• TABLE OF CONTENTS
HIDE
 Title Page
 Credits
 Summary
 Table of Contents
 Favorable conditions in Florid...
 Scale fungi do not attack...
 Care necessary for success
 Time necessary to secure infec...
 A private enterprise
 The experiment station cannot supply...
 The red-headed fungus
 The white-headed fungus
 The black fungus
 The yellow fungus of the white...
 The red fungus of the whitefly
 The brown fungus of the whitef...
 Reference






Group Title: Bulletin - University of Florida. Agricultural Experiment Stations ; No. 94
Title: Fungus diseases of scale insects and whitefly
CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00027210/00001
 Material Information
Title: Fungus diseases of scale insects and whitefly
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Physical Description: 17 p. : ill. ; 23 cm.
Language: English
Creator: Rolfs, P. H ( Peter Henry ), 1865-1944
Fawcett, H. S ( Howard Samuel ), b. 1877
Publisher: Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1908
 Subjects
Subject: Citrus whitefly -- Control -- Florida   ( lcsh )
Scale insects -- Control -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Bibliography: p. 17.
Statement of Responsibility: by P.H. Rolfs and H.S. Fawcett.
General Note: Cover title.
Funding: Bulletin (University of Florida. Agricultural Experiment Station)
 Record Information
Bibliographic ID: UF00027210
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: aleph - 000921800
oclc - 18160018
notis - AEN2268

Table of Contents
    Title Page
        Page 1
    Credits
        Page 2
    Summary
        Page 3
    Table of Contents
        Page 4
    Favorable conditions in Florida
        Page 5
    Scale fungi do not attack trees
        Page 5
    Care necessary for success
        Page 6
    Time necessary to secure infection
        Page 7
    A private enterprise
        Page 7
    The experiment station cannot supply fungi
        Page 7
    The red-headed fungus
        Page 8
        Page 9
        Page 10
    The white-headed fungus
        Page 11
        Page 12
    The black fungus
        Page 13
    The yellow fungus of the whitefly
        Page 14
    The red fungus of the whitefly
        Page 15
    The brown fungus of the whitefly
        Page 16
    Reference
        Page 17
Full Text

BULLETIN NO. 94.


Florida
Agricultural Experiment Station.



FUNGUS DISEASES OF SCALE

INSECTS AND WHITEFLY.


P. H. ROLFS


BY
and H.


S. FAWCETT.


Fig. 1. The remedy applied.


The bulletins of this Station will be sent free to any address in
Florida upon application to the Director of the Experiment Station,
Gainesville, Fla.


The Record Co.. St. Augustine, Fla


JULY, 1908.

















BOARD OF CONTROL.
N. P. BRYAN, Chairman, Jacksonville, Fla.
P. K. YONGE, Pensacola, Fla.
T. B. KING, Arcadia, Fla.
J. C. BAISDEN, Live Oak, Fla.
E. L. WARTMANN, Citra, Fla.

STATION STAFF.
P. H. ROLFS, M. S., Director.
A. W. BLAIR, A. M., Chemist.
JOHN M. SCOTT, B. S., Animal Industrialist.
E. W. BERGER, PH. D., Entomologist.
H. S. FAWCETT, M. S., Plant Pathologist.
E. J. MACY, B. S., Assistant Chemist.
B. F. FLOYD, A. M., Assistant Plant Physiologist.
R. Y. WINTERS, B. S., Assistant in Botany.
*R. N. WILSON, A. B., Assistant Chemist.
JOHN BELLING, B. Sc., Assistant in Horticulture
MRS. E. W. BERGER, Librarian.
K. H. GRAHAM, Auditor and Bookkeeper.
M. CREWS, Farm Foreman.
ALFRED DICKINSON, Gardener.


*Temporary Assistant.


















SUMMARY.


1. The climate of Florida is especially favorable to the development
of fungus diseases of insects.
2. The peculiar life habits of scale insects and whitefly larvae make
them especially liable to attacks of fungus diseases.
3. Treating orchard pests by means of their diseases is the natural
method, and hence the desirable one.
4. Spraying to reduce the number of scale insects is recommended for
small and badly infested trees, or for older trees that have
been greatly neglected.
5. To be able to use the natural method successfully we must study
nature and follow nature's teaching. It is not a good method
for the careless or slothful person to rely upon.
6. The six fungi discussed in this bulletin have been known for years
and used successfully, but we had to obey nature's laws in
order to succeed.
7. The Experiment Station is unfortunately financially unable to
supply fungus material, but this can be obtained from private
parties. (See list on page 7.)



















