BULLETIN NO. 41.
A FUNGUS DISEASE
THE SAN JOSE SCALE
(SShaerostilbe coccophila, Tul)
P. H. ROLFS.
The Bulletins of this Station will be sent Free to any address
in Florida upon application to the Director of the Ex-
periment Station, Lake City, Fla.
DE LAND, FLA.
B. O. PAINTER & CO.,
BOARD OF TRUSTEES.
HON. WALTER GWYNN, President... ...... ... .Sanford
HON. F. E. HARRIS, Chairman Executive Committee.... Ocala
HON. A. B. HAGEN, Secretary............... ... Lake City
HON. S. STRINGER .... ............ .. ... .... Brooksville
HON. H. W. GELSTON... ... ...... ... ... ... ...DeLand
HON. WM. FISHER ... ....... ...... ... .. ....Pensacola
HON. F. L. REES... ...... ......... ... ... ...Live Oak
O. CLUTE, M. S., LL. D ................... ....Director
P. H. ROLFS, M. S......... ... .Horticulturist and Biologist
A. A. PERSONS, M. S......... ......... ...... Chemist
J. P. DAVIES, B. S............... Assistant in Chemistry
A. L. QUAINTANCE, M. S........... ... Assistant in Biology
JOHN F. MITCHELL. ...... ... ..Foreman of Lake City Farm
J. T. STUBBS ......... Supt. Sub-Station, DeFuniak Springs
W. A. MARSH. ... ... ...... ... Supt. Sub-Station, Myers
W. P. JERNIGAN, .... ............. Auditor and Book-keeper
LIBRARIAN ... ..... .. ... ... ... ...... ... Lake City
Title page. ................ ...... ..... . 513
Board of Trustees... .................... .. ...... .... ... 515
Station staff... ...... ............ ... ... ... .. ....... 515
Summary... .................. ... ... .. . ..... .... .. 518
Introduction... ............... .. ... ... .. ... ... ... .. 519
Disease of the Cabbage Worm... ...... ........ ............ 520
Chinch Bug Disease... ... ... ... .. ......... .. ......5 520
Points to be Considered.. .... ....... .. .... .. ........5 520
Imported Insects ..... .... ........ ... .. ........... ...522
Search for the Natural Cause... ...................... .....5 522
The Natural Cause Found........ ..... ..... ........ .. ... 524
Distribution of the Fungus..................... ............. 525
Artificial Dissemination... ............. .. ... .. ... .... 526
By Means of Diseased Scales ... ............... ............ 526
By Means of Spores Grown in the Laboratory...... ........... 527
The Media ............ ...... ... ... .. .. ..... ... .... 527
Experim ents... .............. ... ...... ............ ... ... 528
Experiment No. 1.. ...... ......... ... .. ...... ..... 529
Experiment No. 2... ... ......... ...... ... ...... ...... 529
Experiment No. 3... ............... ........... ........ 529
Experiment No. 4... .................. ............... ...529
Experiment No. 5... ...... ....... ...... ......... ... ... 529
Experiment No. 6... ... ... ... ... ... ... ... ...... ... ... 529
Experiment No. 7... ... ... ...... ... ... ... ... ... ... ... 530
Experiment No. 8... ...... ...... ... ......... ........ 530
General Remarks................... ................ ........ 530
Biology... .................. ......... ......... ...... ... 531
Adaptability of this Fungus......... .................. ....... 535
Acknowledgments... ............ ...... .................... 535
Explanation of Plate I... ............ .... ... .............. 538
Tlate I ...................................... ........
Explanation of Plate II... ...... .... .......... ............ 541
T late II . ............... .. ... .
1 It has been definitely established that insects are subject to
2. Diseases of insects have been, and are being employed to
destroy insect pests.
3. Some diseases of insect pests may be disseminated arti-
ficially with a profit.
4. This disease of the San Jose Scale is present on at least three
continents and in many countries. In several instances it is re-
corded as an important factor in controlling scale insects.
5. It is doubtless native to Florida as it occurs on a native
scale (Aspidotus obscurus) in our hammocks.
6. This fungus may be transferred to trees affected with San Jose
Scale and a disease produced -among the sales.
7. Large quantities of material may be produced in the laborato-
ry in a short time and at slight expense.
8. The laboratory-grown material may be applied successfully
by fruit growers.
9. This fungus cleared the orchards more efectively of San Jose
Scale than could have been done by many sprayings.
10. It is now being tested in the North and West.
A Disease of the San Jose Scale.
A close study into the members of the insect world has
revealed the fact that they often suffer with maladies that sweep
away their members by myriads. The expression that the
climate is not suited to a certain species of insect is quite co m-
mon and usuallyaccepted as final, butit only states our ignorance
of the true state of affairs; it is simply an admission that we do
not know the specific factor that workers against the increase of
a certain species. Closer study on this subject has revealed the
fact that insects are the prey of many and varied organisms.
