Official Organ of the Florida Entomological Society
VOL. III WINTER NUMBER NO. 3
(Printed in January, 1920)
*MOSQUITOES FOUND ABOUT GAINESVILLE, FLA.
By U. C. LOFTIN
MOSQUITOES AND DISEASE
Malaria has been known for a long time, but it is only recently
that it has been shown to be caused by a sporozoan parasite, be-
longing to the family Plasmodidae, and that it is transmitted by,
and only by, Anopheline mosquitoes.
The idea that mosquitoes might spread malaria had been sug-
gested many times, but it was not until 1898 that Dr. Ronald
Ross, of the London School of Tropical Medicine, worked out the
life history of the parasite causing "bird malaria" and found the
spores developing in the stomach of the mosquitoes. A little later,
Grassi, following Ross' theory, demonstrated the transfer of
human malaria by Anopheline mosquitoes. Since that time, it
has been confirmed by such a large number of workers that there
can no longer be any doubt.
*This is the second installment of Mr. Loftin's paper and concludes Part I. The first
installment was printed in the previous number. Part II, "Traps for Mosquitoes," will
appear in the next number. All the figures for Part I were printed in the previous number.
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THE FLORIDA BUGGIST
Theobald (1901) in his Monograph reports forty-two species of
Anopheles from the world. There are eleven species found in
the canal zone, at least five of which carry malaria (Darling,
1910). But we, in the United States, have only three that ordi-
narily carry malaria. These are Anopheles punctipennis Say.,
Anopheles quadrimaculatus Say., and Anopheles crucians Wied.
(Howard, 1911), the last two being found in Florida.
While the etiology of malaria is well understood, few people
realize the importance of it. They take it as a matter of provi-
dence that every one in the South should have it and that it does
not amount to much. -Indeed, it is very difficult to estimate the
damage it does. But Herrick (1903) says that malaria is re-
sponsible for more sickness among the white population of the
South than any other disease. Howard (1907) points out that
from the meager data available, the death rate from malaria in
the United States amounts to fifteen per hundred thousand, or
twelve hundred per year, and that two-thirds of this is in the
South. Although there are no records available for this state,
Florida, with its semitropical climate, summer rains and large
areas of flat lands, undoubtedly has its share. But the death rate
alone does not begin to show the importance of the disease.
Howard (1909) says:
"But with malaria perhaps as with no other disease, does the death rate
fail to indicate the real loss from the economic point of view. A man may
suffer from malaria throughout the greater part of his life, and his pro-
ductive capacity may be reduced from fifty to seventy-five percent, and yet
ultimately he may die from some entirely different immediate cause. In
fact, the predisposition to death from other causes brought about by malaria
is so marked that if, in the collection of vital statistics, it were possible to
ascribe the real influence upon mortality that malaria possesses, this disease
would have a very high rank in mortality tables. Writing of tropical condi-
tions, Sir Patrick Manson decided that malaria causes more deaths, and more
predisposition to death by producing cachetic states predisposing to other
affections, than all the other parasites affecting mankind together. How-
ever, it has been shown that the average life of the worker in malaria places
Sis shorter and that infant mortality is higher than in healthy places."
Malaria is undoubtedly the most prevalent disease among the
students. The records of the University Infirmary show that
for the present scholastic year (up to May 5, 1913) there were
a total of seventy-two cases treated in the infirmary, thirty-one
of which were for malaria. This is in spite of the fact that there
is, among the students, a strong aversion to going to the infirm-
ary and that only the more serious cases were recorded. The
records show that the time spent in the infirmary for treatment
varies from one to ten days, with an average of three and one-
tenth, or a total for the year of ninety-six. But, as pointed out
above, these records do not begin to show the loss of efficiency
among the students, which is much higher than is shown by these
We have only to turn the pages of history to see how fatal an
epidemic of yellow fever may be. In 1773, Philadelphia was
nearly wiped from the map. In 1853 there was a severe epidemic
throughout the South, New Orleans alone having a mortality of
eight thousand. In 1878 another severe epidemic swept this
region, and spread up the Mississippi Valley, causing twelve
thousand deaths. In 1892 there were one hundred and ninety-
two deaths at Pensacola, and more recently there was an out-
break, in 1905, in which nearly one thousand lives were lost. It
was clearly demonstrated by Reed, Carroll, Lazear and Agro-
monte, a Board appointed by the Surgeon-General of the United
States Army to investigate this disease, that yellow fever is car-
ried by a mosquito, Stegomyia calopus. The work done in the
recent epidemic, in 1905, shows that an epidemic can be stamped
out by destroying these mosquitoes.