CONTENTS.
PAGE
Favorable Conditions in Florida ............................... 5
Scale Fungi Do Not Attack Trees ............. . .. ... 5
Care Necessary for Success ............. .................. 6
Time Necessary to Secure Infection ......................... .
A Private Enterprise ..................... ................. 7
The Experiment Station Cannot Supply Fungi................. 7
Where Fungi May Be Bought....................... 7
The Red-headed Fungus .................................. 8
Species of Insects Infected ................... 10
How to Apply the Fungus......... ............ 10
The W hite-headed Fungus ......................... ...... 11
Species of Insects Infected ........................... 12
How to Apply the Fungus....................... ... 12
The Black Fungus ...................................... 13
Scale Insects Attacked .............................. 14
How to Apply the Fungus .......................... 14
The Yellow Fungus of the Whitefly. ...... ...... .......... 14
How to Apply the Fungus ....................... 14
The Red Fungus of the Whitefly .................... ....... 15
How to Apply the Fungus ..... .............. .. 15;
The Brown Fungus of the Whitefly.................... ..... 16
How to Apply the Fungus ............................ 16
References ............................ ................. 17










FUNGUS DISEASES OF

SCALE INSECTS AND WHITEFLY.



BY P. H. ROLFS AND H. S. FAWCETT.



FAVORABLE CONDITIONS IN FLORIDA.
Nowhere else in the world have fungus diseases been employed to
combat scale insects and similar pests to so large an extent as in Flor-
ida. This is largely due to the fact that our climatic conditions are
especially favorable to the spread of fungi. In an arid or semi-arid
region to use these species as natural enemies for combating our pests
would be entirely in vain. It happens however that Florida, in addi-
tion to having an abundant rainfall, has also a moist atmosphere.
The use of fungi and bacteria to produce diseases of insects has
been advocated from time to time as a means of repressing these pests.
The conditions, however, under which many species of insects live are
such as to make it a difficult matter to apply the remedy. Wherever
insects occur that are gregarious in their habits, the disease method of
combating them can be used with advantage. This has been repeatedly
proved by the success that has been attained in destroying the chinch-
bug of the wheat fields and corn fields of the Northwest. While the
climate there is ordinarily too dry to permit fungi to flourish, the
wheat plants and corn plants in their growth give off enough moisture
to make the atmosphere in the fields a rather moist one. It thus hap-
pens that rather unnaturally we have a moist condition in a field
situated in what is usually a dry region.
Many species of scale insects and similar insects in Florida suffer
great annual diminution from fungus diseases. This can be readily
proved by simply treating a scale-infested plant with a fungicide, such
as Bordeaux mixture, which will then destroy the fungi that kill scale
insects, and a great increase of the latter will ensue. That there are
still many undiscovered species of fungus which attack these forms of
insects is clearly shown by the fact that within the last year three
species of fungi have been found to attack the whitefly, which hereto-
fore had not been known to be enemies of this pest.

SCALE FUNGI DO NOT ATTACK TREES.
It is frequently asked whether it is not dangerous to introduce these
fungi into an orchard, the questioner fearing that when introduced
they might produce a disease of the trees, or attack the fruit. No such
dangers need be anticipated from any of the scale-destroying fungi
that we have so far discovered. As soon as these fungi have destroyed










FUNGUS DISEASES OF

SCALE INSECTS AND WHITEFLY.



BY P. H. ROLFS AND H. S. FAWCETT.



FAVORABLE CONDITIONS IN FLORIDA.
Nowhere else in the world have fungus diseases been employed to
combat scale insects and similar pests to so large an extent as in Flor-
ida. This is largely due to the fact that our climatic conditions are
especially favorable to the spread of fungi. In an arid or semi-arid
region to use these species as natural enemies for combating our pests
would be entirely in vain. It happens however that Florida, in addi-
tion to having an abundant rainfall, has also a moist atmosphere.
The use of fungi and bacteria to produce diseases of insects has
been advocated from time to time as a means of repressing these pests.
The conditions, however, under which many species of insects live are
such as to make it a difficult matter to apply the remedy. Wherever
insects occur that are gregarious in their habits, the disease method of
combating them can be used with advantage. This has been repeatedly
proved by the success that has been attained in destroying the chinch-
bug of the wheat fields and corn fields of the Northwest. While the
climate there is ordinarily too dry to permit fungi to flourish, the
wheat plants and corn plants in their growth give off enough moisture
to make the atmosphere in the fields a rather moist one. It thus hap-
pens that rather unnaturally we have a moist condition in a field
situated in what is usually a dry region.
Many species of scale insects and similar insects in Florida suffer
great annual diminution from fungus diseases. This can be readily
proved by simply treating a scale-infested plant with a fungicide, such
as Bordeaux mixture, which will then destroy the fungi that kill scale
insects, and a great increase of the latter will ensue. That there are
still many undiscovered species of fungus which attack these forms of
insects is clearly shown by the fact that within the last year three
species of fungi have been found to attack the whitefly, which hereto-
fore had not been known to be enemies of this pest.