The first important advance in the study of insect diseases
was made by Dr. Louis Pasteur, an agricultural scientist of
Paris. The silk industry of Europe in 1870 amounted to more
than a hundred million dollars. The greater portion of this was
produced in France, but in a few years the output in that country
was reduced to half the normal proportions by a disease of the
silk worm known to the French as flacherie. The working of
this disease was very mysterious and could not be explained
easily. Pasteur began the study on this malady under many
difficulties but finally succeeded in proving that it was due to a
bacterium. After learning what the real cause of the disease was
it became quite easy to suggest measures for its prevention.
Pasteur proved that the disease could be transmitted from sick
silk worms to well ones and that when well ones were brought
into the breeding cases where sick ones had been kept, they
would become diseasd. The discovery was so different from
anything then known by the agricultural people of France that
it required frequent public demonstrations of the fact before it.
was generally accepted. This was accomplished in such a mas-
terly manner that Dr. Pasteur received special recognition from
the French government.
DISEASES OF THE CABBAGE WORM.
In December, 1883, Prof. Forbes, of Illinois State Univer-
sity, delivered an address to the Illinois State Horticultural
Society in which he gave an account of work in his laboratory
with a disease of the cabbabe worm (Piers rapae), Prof. Forbes'
object being just the opposite of Dr. Pasteur's. Prof. Forbes had
proven very clearly that a disease occurred among cabbage
worms and that this could be disseminated artificially among
these insects (Trans. Ill. Hort. Soc. Vol. 17, P. 29.) After it
was settled that this was a contagious disease, it was sent to the
neighboring State of Iowa. Prof. Osborn, Entomologist of the
Iowa Agricultural College, infected a cabbage field with it and
has found that it reappears in successive years and that it has
been an important, factor in keeping down this insect.
CHINCH BUG DISEASE.
The chinch bugs are often exceedingly destructive in the
grain fields of the North-West and West. Often entire grain
crops are destroyed and even the corn crops severely injured. A
disease has been discovered among these and several entomol-
ogists have interested themselves disseminating it and collecting
evidence from the persons to whom the material has been sent.
Chancellor Snow, of the Kansas University, has been especially
active in this line and has met with the most flattering success.
Prof. Forbes, of Illinois State University, has also worked on this
chinch bug disease, and has had good success. Prof. Osborn, of
Iowa Agricultural College, has also given this matter careful at-
tention, as has also Prof. Lugger, of Minnesota State University.
Prof. Webster, of Ohio State University, has disseminated the
chinch bug disease in grain fields of Ohio, but it has not been
so successful in that State.
POINTS TO BE CONSIDERED.
Several points must be taken into consideration before at-
tempting to introduce such disease among insects. First, we
must have some germ that finds the particular insect vulnerable
to its attack. The germ that causes the disease among cabbage
worms, before mentioned, does not attack chinch bugs nor does
the chinch bug disease attack the cabbage worms. It is plain,
therefore, that we must have a particular germ to cause disease
of particular insect. Second, the insect must have such habits as
will expose them to the attack of that germ. As long as the
chinch bugs are not abundant enough to congregate, the disease
makes slow progress. This same disease attacks other insect but
fails to destroy many of them because these insects do not con-
gregate in large numbers. The disease of the cabbage worm
could not spread rapidly among chinch bugs because the disease
enters the body of its hosts (the cabbage worm) with its food.
The bacteria lodging on the surfaceof the food plant are eaten by
the cabbage worm and then set up a disturbance in the digestive
system of the insect. Chinch bugs obtain their food by sucking
the juice from the interior of the plant which normally contains
no bacteria. Third, the atmospheric conditions must be favor-
able. A warm, moist atmosphere is excellent for the propaga-
tion of the chinch bug disease while a dry and a cold atmosphere
does not allow it to germinate and grow rapidly. We see, there-
fore, that the combatting of insects, by means of their diseases,
is circumscribed by strict laws, each one of which must be ful-
filled or all our efforts are without effective results.