We have Stegomyia present in large enough numbers to cause
trouble should an epidemic break out. I have killed as many as
a half dozen in the laboratory in one afternoon, and for a while
during the fall of 1911 they were very troublesome during the
day at the Experiment Station. At present, there is no danger
from them because we have no causal agent present to start an
epidemic, but it may be introduced into Florida ports at any
time, and this will be especially true with the increased trade
incident to the opening of the Panama Canal.
Dengue fever is another mosquito-borne disease that is of in-
creasing importance. Dr. J. H. Hodges, local agent of the State
Board of Health, estimates that there were five thousand cases
in this county alone last year. While this estimate is probably too
high, it shows that this disease must be reckoned with in the
NATURAL ENEMIES OF MOSQUITOES
Some adult mosquitoes are destroyed by birds, bats, dragon-
flies, and other predacious insects, but their number is compara-
A small mite determined by Dr. Nathan Banks as a Hydrach-
nid, close to the genue Thyas, has been found parasitic on the
body of Anopheles. During October and November, it was found
attached to from ten to fifteen per cent of the Anopheles caught,
THE FLORIDA BUGGIST
but never in a single instance to Culex. As many as eight and
ten have been counted attached to the thorax and abdomen of
some individuals; but it is doubtful if any mosquitoes are killed
The larvae are more easily preyed upon and we have some
enemies that are very effective in holding them in check. There
are a few water beetles, especially in the sinks, that feed upon
the larvae. This community is a regular paradise for dragon-
flies and there are from fifty to seventy-five species found. Any-
where around the grounds, on a quiet day, one can see scores of
them. Their larvae feed upon mosquito larvae and being present
in such large numbers devour many of them. Two well grown
dragon-fly larvae have eaten thirty-five Culex larvae over night.
Dragon-fly larvae have been found in the larger areas of water
in all the marshes surrounding the University, but have not been
found in the sink holes.
The most active enemies* we have are the little top minnows
(Gambusia affinis) (Fig. 22, p. 22) and the "goggle-eye" or a
warmouth bass (Chaenobryttus gulosus) (Fig. 23, p. 28). The
usefulness of the top minnows has been mentioned by other writ-
ers (Howard 1902, Van Dine 1906). It is surprising how many
mosquito larvae these little fellows will eat.. A half dozen of them
have eaten over a hundred Culex larvae in a couple of hours, and
ten of them have eaten two hundred larvae (all that were fed
them) for several days in succession. They are very active and
one has only to stand quietly on the bank to see them as they
patrol the water every few minutes. They have been found-in
the deeper portions of all the marshes, the sink holes, ditches, and
wherever there is a permanent supply of water. Their small size
enables them to go almost anywhere and to work their way in
among the vegetation. Wherever they are found is a poor place
to look for mosquitoes.. They have been found in only one in-
stance in the same pond with mosquitoes. This was in a circu-
lar depression covering four or five acres, lying about a mile
northwest of the University. The depression is shallow and the
slope from the bank toward the center is very gradual. It is
overgrown with water weeds and in some places the edges are
surrounded with sphagnum moss. Anopheles larvae were found
abundant in some places among these weeds and moss. In some
cases, the weeds and moss were so thick that the water could not
be seen at all and it looked as though the larvae were actually
*Determined by Dr. H. S. Davis.
resting upon the moss. The minnows were all about the edges,
but in some places the vegetation was too thick for even them.
Wherever a little open water was found, there were the minnows
but no mosquito larvae. They are very hardy and are entirely
capable of freeing and keeping free from mosquitoes, any area
of permanent water. They can be very readily introduced into
ponds and aquaria that are not already stocked with fish of some
kind. They are oviparous and breed all the year, so a few only
would be necessary for a start.
In the sink holes we have also -the "goggle-eye" which is pre-
daceous upon mosquito larvae. Four of these ate two hundred
full grown larvae and ten Gambusia in four hours. Another rec-
ord shows that they ate one hundred and fifty Culex and thirty-
five Gambusia within forty-eight hours, and still another that
they ate three hundred Culex in one hour. The sinks are well
stocked with them. I have several times caught fifteen or twenty
in an hour with a hook and line. In about one hundred specimens
caught, this was the only species found. They do not seem to
prey upon Gambusia naturally, for both are found abundant in
the same sink. It was very fascinating to watch one of these
fish, six inches long, chase a tiny wriggler. They seem very
hardy and can be kept in an aquarium without much trouble.