SCALE FUNGI DO NOT ATTACK TREES.
It is frequently asked whether it is not dangerous to introduce these
fungi into an orchard, the questioner fearing that when introduced
they might produce a disease of the trees, or attack the fruit. No such
dangers need be anticipated from any of the scale-destroying fungi
that we have so far discovered. As soon as these fungi have destroyed






Florida Agricultural Experiment Station.


the scale insects and other pests upon which they live there is no more
food for them to exist upon, and consequently they must perish. One
of our best orchardists, having extensive orchards in the State, has
frequently said that he would prefer to have always two or three scale-
infested trees in the orchard. As long as he had these scale-infested
trees he was sure of knowing just where he could put his hand on
fungus material to keep down the scale insects in the other trees. Of
course in a short time the trees that were originally scaly would become
entirely free from scales, and he would have to look for fungus in
other places. The same speaker stated, that one among the many re-
grets he had after the great freeze was that he had lost not only a
considerable amount of well-grown wood from his trees, but had also
lost all of his friendly fungi; and that he would be somewhat perplexed
to know just where to get these fungi again to protect his trees against
the scale insects.
It is nearly certain-one might say almost beyond question-that
for the most part the diseases of scale insects and whitefly are native
to Florida. While this cannot be stated with absolute certainty, still
the fact that the different fungus diseases appear spontaneously in
widely-separated orchards of the State rather confirms one in this
opinion. In addition to this, quite a number of the fungi which attack
scale insects have been found on trees growing near hammocks in
localities where it would not be probable that they could have been
carried from cultivated orchards.

CARE NECESSARY FOR SUCCESS.
To control scale insects and whitefly by means of the fungus dis-
eases one must pay close attention to minor details, and must make
intelligent observations. It is as impossible to carry out this work
successfully without due regard to the needs of the fungus and the
peculiarity of the insect pest that is to be controlled, as it would be to
use insecticides with the same disregard to details. The writers have
frequently met orchardists who have pinned in a few leaves bearing
whitefly diseased with fungus, and who in six weeks had actually for-
gotten where these leaves had been pinned. In some cases the orch-
ardists expect the fungus to be disseminated to all parts of the grove
after simply tying a few sprigs of such fungus material in one tree.
For such work to be effective it would be necessary to make close ob-
servations of the entire orchard; to find where the greatest amount of
scale or whitefly was located; and to introduce the fungi in such posi-
tions as would give the best opportunity for the spores to spread from
one limb to another, and from one tree to another.
It sometimes happens that orchards become very badly infested
with scale insects before one is aware of the fact; or, stating it in other
words, the orchardist becomes careless and neglects to make observa-
tions in his field as frequently as he should. When such a condition
has arisen, especially in connection with recently-planted or scattered
trees, it will be best to relieve the condition temporarily by spraying
with some contact insecticide; such as whale-oil soap or kerosene emul-
sion (see Florida Agricultural Experiment Station Bulletin 76). This
will give the trees relief by reducing the amount of scale present; and






Bulletin No. 94.


then as soon as the insecticide has disappeared, the fungi may be in-
troduced. Spraying for scale insects in Florida must be looked upon as
merely an expedient for helping any one out of a position into which
carelessness has allowed him to fall.

TIME NECESSARY TO SECURE INFECTION.
In treating any kind of an orchard with fungus to destroy scale
insects or whitefly, one should not lose sight of the fact that it requires
a certain time before the fungus can be sufficiently disseminated
throughout the tree, or throughout the orchard, to do effective work.
During the most favorable weather it will require about four weeks
for the infection to make itself visible to the unaided eye. In the case
of the red-headed fungus of scale insects the minimum time is a little
less than this. During dry weather in summer, or during cold weather
in winter, it will take much longer for the fungus to make a visible
infection. It should be said, however, that many infections occur
which are not visible to the unaided eye. It not infrequently happens,
especially in the case of the San Jose scale, that the red-headed fungus
kills off a very large percentage of the scales without producing any
of the red pustules.

A PRIVATE ENTERPRISE.
Mr. F. P. Henderson, formerly of Arno but now of Gainesville,
Fla., has supplied the fungus material with which hundreds of acres
have been treated during the last two years. He has done this work
as a private enterprise, independently of the Experiment Station, and
is in no wise connected with this institution. The material that he sup-
plies has been, for the most part, so far as our observations go, a mix-
ture of the red-headed fungus and the black fungus. From a practical
point of view, it should be regarded as rather better to have both fungi
than to have either one of them separately, since they thrive best under
slightly different climatic conditions; and therefore if conditions are
such as to cause one fungus to make a weak growth, the other might
probably find conditions suitable for making a stronger growth.

THE EXPERIMENT STATION CANNOT SUPPLY FUNGI.
The Experiment Station is maintained by funds received from the
Federal treasury. The laws and regulations under which the money
is expended are made by Congress for the United States Department
of Agriculture. As the collecting and distributing of fungus is not an
experiment, it could not justly be charged to this fund. Our State
legislature could easily make provision for such work if it was con-
sidered desirable. Fungus material, however, can readily be obtained
from private sources.

WHERE FUNGI MAY BE BOUGHT.
Black and Red-headed Fungi for Scale Insects: F. P. Henderson,
Gainesville, Fla.






Bulletin No. 94.


then as soon as the insecticide has disappeared, the fungi may be in-
troduced. Spraying for scale insects in Florida must be looked upon as
merely an expedient for helping any one out of a position into which
carelessness has allowed him to fall.