One would conclude, on first thought, that the fulfilling of
all these conditions is a very exceptional occurrence, but that
these conditions occur frequently is evident from the fact that
although insects increase with marvelous rapidity, they rarely
cause great devastation. We are all familiar with the great
locust incursion into States of the Missouri valley, but this insect
was not able to hold its acquired territory for more than two
years. The heavy rains killed eggs, nymps and adults. Diseases
of various kinds came in to destroy myriads. The journey of the
Colorado potato beetle east of the Mississippi is also fresh in our
minds. Although there seems to be no general or wholesale
destructive disease of this beetle, its enemies have so reduced its
number that it rarely becomes destructive. This is Nature's own
way of equalizing and distributing to each species its own
Insects introduced from other countries are often very
destructive and spread with great rapidity. As we have seen in
the case of the Horn Fly, which was introduced from France in
about 1886, and became very destructive along the Atlantic coast
of the United States, reaching Florida in 1891 (cf. Bulletin 17,
P. 14, Fla. Experiment Station). The white fly, or mealy wing
(Aleyrodes citri), the fluted scale (Icerya purchase), and San Jose'
scale (Aspidiotus permciosus), are all examples with which we
are familiar. Many of us are familiar with one or more of them
at a considerable expense. All of these insects will doubtless run
their course in time and become only one of the myriads of
species that prey upon the products of the soil. Just how much
destructive work these pests will do before they are successfully
counteracted by "natural causes" is impossible to say. In some
cases they would doubtless destroy entire industries and thus
limit their increase by cutting off their own food. Happily we
can bridge the period by artificial means such as fumigation,
spraying, etc. In this way we help nature to strike a balance.
Prof. Webber has shown that nature is already setting up a
reaction against the increase of the mealy wing (Aleyrodes citri).
At the ninth meeting of the Florida State Horticultural Society,
in Jacksonville, he exhibited a parasitic disease of this insect that
he had found at Braidentown, (cf. P. 73, Proc. Fla. State Hort.
Soc. 1896.) This fungus was exceedingly active in reducing the
numbers of the mealy wing. It was a most fortunate discovery for
the orange grower as the dissemination of this disease in the
groves affected with sooty mould will prove a great economic
factor in producing bright oranges. (See also Bulletin No. 13,
Div. V. P. & V. P., U. S. Dept. Agri., by H. J. Webber).
SEARCH FOR THE NATURAL CAUSE.
During June, 1895, on a visit to the orchards affected with
San Jose' Scale, at DeFuniak, there were strong indications in
some places that the scale was less severe than it had been. A
diligent search in several orchards did not reveal any "natural
cause" for the diminution of the scale. A return to several
orchards in May, 1896, proved that the former suspicion was
well founded, so a strenous effort was made to find this "natural
cause" that was operating on the scales. Some fruit growers
suggested that it was the freeze of '94 and '95, but that could not
be since the scale flourishes in States where the temperature goes
below zero. Others suggested that it was the mild weather; that
could not be the cause since the scale is quite at home a hundred
miles farther south. Others suggested the recent drouth, but
dry weather is favorable to the multiplication of this scale. As
we had not had a rainy season that year this was not suggested.
Inquiries were made of Mr. Geo. Mellish of orchards that were
isolated and that were badly infested two years before and had
not been sprayed, nor treated in any other way with a view of
killing the scale. After two days' patient searching an orchard
was found on the farm of Mr. A. C. Bailey. This orchard con-
sisted of peaches and plums and was on cleared hammock with
hammock adjoining. After looking about in the orchard for a
short time we discovered that the trees which were badly infested
two years ago were now entirely free from scale except that here
and there where there were dead limbs with an abundance of
dried scales, showing beyond the slightest doubt that these trees
had been infested with this scale. It was not difficult to find dead
scales in such a state of preservation that they could be distin-
guished from the allied species (A juglans-regiea, Cons.) so
common in this section. Mr. Bailey could point out many trees
that had been severely affected. Our remembrance of the matter
was thatthe wholeorchard was infested and manytrees were con-
sidered too badly affected to be worth spraying. On referring
to notes taken two years before (cf. P. 94, Bulletin 29, Fla. Agri.
7x. Sta., also P. 19, Bulletin No. 3, N. S. Div. Ento. U. S. D. A.
by L. O. Howard), they were found to place this orchard among
those that were badly infested. The most remarkable thing
about the whole matter was that we were not able to find a single
live scale on the trees that we were examining. This was the
more astonishing since all the artificial methods employed in
Florida were not able to so completely destroy the ,scale without
killing the tree. In Florida the most thorough and repeated
application of insecticides have failed to eradicate the insect when
once firmly established.
THE NATURAL CAUSE FOUND.
Mr. Bailey was asked finally, if all the trees were free from
scales, whereupon, we were taken to four or five that were still
affected, with the result that diseased scales in great abundance
were found on each tree. In every case where San Jose' Scale
was found in this orchard we also found this fungus attacking it.
To the botanist it is known as Spaerostilbe coccophila, Tul. The
ordinary observer would overlook it entirely as the largest speci-
mens are not over one-eighth inch high, though after it had been
pointed out to the orchardists they had no trouble in discovering
it in other trees.
