red
spider ; " that several of them feed principally upon plant lice, and
we do not know positively that more than a very few of them feed
exclusively upon scale insects.



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EXPERIMENT STATION REPORT. 527

In the East, the speoiee of Seynvmu are rather rare, and it is seldom
that any considerable number of specimens of any species can be found.
In California^ where insect life is on the whole much more active^
^several species become quite plentiful, and perhaps the most common is

SCYMNUS MABGiNicoLUS Mann.

(The margined Scymniis.)

This, in its general appearance, resembles Bhizobiua lophantce^ but
it is of a dead black, without the least trace of bronze reflection, and
IS much less convex. The thorax or neck is more or less brown or
reddish, rarely entirely so, but usually with a broad border, leaving
only a central black disk. Specimens occur, however, in which the
teddish color is reduced to a mere line, and in some instances it dis-
4tppears altogether; so the entire insect becomes black. This is the
most abundant form found in California^ and chiefly, if not exclusively,
4imong plant lice. Its resemblance in size and general appearance to
Ehizobius lophankB has caused it to be also taken for Bhizobiua ddMis.
I have already detailed the fact that all the specimens sent into New
Jersey as 22. debilis, are really referable to this spedes, and of the
Oalifomian insects received during the present season, this fonns by
4dl odds the greatest proportion. Unfortunately the complete life
history of this Boytninua is not known, and while it has been asserted
ihat it feeds upon the San Joe6 scale, it is also a fiEust that it is among
plant lice only that it can be collected. I do not know just how far
this spedes is distributed in California ; but all the specimens received
here came from Santa Barbara county, the r^on perhaps least likely
to give us specimens to survive our winters. If they do, we have an
insect that may become useful in dealing with such pests as the melon
plant louse; but we certainly do not have one that can become very
useful in preventing injury by the San Jo66 scale. Dr. Horn, in his
jiotes on the Scymni, gives its range as from a little north of San
J'randsco to the southern boundary of California.

Closely allied to the species of Scymnus is the little

SMiuA (pentilia) mtbwTiTiA Lcc.

(The mlfierable Lady-biid.)

This is a minute species of lady-bird not much more than half the
-size of a San Jo£6 scale, shiny black in color and very broadly oval
in outline. It occurs throughout the United States from the Atlantic



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628 NEW JERSEY AGRICULTUEAL COLLEGE

to the Pacifio Coast and north as far as Canada. It is a typical soale*
feeder^ and of all oar speoies offers the best chance of becoming of
assistance to fruit-growers as against the pernicious scale. It is the-
only speoies observed by me in New Jersey which has become at all
abundant on infested trees, but I have found it this year in every
scaly orchard examined, and in the Biverton orchard of Mr. Edward
Lippincott there are some trees on which it occurred in great numbers
in all stages. It seems to breed almost as long as the scale itself, and
has been recorded from Maryland late in November.'*' Howard and
Marlatt declare that ^' the beetles seem to prefer the full-grown female
scales, and were frequently observed standing astride a scale, almost
on end, pushing their heads under the margin of the protecting scale-
to get at the soft yellow insect beneath.^' The larv» of the beetles
seem to feed more abundantly on the young scales. The tree on which
most of the specimens were found in all stages was that upon which-
most of the introduced insects were liberated in the Lippincott orchard.
In this case a piece of muslin had been tied between the branches so
as to form a sort of platform, and a little above it another piece was
tied to form a roof. The object was to make a sort of shelter for the
insects when first liberated, and to make an examination of the speci-
mens of a sending possible without handling. There was no par-
ticular attempt at neatness, and the material was full of folds and
creases, especially where it was tied to the branches. It was
found in September that the creases in this muslin were filled
with Smilia larvsB ready to pupate ; or, in other words, the insects
sought shelter of some kind when ready to undergo their trans-
formations. Scarcely a pupa could be found elsewhere upon the
tree, but just at this place everything seemed to have oongrq;ated.
Howard and Marlatt record that ^ra favorite place of pupation was
discovered to be within tha calyx of the pears. This cavity is
often literally filled with a mixture of young and old scale
insects, and frequently contained full-grown Pmtilia larv», their
pup» and also freshly-issued beetles.^' It is possible that this
species has some enemy that attacks it while in the helpless pupal
state, and that it requires shelter in order to enable it to multiply
most satisfactorily. It may not be a bad scheme to give the insect
the necessary shelter by loosely tieing around the trunks of infested
trees, above the point of branching, a piece of burlap or sacking, or a

* I have since found it abundantly in Monmouth county in December.