TIME NECESSARY TO SECURE INFECTION.
In treating any kind of an orchard with fungus to destroy scale
insects or whitefly, one should not lose sight of the fact that it requires
a certain time before the fungus can be sufficiently disseminated
throughout the tree, or throughout the orchard, to do effective work.
During the most favorable weather it will require about four weeks
for the infection to make itself visible to the unaided eye. In the case
of the red-headed fungus of scale insects the minimum time is a little
less than this. During dry weather in summer, or during cold weather
in winter, it will take much longer for the fungus to make a visible
infection. It should be said, however, that many infections occur
which are not visible to the unaided eye. It not infrequently happens,
especially in the case of the San Jose scale, that the red-headed fungus
kills off a very large percentage of the scales without producing any
of the red pustules.

A PRIVATE ENTERPRISE.
Mr. F. P. Henderson, formerly of Arno but now of Gainesville,
Fla., has supplied the fungus material with which hundreds of acres
have been treated during the last two years. He has done this work
as a private enterprise, independently of the Experiment Station, and
is in no wise connected with this institution. The material that he sup-
plies has been, for the most part, so far as our observations go, a mix-
ture of the red-headed fungus and the black fungus. From a practical
point of view, it should be regarded as rather better to have both fungi
than to have either one of them separately, since they thrive best under
slightly different climatic conditions; and therefore if conditions are
such as to cause one fungus to make a weak growth, the other might
probably find conditions suitable for making a stronger growth.

THE EXPERIMENT STATION CANNOT SUPPLY FUNGI.
The Experiment Station is maintained by funds received from the
Federal treasury. The laws and regulations under which the money
is expended are made by Congress for the United States Department
of Agriculture. As the collecting and distributing of fungus is not an
experiment, it could not justly be charged to this fund. Our State
legislature could easily make provision for such work if it was con-
sidered desirable. Fungus material, however, can readily be obtained
from private sources.

WHERE FUNGI MAY BE BOUGHT.
Black and Red-headed Fungi for Scale Insects: F. P. Henderson,
Gainesville, Fla.






Bulletin No. 94.


then as soon as the insecticide has disappeared, the fungi may be in-
troduced. Spraying for scale insects in Florida must be looked upon as
merely an expedient for helping any one out of a position into which
carelessness has allowed him to fall.

TIME NECESSARY TO SECURE INFECTION.
In treating any kind of an orchard with fungus to destroy scale
insects or whitefly, one should not lose sight of the fact that it requires
a certain time before the fungus can be sufficiently disseminated
throughout the tree, or throughout the orchard, to do effective work.
During the most favorable weather it will require about four weeks
for the infection to make itself visible to the unaided eye. In the case
of the red-headed fungus of scale insects the minimum time is a little
less than this. During dry weather in summer, or during cold weather
in winter, it will take much longer for the fungus to make a visible
infection. It should be said, however, that many infections occur
which are not visible to the unaided eye. It not infrequently happens,
especially in the case of the San Jose scale, that the red-headed fungus
kills off a very large percentage of the scales without producing any
of the red pustules.

A PRIVATE ENTERPRISE.
Mr. F. P. Henderson, formerly of Arno but now of Gainesville,
Fla., has supplied the fungus material with which hundreds of acres
have been treated during the last two years. He has done this work
as a private enterprise, independently of the Experiment Station, and
is in no wise connected with this institution. The material that he sup-
plies has been, for the most part, so far as our observations go, a mix-
ture of the red-headed fungus and the black fungus. From a practical
point of view, it should be regarded as rather better to have both fungi
than to have either one of them separately, since they thrive best under
slightly different climatic conditions; and therefore if conditions are
such as to cause one fungus to make a weak growth, the other might
probably find conditions suitable for making a stronger growth.

THE EXPERIMENT STATION CANNOT SUPPLY FUNGI.
The Experiment Station is maintained by funds received from the
Federal treasury. The laws and regulations under which the money
is expended are made by Congress for the United States Department
of Agriculture. As the collecting and distributing of fungus is not an
experiment, it could not justly be charged to this fund. Our State
legislature could easily make provision for such work if it was con-
sidered desirable. Fungus material, however, can readily be obtained
from private sources.

WHERE FUNGI MAY BE BOUGHT.
Black and Red-headed Fungi for Scale Insects: F. P. Henderson,
Gainesville, Fla.





Florida Agricultural Experiment Station.


Red and Brown Fungi for Whitefly: A. J. Pettigrew, Manatee, Fla.;
A. F. Wyman, Bradentown, Fla.; F. D. Waite, Palmetto, Fla.
Red, Brown, and Yellow Fungi for Whitefly: C. A. Boone, Orlando,
Fla.
Yellow and Red Fungi for Whitefly: C. B. Thornton, Orlando, Fla.
The cost will vary according to the amount needed and the season
at which it is wanted, but two or three dollars will usually buy enough
to treat an acre.