Dr. L. O. Howard on page 54, Bulletin 3, N. S. Div. Ento-
mology, U. S. D. A. (1896) makes the following quotation from
Bulletin 26, by D. W. Coquillett, of the Division of Entomology,
U. S. D. A. (1892), "A few weeks ago Mr. C. H. Richardson, of
Pasadena, one of the county inspectors of fruit pests, showed wm.
several pear trees in that locality which a year ago were very.
thickly infested with these scales, as was evidenced by the
gnarled appearance of the branches as well as by the dry scales
still adhering to the trees. After a careful examination of these
scales scarcely a live one could be found. Mr. Richardson as-
sured me that the trees had not been treated with any kind of
insecticide and they certainly gave no sif:is of such treatment.
The dead scales gave no signs of having been destroyed by lady
birds, nor yet by internal parasites. Wishing to ascertain if this
singular mortality was general in other localities, I examined
several infested pear trees in this city, but found that the fruit
and new growth upon them were thickly infested with scales,
which were alive and to all appearance in a very thriving condi-
tion. It would appear therefore, that the mortality among the
San Jose' Scales was entirely due to some low form of fungus
growth." In a later paragraph Dr. Howard states, "We have
therefore, recently (1896) secured through the kindness of Mr.
John Scott, Horticultural Commissioner of Los Angeles county,
Cal., a considerable quantity of dead and dying scales supposedly
affected with this disease. Mr. A. F. Woods has conducted a
careful examination of the material, at the instance of Mr. Gallo-
way, to whom we referred it, and while the conclusions so far
reached are not sufficient upon which to base a definite recom.
mendation, there seems to be a specific disease which develops
both in the insect and its covering." There is nothing in the
papers at hand to show that the California disease is not the same
as this one.
DISTRIBUTION OF THE FUNGUS.
This is the first time that this fungus has been reported as
causing a disease of the San Jose' Scale, though it enjoys a .wle
distribution. It has been collected on three continents at least
and in each case it causes a disease among scale insects.
M. C. Cook in his Vegetable Wasps and Plant Worms, pub-
lished in London in 1892, calls this fungus, Coccus tubercles, and
gives the following, excellent popular description: "This well
known parasite on dead coccus is not uncommon in Europe, and
has been found several times in Britain. They form little rosy
knobs, with a short, whitish velvet stem-like base. Sometimes it
is 'conical and sometimes it is club shaped and rather hard and
horny when dry. The whole mass is composed. of parallel
hyaline delicate threads, densely compacted together, bearing at
the apex very long curved conidia, spores, which are acute at
each extremity, and with three or five septa or divisions (but
sometimes with evidently more), from seventy [70-25,ooo inch]
to one hundred micromillimetres [Ioo-25,ooo inch] long and five
[5-25,ooo inch] thick. It is supposed to be the conidia stage of
some more perfect fungus, but at present this is merely a sup-
position (plate 2, Fig. 22). The bright red spots on dead cocci
are recognizable by the naked eye."
Mr. Henry Tryon, entomologist to Queensland, Dept. Agrl.
Oct., 1894, Bulletin No. 4, page 15 says: The Red Scale, the
Circular Black Scale, and the Long Mussel Scale, were again
frequently killed by another parasite, Microcera coccophila,
[Sphaenostilbe coccophila, Tul.] reproductive organs of which
could commonly be observed as small compact scarlet masses
emerging and ascending from their edges.
Prof. T. D. A. Cockerell records this fungus from Jamaica
as occurring on Aspidiotus articulatus, a scale infesting citrus
trees. (cf. Bull. Bot. Dep., Jamaica, Oct. 1892.)
Messrs. Ellis and Everhart, in North American Pyrenomy-
cetes, page III, say that this fungus has been collected in South
Carolina by Ravenel and in Florida by Dr. Martin.
It is a common disease of Aspidiotus obscurus Coms.. It
was first discovered on this insect by Mr. A. L. Quaintance in
November, 1896. Subsequently it has been found in great abun-
dance in a number of locations. It was'also found by myself in
February, 1896 on oaks planted in the streets of DeFuniak, Fla.
From the foregoing facts it is quite reasonable to suppose that
it is quite generally distributed throughout Florida and the
South, and not impossible that it has found its way to California,
but definite information on that point is not at hand. It seems
quite certain that it is a native to Florida, and from its wide dis-
tribution among the native scale, A. obscurus, Coms. This fact
makes it the more interesting and valuable as a remedy against
the San Jose' Scale.
BY MEANS OF DISEASED SCALES. The next most
important point, after finding a disease of great dis-
tructiveness, is to discover how it may be dissemi-
nated by artificial means. A test of this was made immediately
after the fungus had been discovered. Some branches containing
diseased insects were cut from Mr. Bailey's plum trees and
were taken by Mr. Geo. Mellish and tied into trees affected with
San Jose' Scale. The orchard belonging to Mr. Mellish was en-
tirely free from disease of San Jose' Scale and several miles from
Mr. Bailey's orchard. Six weeks later the orchard belonging to
Mr. Mellish was visited and it was found that the disease of the
insects had spread to a considerable distance in the tree to which
it had been transferred. The orange colored prominences could
be detected on many scales within eighteen or twenty inches of
the infested stick that had been brought from Mr. Bailey's
orchard and stick had not yet lost its virtue.