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EXPERIMENT STA.TION REPORT. 529

fetbrio of almost any kind. The fignre herewith given indicates the
appearance of the beetle, its larya and somewhat its relative size, as
compared with the San Jo£6 soale. Usefal as this inseot ondoabtedlj
is, it has the disadvantage of aiding in the spread of the soale. Those
fonnd orawling about in September were almost invariably burdened
with from one to four, or even five, scale larv», which clung to the
surface of the beetle and were carried by it wherever it went. A
flight to an uninfested tree in the near vicinity would serve to at once
stock it with specimens.



Fig. 10.

SmfUa miK&i, in all its stages : a, beetle ; b, larva ; c, papa ; d, blossom end of pear, showings
scales with lanrse and adults of SmUia feeding upon them, and pupae attached within the calyx ;
all greatly enlarged. (From Division of Entomology, U. S. Department of Agriculture.)

Another insect that was found in California^ feeding rather spar*
ingly on scale-infested trees, was OybwyephaltM oalifomious Lee., a
beetle belonging to an entirely different family, the NUidulidcB. The
insects of this family are, as a whole, feeders upon fungi or more or
less decaying vegetable material, yet there seems to be little doubt
that this particular species feeds upon the San JosS scale, and probably
others as well. The insect was found in small numbers at San Joe^,

84



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630 NEW JERSEY AGRICULTURAL COLLEGE

and it is more than likely that where it has been observed it has been
taken for a very small Seymnus, or for the PentUia miseUa, which it
resembles in appearance, bnt than which it is even smaller in size.
As the insect conld hardly be considered a common one, no effort was
made to introdace it into New Jersey.



SUMBiA^BY.

We have no good basis for believing that any of the insects intro-
duced into New Jersey from California, or which can be introdnced
from that State, will become sufficiently abundant in a measurably
short time to be of use in keeping the pernicious scale in check. The
two species which have done the most effective work in California are
already natives of New Jersey and require no introduction. Climatic
differences make them less effective with us than they are on the
Pacific Coast. We can probably count that both the Aphelinu8 and
the CMlooorua will in time become increasingly abundant Our most
active species is Smilia {PentUia) miaellay which thus far offers the best
chance of an effective enemy. We cannot hope, however, that it will
increase sufficiently to become an important aid for a considerable
number of years to come, and it does not seem as if our fruit -g^wers
could afford to wait for this or the other species to increase without
taking active measures for the destruction of the scale.



DISEASES OF THE SCALE.

The pernicious scale, like all other insects, is more or less subject
to disease. There is every reason to believe that disease has been an
important agent in destroying the scale in many parts of California.
It is reported that in some localities in Florida disease has almost
exterminated it. It is reported from Maryland that there seemed a
lack of vitality in the larv» at one period during the summer when
examination was made, similar to what I observed in California in
May and June. Nothing like a real disease has yet been discovered
on the scale of New Jersey, but there is no reason to believe it will
be more fortunate here than it has been elsewhere, and we may expect
that in the near future some natural check of this kind will moderate
its progress. None of the diseases have yet been studied sufficiently



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EXPERIMENT STATION REPORT. 531

9

to enable us to aay what they really are^ nor can we^ thus far, propa*
^te them. This line of research is by no means abandoned, how-
•ever, and studies are being made with the object of discovering what
•diseases attack the scale and which, if any of them, can be propa-
^ted artificially and used for inocnlating the specimens on the trees.
This is a branch of the case that can only be mentioned here, at
present, as being ander consideration. It will remain for the futoxe
4o decide what we can do in this direction.



ItECORD OF INSECTS INTRODUCED INTO NEW

JERSEY.

AJthoagh the observations made in California do not promise well
for the saccess of natural enemies in dealing with the scale in New
Jersey, it was nevertheless deemed advisable to do all that was pos-
sible to get into the State such species as offered even a remote chance
of being beneficial.

It is well established that, in parts of southern California, the per-
nicious scale began to lessen in number in 1889, and was already well
•under control in 1890 and 1891. Hhizobiua veniraiiSj B. debUis, and
the species of Orcua were not introduced until 1892, hence they could
not possibly have had any influence on previous occurrences. BhizO'
inu8 lophardcB or towoombce was already well distributed at that time
in California ; probably from some accidental importation long before
Koebele sent it from Australia in 1890, on his first trip. It was not
rare in the caflons of the San Gabriel range, north of Pomona, in 1891,



Online LibraryNew Jersey Agricultural Experiment StationsAnnual report of the New Jersey State Agricultural Experiment Station and the ... Annual report of the New Jersey Agricultural College Experiment Station .. → online text (page 43 of 45)