THE RED-HEADED FUNGUS.
(Sphaerostilbe coccophila, Tul.)
Figure 2 is from a photograph of the red-headed fungus growing
on the purple scale on a stem of an orange tree. The red color of the
fungus shows whitish in the illustration.
The senior author of this bulletin was the first to call attention to
the fact that the red-headed fungus is parasitic on the San Jose scale.
The discovery was made at De Funiak Springs, Fla., in May, 1896, and
was subsequently published in "Garden and Forest," 8s. Studies on
this fungus were reported in Florida Agricultural Experiment Station
Bulletin No. 41 (1897) 19.
Immediately after making this discovery steps were taken to find
Means of using it in a practical way to control this pernicious scale.
The results of these experiments showed that it was not only easy to
infect scales that were previously free from the disease, but that the
work could be done profitably under field conditions.
An important fact that was brought out in
the laboratory investigations, and one that is
usually overlooked by those who use the hand-
lens only, is that myriads of scales are infected
and killed by this fungus without its being ex-
ternally visible. It therefore frequently hap-
pens that a scaly tree may be thoroughly over-
run with this fungus, although no pustules are
visible. This point should be especially remem-
bered when one is introducing the red-headed
Fungus.
Dr. S. A. Forbes, State Entomologist, gave
this fungus a thorough trial in Illinois in 1898,
9 and found that the climatic conditions there
were not such as to make it a practical remedy.
Dr. J. B. Smith, 21 of the New Jersey Experi-
ment Station, also gave this fungus a thorough
trial. In both Illinois and New Jersey it is able
____ __ to live over winter and to do some good in the
Fig. 2. Red-headed Fungus. way of reducing the San Jose scale; but in
Enlarged twice, neither case did it flourish as it does in Florida,
where our climatic conditions are peculiarly favorable to its growth.
Even as near to Florida as in Middle Alabama, Professor Earle 8
found that the fungus was not active enough to be considered sufficient
to hold the San Jose scale in check. There can be no longer any ques-





Bulletin No. 94.


tion as to its efficiency in Florida, since hundreds of acres have been
treated by practical orchardists, and since such able men as Prof. H. A.
Gossard 10, Prof. H. Harold Hume 12, Dr. E. H. Sellards, and Dr.
E. W. Berger 1, have observed it from a technical point of view.


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Fig. 3. The Red-headed Fungus.


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Florida Agricultural Experiment Station.


No. 3 of Figure 3 represents a cross section of a scale insect and a
pustule of the red-headed fungus as seen under a microscope. Nos. 4
to 27 show different forms of spores and hyphae as they occur in
nature and on culture media. (See Bulletin 41.)
Mr. C. W. Griffing had the Komoko peach orchard of 650 acres
treated with this fungus during 1906; and at the meeting of the Flor-
ida State Horticultural Society at St. Petersburg in May, 1907, he re-
ported that this treatment was more effective than spraying had been,
with a saving of about 90 per cent. of the cost of the latter operation.
SPECIES OF INSECTS INFECTED.
This species of fungus is effective on a large
number of scale insects. Its virulence varies with
regard to different species in Florida. In Japan 14
it is more effective on Diaspis pentagon than on the
San Jose scale. Next to the San Jose scale, the
purple scale (Mytilaspis citricola) is most frequently
affected. Professor Earle 7 found this scale at-
tacked by it in Porto Rico. The long scale (Mytil-
aspis gloverii) is also frequently destroyed by it.
The round scale (Aspidiotus ficus) 'is frequently
nFig. 4. ethecm killed by it. The scale (Aspidiotus nerii) of the
China-berry tree is usually destroyed by it. Among
wild trees it may be found in great abundance on the obscure scale
(Aspidiotus obscurus) on water-oaks, and on Aspidiotus tenebricosus,
a similar scale on red maple. It has also been found on the chaff
scale (Parlatoria pergandii), which inhabits the limbs and trunks of
citrus trees. It also occurs, but very rarely, on the citrus
whitefly.
Cook and Horne 3 found it present on the purple scale
and on Chionaspis citri, though it was less effective on the
latter. Parkin 15 found it present in Ceylon on the purple
scale, and also on Aspidiotus aurantii, Aspidiotus camelliae,
Aonidia bullata, and A. crenulata. He reports it also as occur-
ring on Fiorinia fioriniae in Mauritius, on Aspidiotus articu- e
latus in West Africa, and Ischnaspis filiformis and Aspidiotus
articulatus in the West Indies. These references are sufficient
to show the world-wide distribution of the fungus, and also ig'u
its habit of attacking many species of exceedingly trouble- Enlarged
some scale insects. 200times.
Figure 4 represents a cross section of a perithecium of this fungus
as seen under a microscope. These forms occur rather rarely in the
groves, but are easily recognized when they do occur by their shape
and deeper red color. The perithecia are much smaller than the
pycnidia.
Figure 5 shows a single ascus of the red-headed fungus greatly en-
larged. The perfect spores are borne inside the ascus.
HOW TO APPLY THE FUNGUS.
Figure 1 shows how the fungus material should be applied to the
tree. The portion of the tree to which it should be tied is that which
is most thoroughly infested with the scale insect which one wishes to
destroy. During the dry weather the fungus spores will remain