This test decided the matter beyond reasonable doubt that
the disease could be disseminated by carrying sick scales from
one orchard to another and also that it may be carried for long
distance and used with good effect.
The operation is very simple. It may be stated briefly as
follows: Select a branch of any tree holding San Jose' Scales
affected with the disease; cut off a piece, eight, ten or twelve
inches long; tie this piece firmly to the upper side of a limb in-
fested with San Jose Scale, so that the two will lie parellel; and
in contact for as great a portion of their length as possible. This
is a certain and practical method of starting the scale disease in
BY MEANS OF SPORES GROWN IN THE LABORATORY.-It is
a well established fact that it is possible to grow various moulds,
bacteria and otherorganisms in the laboratory, uponmaterial free
from all other organisms than the particular one that is being
studied. Organisms grown in such pure cultures may be studied
to best advantage; in fact a botanist cannot do work in the study
of animal and plant diseasesof scientific merit and worthy of pop-
ular confidence unless he studies with pure cultures. It is neces-
sary to have special apparatus, a laboratory, and to follow certain
definite rules to produce a pure culture. This is no greater feat
to the mycologist, however, than it is for the horticulturist to
grow a pure variety of tomatoes. It is not- necessary to go into
detailed discussion of this matter, but we should keep it in mind
clearly, that a pure culture of this fungus contains but one
organism, and that the specific cause of the death of this scale.
Immediately upon.arriving at the laboratory steps were taken
to obtain pure cultures of this fungus. The first step was to pre-
pare sterile culture media. As it was a matter of experimentation
to learn upon which this fungus would thrive best, a considerable
number of different medias were prepared. Acid, alkaline and
neutral agars; acid, alkaline and neutral gelatins; sterile potato;
acid, alkaline and neutral bread were experimented with.
The acid agar proved to be the best of that group and the
alkaline the poorest. The acid gelatine was better than any of
the agars and the best of the gelatine group, while the alkaline
gelatine was the poorest of that group. Sterile potatoes pro-
duced a good growth and a 'moderate quantity of spores. Of all
the media tried, slightly acid bread proved the most successful
and produced spores in greatest abundance: The fungus grew
readily on slightly alkaline bread and better on neutral bread but
thefinest growthand greatest abundanceof spores were produced
as stated before, on slightly acid bread. Bread being porus, the
fungus permeates the whole piece and produces myriads of
spores in the pores, thus adding greatly to the spore producing
surface of the medium. The spores germinate readily in distilled
water, but of course, cannot do more than this. After germina-
tion the spores and mycelium remain vital for a few days and
then become sterile.
As soon as practicable a quantity of spores were grown in
the laboratory to be used in the field for artificial infection. Six
four-inch petrie dishes of acid bread were inoculated from pure
cultures and in three weeks these were taken to the field and the
spores applied to various trees infested with San Jose' and other
scales. A piece of bread about an inch square from a petrie dish
was placed into a quart of water and shaken until the bread was
broken up and the spores evenly distributed in the water. This
was then applied to the scaley tree by means of a sponge or cloth
or sprayed on.
Experiments one to five were located in an orchard belong-
ing to Mr. John Astleford. This orchard is a considerable dis-
tance from others and the San Jose' Scale were not severe except
on individual trees. The insects were spreading rapidly showing
that they were having a healthy growth.
7, 1xperimnent No. I.-A plum tree sprayed twice with spores
of this. fngus prepared by placing some of the infected bread in
a quart of water. The first application was in the afternoon and
the second just before dark, July 29, 1896. A portion of the tree
was then wrapped with a moist gunny sack.
Result.-February 20, 1897. Scales thoroughly inoculated.
The disease having spread to many branches.
Remark.-The idea of wrapping moistened burlap or other
cloth loosely about the treated limbs is well worth following out.
It is a question of only a few hours whether the spores are to
produce the disease or whether they will die. If a moist atmos-
phere prevails all is well and good, if drouth, the spores will die.
The reason for this is brought out strongly in the study of the
biology of this fungus, so it will not be stated here.
Experiment No. 2.-A peach tree in good condition, except
severely infested with San Jose' Scale, which seemed perfectly
healthy, was sprinkled late in the afternoon of July 29, 1896 with
material similar to that used in experiment No. I.
Result.-February 20, 1897. Insects not affected. No trace
Experiment No. 3.-A peach tree like the one in experiment
No. 2, sprinkled July 29, 1896, with material similar to that used
in Experiment No. I.
Result.-February 27, 1897. Insects all dead.
Experiment No. 4.-A peach tree like the one in Experi-
ment No. 2, sprinkled, July 29, 1896, with material similar to
that used in Experiment No. I.
Result.-February 27, 1897. Insects not affected. No trace
Experiment No. 5.-A peach tree a considerable distance
from No. 2, but conditions very similar to the one in Experi-
ment No. 2, sprinkled later in the evening, July 29, 1896, with
material similar to that used in Experiment No. I.
Result.-February 20, 1897. A large proportion of the in-
sects dead and peeling off. The disease well disseminated
throughout the tree.
Experiment No. 6.-A peach tree in an orchard near De-
Funiak Springs belonging to Mr. G. E. Mellish, severely infested
with San Jose' Scale was sprinkled, July 28, 1896, with material
prepared as that used in Experiment No. I. This tree showed
signs of having been infested for a long time.
Result.-February 20, 1897. Scales all dead.
Experiment No. 7.-A tree under conditions similar to the
one in Experiment No. 6. .Sprinkled with material prepared as
in Experiment No. I.
Result.-February 20, 1897. Tree dead.
Remark.-The death of the tree cannot be attributed to the
fungus. Microscopic examinations show that the fungus does
not pierce the bark.
Experiment No. 8.-A quantity of the material was left
with Mr. Geo. Hollowell, DeFuniak, Fla., who applied it to scaly
trees much as described in the foregoing experiments, dur-
ing latter part of July, 1896.
Result.-February 20, 1897. No infection could be dis-
I. The conditions for the application of this material were
adverse at the time inasmuch as a dry spell followed the applica-
2. The best time to apply the material is after sundown on
a moist evening; this condition may be produced artificially see
remark, Experiment I.
2. The spores raised on bread germinate in a few hours
and must find a suitable medium in which they may grow (E. g.;
San Jose' Scale) or they will perish.
4. The spores produced in the orange colored protuber-
ance (See plate I, figure i) seen on scales live for several months
in dry weather.
5. That so many of th experiments turned out favorably
substantiate our former expectations that the material might be
6. The material can be produced in great quantities and its
application to the insects is as easily accomplished as a .single
spraying with insecticide.
7. It is more thorough than insecticides.
8. While it is "Nature's own remedy" for striking a bal-
ance in Florida, it will doubtless be less effective in dryer
9. It will be noticed that the cooperation of orchardists
has been secured in making the initial tests, proving that the
laboratory grown material is effective in their hands and that the
orchardist who may not be a scientist can apply it properly.
o1. Further experiments will perfect the methods of apply-
II. The fact that this fungus is widely disseminated on a
native scale insures a constant source of new material, thus
avoiding the necessity of using any that may have become
12. The fungus 'multiplies many fold more rapidly than the
San Jose' Scale.
13. As soon as the insects have been killed rains wash the
fungus and dead scales from the trees leaving no signs of the
tree having been diseased except where the scales may have in-
jured the tree.
A San Jose' Scale attacked by this fungus is usually trans-
formed into a mass of mycelia before there is any exterior ap-
pearance of a change. When the body of the insect has been
consumed a bright orange colored protuberance forms at the
base of the scale or at times it breaks through the protecting
cover of the insect. This orange colored protuberance is the
most conspicuous part of the fungus and the only portion visible
to the unaided eye; these vary in size from an eighth to a fortieth
of an inch.
Those that measure about a sixteenth of an inch are the
most abundant under favorable conditions. Figure 3, plate II
represents a cross section of a scale insect and the spore bearing
protuberance magnified twenty-five diameters. The outlines of
this figure were drawn by the use of a camera lucida. These
spore bearing bodies may be seen in figure I plate I, as small
projections, enlarged less than two diameters. These small pro-
jections contain a great many spores, represented by figure 6,
Plate II (enlarged 120 diameters). These spores, under favorable
circumstances, mature within six weeks from the time of infec-
tion. Countless numbers are liberated from the orange colored
protuberances during rains, and are washed down the trees and
some to the ground.
If a moist atmosphere continues for several hours these
spores will germinate and produce sporidia, represented
by figure 7, a, which at maturity, may be carried about in the
atmosphere. In case the spores represented by figure 6 find
lodgment in a place suitable for further growth a sporidium, re-
presented by figure o1, is produced. Under favorable condi-
tions, sporidia germinate in the course of three or four hours,
otherwise they retain their vitality for only a few days.