Bulletin No. 94.


quiescent in the material that is tied to the tree. When, however,
heavy dews or rains occur, the water washes the spores down the trunks
and over the healthy scales.. The spores then germinate and infect the
scale insects. From this it will be seen that it is preferable to tie the
fungus well up in the tree. It is better, however, not to tie the fungus
so high in the tree as to expose it to the dry winds and hot sun. The
fungus does not spread as well in orchards that are just started or
where the trees are small, as in larger orchards where there is an
abundance of leaves to produce shade, and to transpire more or less
moisture into the atmosphere. Where plenty of infecting material can
be obtained it is advisable to place it in every tree that is infested with
scale insects. It will not be amiss also to place several pieces in large
trees. Though the fungus spores are readily carried from one tree to
another, we know that millions of spores must perish for every one
that finds lodgment in the correct place. It is therefore greatly to our
advantage to have the fungus located in places that are as favorable
to it as possible. In those years when a long-continued drought fol-
lows the application of the fungus material, much of it will be dried
out and killed before the scales are infected. As a matter of fact, we
at times meet with years during which the scale insects have the entire
advantage, but sooner or later we will have a brief season during which
the fungus will flourish and reduce the scale as if by magic.
THE WHITE-HEADED FUNGUS.
(Ophionectria coccicola E. and E.)
This fungus appears to have been first mentioned by Mr. H. G.
Hubbard, 11 in his book "Insects Affecting the Orange," published by
the U. S. Department of Agriculture; though its true value was not
suspected at the time. In fact,
the fungus at that time was
thought to be an injurious para-
site rather than a friendly one.
SIt is more thoroughly distributed
throughout the citrus-growing
sections of Florida than any
other species of fungus. Curi-
ously enough, it happens that
the fungus is not recorded as
occurring on any of our native
scales. For keeping the long
scale and the purple scale in
check it is probably much more
effective in the citrus orchard
than is the red-headed fungus. r
It is certainly much better known
*^ than the latter, and much more
commonly used. The writers
have found the white-headed
Fig. 6. White-headed fungus present in all sections of Fig. 7. White-headed
Fungus. Imperfect the State where citrus groves oc- Fungus. Perfect stage.
stage. Natural size. cur. Sometimes small groves are Enlarged twice.





12 Florida Agricultural Experiment Station.

found without this fungus. Under such circumstances, the long scale
and purple scale make unusual headway, and not infrequently kill
large branches in the trees. Recently-set trees are sometimes killed
by these scales before the fungus has had an opportunity to destroy
the scale. Like the red-headed fungus, this seems to be a tropical
species, occurring in Java, South Africa, the West Indies, and South
America.
Figure 6 is from a photograph of the white-headed fungus growing
on the purple scale on an orange tree.
Figure 7 is from a photograph of the perfect stage of the white-
headed fungus (enlarged twice) killing purple scale on an orange twig.
SPECIES OF INSECTS INFECTED.
Zimmerman 24 found the white-headed
fungus in Java on Parlatoria zizyphi. Cook
and Home 4 found it destroying the purple
scale in Cuba. It was previously reported
by Earle 8 from Cuba on this same scale.
In Florida it has been repeatedly noticed
fig. 8. A Fig. 9. Conidial spore. by all the entomologists of the Experiment
head en- Enlarged 130 Station during the last fifteen years. From
tlames5 times. the literature at hand it would seem that
this fungus is much more effective in keeping down the long scale
and the purple scale in Florida than in any other portion of the world.
Its usefulness with us seems, however, to
be limited to these two scale insects. Fortu-
nately, it is very effective on these two
species, which are the commonest and most
destructive of our scale insects when left
uncontrolled.
Figure 8 shows one of the conidia-bear-
~ ing heads of the white-headed fungu's, en-
Fig. 10. Conidial spore germi- large 15 times.
eating. Enlarged 130 times. Figure 9 shows the peculiar trident
1conidial spore. The arms of the trident close up on drying and open
on comingg damp, causing the spores to move about.
Figure 10 shows a trident conidial spore germinating in water.
HOW TO APPLY THE FUNGUS.
^f' The method of applying this fungus
is exactly the same as that for ap-
plying the red-headed fungus. The
pustules which contain the conidia are
usually a little longer time in making
their appearance than in the case of
the red-headed fungus.
Figure 11 shows a perithecium of ig. 12. As
the white-headed fungus in cross-sec- large 110
Stion. Enlarged 80 times. times.
Fig. 11. Perithecium. En- Figure 12 shows an ascus with ascospores
large 80 times, enlarged 110 times.






Bulletin No. 94.


Figure 13 shows three ascospores enlarged 400 times.
Figure 14 shows the germination of an ascospore in water.









Fig. 14. Ascospore germinating.
Enlarged 180 times.

Fig. 13. Ascospores.
Enlarged 400 times.