These sporidia, represented by figure 7 a, on germinating in
a situation where there is only a slight amount of nutriment for
this fungus, produce a growth represented by figure 14. Figure
14 a represents the original sporidium which germinated and
produced the larger mycelium, after which the branches b, c, d,
e and f were successively produced. Consecutively with e and f,
g and h were produced; then followed i and k. While g, h, i and
k are morphologically aborted branches of the mycelium, they
finally become enclosed in a wall and later are detached to per-
form .functions similar to those of a sporidium. The production
of the spore-like bodies, g, h, i and k marks a cessation of vegeta-
tive activity. These spore-like bodies, g, h, i and k have the
power to germinate even in distilled water, but produce a
mycelium that is not more than two or three times the length of
the diameter of the spore-like bodies. If, however, the medium
in which it is grown contains a sufficient amount of nutriment,
vegetation goes on freely, and a fungus plant may result as in
case of germination of a sporidium.
If a sporidium be placed in a slightly stronger nutrient
solution, growth represented by figure 15 takes place. In figure
15 a represents the secondary spore, and b a spore-like body
produced after considerable growth of the myceium had taken
place. This spore-like body may be formed directly from the
secondary spore or from the mycelium and may be liberated be-
fore other spore-like bodies are produced, or before the
mycelium has ceased to grow. In other respects the body repre-
sented by figure 15 a is similar to figure 14 g.
If a sporidium is transferred to strong liquid nutrient me-
dium germination takes place in a few hours and a much
stronger mycelium is produced. Finally, by the production of
spores and continued vegetation a dense felty mass is produced.
Figure 16 represents a branch of the mycelium producing spores.
Under these conditions spores are borne on sterigmata, a, b, c,
d, e, f and g which were produced in succession as lettered. At
h, is represented the beginning of a sterigma. These spores are
produced one at a time and when fully formed may be. detached
by a slight jar, but if handled carefully they may remain attached
loosely until as high as four have been formed when the forma-
tion of a fifth will detach one or more of the older ones. Some
sterigmata produce more spores than others that seem to have
equal advantages; some remain sterile (16 d). Spores produced
in this way retain the power to germinate for nearly a month
in a humid atmosphere, but lost it after remaining in a dry
atmosphere for only a few hours.
In connection with these spores a very interesting phenom-
enon occurs. The mycelium seems to have a power of inhibit-
ing the growth of spores produced in this way. In cell cultures
great many spores collect near the mycelium, but do not ger-
minate; when the same spores were removed only a fraction of
an inch from the mycelium many of them germinated; and when
they were removed to the other edge of the hanging drop, the
normal proportion germinated.
The growth of such spores placed in distilled water is repre-
sented by figures II, 12 and 13, in successive stages of develop-
ment. Figure 13 represents the original spore, ii, enlarged into
a rudimentary mycelium, which has divided into two cells and
produced a spore-like body at lower end which is similar to
figure 14 g.
At intervals on the mycelium such as represented by figure
16, hyphae are produced that protrude from the medium in
which it is growing. The successive stages of these hyphae are
represented by figures 17, 18, 19 and 2o. The length of these to
the spore bearing portion varies with the depth of the medium
in which it is growing. It is apparent from the beginning that
such a branch as represented by figure 17 has some special func-
tion to perform. Gravity seems to havy no influence'upon the
direction, but it seems to take the direction of at least distance
to atmosphere. By comparing it will be noticed that these
hyphae bear sterigmata, similar to those in figure 16, which bear
a number of sphaerical spores; the first one formed, or the one
at the distal end, is the largest. These spores are easily dis-
lodged, and are much slower to germinate than the spores
represented by figure 16.
Figure 25 represents a very interesting form taken by the
mycelium at times. In the beginning the mycelium does not
seem.to differ from the ordinary forms, but in the courses of four
or five days this is changed into a necklace-like form represented
by figure 25 a. A second portion of the mycelium, figure 25 b,
has become much enlarged. This enlarged portion, 25 c, then
produces spore-like bodies which germinate when they become
detached, figure 25 d. After these spore-like bodies become de-
tached more of a similar character may be formed.
Spores of this fungus were placed on agar gelatine, on live
San Jose' Scale and on live obscure scale (A. obscurus) in culture
cells. In these cases the spores developed in quite a different
* way from all but those represented by figuge 20. Figure 21
represents a young hypha. Figure 22 shows a hypha further
developed. Figure 23 shows the sterigmata, also the beginning
of sphaerical spores. Figure 24 represents a hypha at maturity.
In a dry atmosphere these spores separate easily and may be
carried about by the wind; in a moist atmosphere they cling
together in chains. These spores have been kept for several days
in a dry atmosphere without loosing their vitality. If twigs con-
taining scale insects attacked by this fungus be placed in a moist
chamber this kind of spores is produced in such quantity that
they become visible to the unaided eye, making the insect appear
as if covered with a minute blue mold. Pure cultures may be ob-
tained with greatest ease by using these spores.
Such spores as are represented in figure 16 (with figures II,
12 and 13) were sown in distilled water where they germinated
.in a few hours. At the end of twenty-four hours the mycelium
had grown to eight or ten times thelength of a spore. After about
forty-eight hours further growth ceased. A very peculiar phe-
nomena was noticed repeatedly: Spores under these conditions
germinated in a short time and grew rapidly for about twelve
hours, thengrewmore and moreslowly untiltheir full growthwas
reached in about forty-eight hours. During the early portion of
growth the mycelia took independent courses, but later the end
of 26 a bent towards 26 b, with which it united. In this case 26 b
seemed to be benefitted by the union. This second mycelium
then grew out to 26 c with which to unite, which in turn received
support from 26 b. As this occurred repeatedly it is difficult to
resist the conclusion that there is some affinity between these
different mycelia in distilled water. The mycelum of this fungus
does not, as a rule, anastosmose in a nutrient media.
ADAPTABILITY OF THIS FUNGUS.
From the foregoing study into the biology of this fungus,
we learn that it has an unusual ability to adapt itself to the
various conditions which may surround it. The stage repre-
sented by figure I, plate I, enables it to pass through long
periods of drouth and long periods of cold. The stage repre-
sented by figure 16 occurs during the rainy season and is not
confined, in its growth, to insects but may occur on other media.
The spores represented by figures 20 and 24, occur
during moist periods and greatly facilitate the multiplication and
thorough dissemination. When periods of drouth or cold
weather occur, the fungus is carried over such periods by means
of the spores represented at figure 6. These spores usually lodge
in such places as are not most favorable to the development of
the fungus, so a sporidium, represented by 7 a, is produced,
which may be carried about in the atmosphere. In case this
lodges in an unfavorable place for the further growth of the
fungus, a spore-like body that may be called a secondary
sporidium, represented by figures 14 g, 14 h, 14 i, 14 k and 15 b,
is produced, which in turn may be carried about in the atmos-
I am pleased to have this opportunity to express my appre-
ciation of the special favors received from Dr. Wm. Trelease in
the use of the extensive library in the Missouri-Botanical Garden
and the library and well equipped laboratory of Washington
University. The final work on the biology of the fungus and
figures 3 to 23, 25 and 27 were done at the laboratory of the
I must also thank Dr. Roland Thaxter for so kindly deter-
mining the specific name of this and other fungi for me.
Explanation of Plate I.
Figure 1. Spaerostilba coccophila, Tul. on Aspidiotus perniciosus,
Coms. from an artificial inoculation on a peach tree. (Slightly en-
Figure 2. Cultures of Sphaerostilbe cocophila on bread. A por-
tion of this culture was used to induce the infection photographed
for figure 1. (Natural size.)
PLATE I.-Figure 2.
Explanation of Plate II.
Figure 3.* Cross section Sphaerostilbe stroma and San Jose' scale.
Figure 4.* Small conidium spore germinating.
Figure 5. Larger conidium spore germinating.
Figure 6. A large conidium spore.
Figure 7. A conidium spore germinating from a second cell.
Figure 8. Large conidium spore germinating from both ends.
The middle cell has not discharged its contents.
Figure 9. Further development of No. 8.
Figure 10. Sporidium completed.
Figure 11. Spore taken from figure 16 and placed in distilled
Figure 12. Development of 11.
Figure 13. Development of 11 completed and spore-like body
Figure 14. Sporidium placed in a slightly nutrient media.
b. First branch of the mycelium.
c. Second branch of the mycelium.
d. Third branch of the mycelium.
e. Mycelium from sporidium.
f. Mycelium from sporidium.
g, h, i and k. Spore-like bodies.
Figure 15.* Sporidium in medium containing more nutriment.
b. Spore-like body.
Figure 16. Sporidium germinated in standard nutrient media.
a, b, c, d, e, f and g. Sterigmata.
Figure 17. Hypha grown in liquid media.
Figure 18. Hypha further advanced.
Figure 19. Hypha still further advanced.
Figure 20. Hypha with mature spores.
Figure 21. Hypha grown in solid media.
Figure 22. Hypha further advanced.
Figure 23. Hypha still further advanced.
Figure 24. Hypha bearing mature spores.
Figure 25. Growth in media.
a. Necklace form of mycelium.
b. Enlarged mycelium.
c. Spore-like body.
d. Spore-like body germinated.
Figure 26. Spores with anastosmosing mycelium.
a. b and c, original spores.
Figure 27.* Conidia spores attached to branching basidia.
*Figure 3 enlarged 25 diameters.
Figure 4 to 14 and 16 to 26 inclusive enlarged 130 diameters.
Figures 15 and 27, 240 diameters.
S 12I. i8
21. 22 2