THE BLACK FUNGUS.

(Myriangium duriaei Mont.)

The honor of discovering and
first experimenting with this
fungus as a parasite of scale in-
sects belongs to Prof. W. M.
Scott 20 who reported in 1898
successful experiments with it in
destroying the San Jose scale. It
had been collected many times
previously, but had always been
considered as living on the bark
of various plants. Its range of
distribution seems to be more
northerly than that of the white-
headed fungus, and it is prob-
ably not so widely distributed as
the red-headed fungus. For the
most part, the observations as to
Fig. 15. Imperfect the scales upon which it lives have
stage. Natural been less carefully made than in Fig. 16. Perfect stage.
size. other cases. The writers have Natural sze.
seen specimens from all parts of the State, and it is probable that it
is more generally distributed throughout Florida than either of the
foregoing species.
Figure 15 is from a photograph of the immature stage of the black
fungus killing the chaff scale on an orange twig.
Figure 16 is from a photograph of the perfect stage of the black
fungus killing scales on an orange twig.





Florida Agricultural Experiment Station.


SCALE INSECTS ATTACKED.
Cook and Home 5 found it parasitic on
the purple scale and less commonly on
Chionaspis citri in Cuba.
Zimmerman 23 found it para-
sitic in Java onIschnaspis fil-
iformis, a coffee scale. Pro-
fessor Earle 7 found it de-
stroying the purple scale in
Porto Rico. He also found
Fig. 17. Cross section of perfect it in Cuba s on the purple Fig.18. Ascus. En-
stage. Enlarged 70times. scale. A fungus referred to large 350 times.
by Professor Hume 13 in his book, Citrus Fruits and Their Culture,
is probably this species. It also occurs on the long scale and on the
San Jose scale in Florida. Parkin 17 reports it as occurring on Isch-
naspis filiformis in Java, and on Aspidiotus camelliae
r. and Chionaspis biclavis in Ceylon. The peculiar habit
tiL of this fungus in forming a heavy black crust, makes
( it more difficult to determine the species of scale para-
sitized. For this reason many of the records of its
parasitism are rather indefinite.
Fig. 19. Spores. En- Figure 17 shows a cross section of the mature
lrged o00 times. fungus bearing the asci.
Figure 18 shows an ascus of the black fungus with spores.
Figure 19 shows spores of the black fungus.
HOW TO APPLY THE FUNGUS.
The fungus occurs on any portion of the tree infested by the scale
host. When it occurs on the fruit it is rather difficult to wash off, and
hence it is not surprising that some citrus growers who did not suspect
its usefulness sought advice as to how it could be destroyed. To apply
the fungus, a small sprig three to six inches long should be tied to the
scale-infested portion of the tree. It is best to put the fungus as nearly
as possible in contact with the scales we desire to infect. In some
instances we have found that the fungus was slow in killing the scales,
especially in small trees, but that finally the eradication was perfect.
In one case the fungus was a year and a half in killing off the last
remnant of scale, but the same tree has remained free from scales down
to the present day-a period of over four years.

THE YELLOW FUNGUS OF THE WHITEFLY.
(Aschersonia flavo-citrina.)
This fungus was first described from specimens collected in Brazil
on guava leaves. It was discovered in Florida two years ago. It
resembles the red whitefly fungus in habits and general appearance,
except in the matter of coloring.
HOW TO APPLY THE FUNGUS.
It has not been possible yet to work out completely the best methods





Bulletin No. 94.


of applying this fungus on account of its having been but recently
discovered. The fact that it is very closely related to the red fungus
of the whitefly, from which it differs only in minor details, leads us
to believe that the methods used for the red fungus will be applicable
to the yellow fungus. (See below.)
THE RED FUNGUS OF THE WHITEFLY.
(Aschersonia aleyrodis Webber.)
















Fig. 20. Red Fungus of Whitefly. Natural size.
This fungus was discovered and described by Dr. H. J. Webber 22
In Bulletin 88 of the Florida Agricultural Experiment Station 2 will
be found a full discussion of this fungus and methods for its employ-
ment. The following brief directions may be useful.
HOW TO APPLY THE FUNGUS.
The Leaf-pinning Method.-A simple, and also very effective
method for introducing this fungus, is to secure some leaves on which
it occurs and pin these in whitefly-infested trees. If this work is done
about the beginning of the rainy season, one is pretty certain to get
.a start of the fungus; especially if the whitefly is somewhat abundant.
There is, however, much opportunity for exercising judgment as to
the part of a tree in which the fungus-bearing leaves should be placed;
.as well as in the choice of trees in which to begin starting this fungus.
Generally speaking, it is best to pin the fungus in the interior of the
tree. We prefer to place the leaves with the fungus-bearing side down-
wards. If at the same time a small piece of paper is pinned to the
upper surface of the leaf to which the fungus-bearing leaf is pinned
it will greatly aid one in finding the leaves later, when one wishes to
examine the condition of the fungus. A water-sprout in the interior
of the tree is pretty certain to be heavily infested with larvae and
mature whiteflies, and is an excellent place to pin fungus-bearing leaves.
A month or six weeks must elapse before much new fungus can be
,expected.
Figure 20 is from a photograph of the red fungus killing whitefly
larvae on an orange leaf.






Florida Agricultural Experiment Station.


Spore-spraying Method.-Dr. Berger, Entomologist of the Experi-
ment Station, has demonstrated that spore-spraying is a very effective
and economical way of applying the fungus. (See Florida Agricultural
Experiment Station Bulletin 88, p. 60.) Briefly stated, the method is.
as follows:-Place a dozen or more leaves bearing an abundance of
fungus pustules in a pail of water. Stir well and allow it to stand for
15 to 30 minutes. Stir again, and strain the liquid through cheese-
cloth into a spraying machine. Apply as far as possible to the lower
surface of the leaves. Do not allow the liquid to settle after pouring
it into the spraying machine. Apply only a small amount of liquid,
since any that runs off to the ground is wasted. Use only spraying
machines that have not been previously in use for applying fungicides
on insecticides. Use only such machines as have no brass or copper.
excepting on the nozzle. The best forms of machines are the small.
auto-sprays which are operated by compressed air.

THE BROWN FUNGUS OF THE WHITEFLY.



'_















Fig. 21. Brown Fungus of Whitefly. Natural size.
(Photo by H. H. Hum..)
This fungus has not received a scientific name, as its spore-bearing
stage is not known. It was discovered and first experimented with
by Dr. H. J. Webber. For a fuller discussion of this fungus and the
methods of using it see p. 64 of Bulletin 88 of the Florida Experiment
Station.
Figure 21 is from a photograph of the brown fungus killing white-
fly larvae on an orange leaf.
HOW TO APPLY THE FUNGUS.
The spores of this fungus are not known at present; hence, the
leaf-pinning method and the spore-spraying method just described for
the red fungus cannot be recommended.





Bulletin No. 94.


Tree-planting Method.-Several people in the State prepare nursery
trees for sale bearing a quantity of this fungus on their leaves. Trees
bearing .. hit. H. diseased with this fungus are planted in pots or tubs.
They are then placed so that their leaves and branches can mingle
with the leaves and branches of the trees in the grove. This method
requires constant care in the way of watering until the fungus has
spread naturally to the tree in which it is wanted.

REFERENCES.
1. Berger, E. W.-Fla. Exp. Sta. Rept., p. 37, 1907.
2. Berger, E. W.-Fla. Exp. Sta. Bul. 88, 1907.
3. Cook, M. T., and Home, W. T.-Insects and Orange Diseases.
Cuba Exp. Sta. Bul. 9, pp. 22, 25, 1908.
4. Cook, M. T., and Home, W. T.-Cuba Exp. Sta. Bul. 9, p. 22.
5. Cook, M. T., and Home, W. T.-Cuba Exp. Sta. Bul. 9, pp. 23, 25.
(i. Earle, F. S.-Ala. Exp. Sta. Bul. 106, p. 175, 1899.
7. Earle, F. S.-Ann. Rep. Office of Exp. Sta., p. 457, Washing-
ton, D. C., 1903.
8. Earle, F. S.-First Cuban Exp. Sta. Rept., p. 162, 1904-5.
9. Forbes, S. A.-Ill. Exp. Sta. Bul. 56, p. 270, 1899.
10. Gossard, H. A.-Fla. Exp. Sta. Bul. 61, p. 479, 1902.
11. Hubbard, H. G.-Insects Affecting the Orange, U. S. Dept. of
Agr., Div. of Entomology, Washington, D. C., p. 2, 1885.
12. Hume, H. Harold-Citrus Fruits and Their Culture, p. 548.
13. Hume, H. Harold.-Citrus Fruits and Their Culture, p. 550.
14. Kuwana, S.-The San Jose Scale in Japan, p. 26, 1904.
15. Parkin, J.-Ann. Roy. Bot. Gard. Peradeniya, Vol. III, pt. 1,
pp. 49-50, 1906.
16. p. 27.
17. p. 32.
18. Rolfs, P. H.-Garden and Forest, Vol. X, pp. 217-218, 1897.
19. Rolfs, P. H.-Fla. Exp. Sta. Bul. 41, 1897.
20. Scott, W. M.-Ga. State Hort. Soc. Rept. 22, pp. 69-70, 1898.
21. Smith, J. B.-18th N. J. Exp. Sta. Rept., pp. 470-479.
19th N. J. Exp. Sta. Rept., pp. 445-446.
24th N. J. Exp. Sta. Rept., pp. 565-567.
22. Webber, H. J.-U. S. Dept. of Agr., Div. of Veg. Physiol. and
Path., Bul. 13, p. 20, Washington, D. C., 1897.
23. Zimmerman, A.-Central. fiir Bakt. II, Vol. 7, p. 876.
24. Zimmerman, A.-Ann. of Roy. Bot. Garden Peradeniya, Vol. III,
pt. 1, p. 27, 1901.




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