These and Gambusia keep the sink holes entirely free. I have
several times during the year, carefully examined the sinks with-
out ever finding a single larva.
PREVENTIVE FOR MOSQUITOES
This subject is naturally divided into two parts. Preventives
for (1) Adults and (2) Larvae. There are endless protective
fluids that have been recommended for protection from the bite
of the adult. These usually contain some essential oil such as oil
of citronella, castor oil, pennyroyal oil, kerosene, oil of tar, etc.,
and many are undoubtedly repellant to mosquitoes. But all of
them are more or less disagreeable to use and have to be fre-
quently renewed to be effective, and, all in all, they are a poor
Screens and canopies afford great protection, but as ordinarily
used do not keep out all of the mosquitoes. Examination of rooms
in Thomas Hall has shown as high as thirty mosquitoes present,
ten of which were Anopheles (crucians and quadrimaculatus).
This is in spite of the fact that the dormitories have as good
screens as money can buy, showing how hard it is to keep mos-
quitoes out if they are present.
THE FLORIDA BUGGIST
Smudges of almost any material that give a dense smoke have
been used and, if the smoke is thick enough, will keep adults away
should anyone prefer to be suffocated rather than bitten to death.
Fumigants will quickly rid a house of the pests and are very
useful in some instances. Sulphur dioxide, made by burning two
pounds of sulphur per thousand cubic feet, has been the stand-
ard in the past and is absolutely reliable but it is objectionable
to use on account of its injurious effect upon household goods.
Pyrofume, a product obtained from the fractional distillation of
pine wood, seems to be as effective as sulphur dioxide and less
objectionable to use (Francis, 1906). Mimms' culicide, made
by mixing equal parts by weight of melted carbolic acid crystals
and camphor gum, used at the rate of four ounces per thousand
cubic feet is entirely satisfactory but expensive. In experiments
conducted by the writer, it killed all the Culex quinquefasciatus
which were confined in the room in a battery jar covered with
cloth. It is much easier to use and not so injurious 'as sulphur
dioxide. Tobacco smoke will quickly kill mosquitoes confined in a
tight receptacle. As tobacco is so universally distributed and
cheap, it would be very convenient to use if it would form an
effective fumigant. In experiments conducted by the writer, the
great difficulty was in burning it so as to make a smoke. When
alcohol or saltpeter was mixed in sufficient quantities to burn it,
it would burn without making much smoke and was not effective
when burned in a tight room at the rate of two ounces per thou-
sand cubic feet. It is believed that if some device for burning
tobacco so as to make a dense smoke can be perfected, it will
form a cheap and efficient fumigant. Perhaps something like the
"smoker" used for bees could be used successfully.
Tobacco decoction (containing about two and two-thirds per
cent nicotine) was tried in a tight room containing about seven
hundred cubic feet of space. Twenty-five cubic centimeters were
evaporated over a gas burner and one hundred and four Culex
quinquefasciatus exposed to the fumes for thirty minutes. All
of them were stupefied, but when removed to fresh air, about
seventy-five per cent revived. Another experiment was made in
which ninty-five cubic centimeters were evaporated in the same
room and about fifty Culex quinquefasciatus exposed to the fumes
for one hour. In this experiment none of them were killed. Some
trouble was found in evaporating this much of the decoction, as
it forms a thick syrupy mass and vaporized slowly. It is thought
that "Black Leaf 40" which contains nicotine sulphate can be
used to much better advantage, but none was available for experi-
ment. As it contains about fifteen times as much nicotine per
volume as the other decoction, probably no difficulty will be ex-
perienced in evaporating a sufficient quantity to kill the mosqui-
toes if it proves effective.
Oil of turpentine was tried as a fumigant, but it caught on fire
so the experiment was discontinued. It burned with a dense
smoke which completely filled the room, but did not kill the mos-
quitoes. Green camphor leaves dried in an oven and burned at
the rate of two ounces per seven hundred feet were not effective.
It is important that the evaporating vessels for any fumigants
be placed near the floor, otherwise the mosquitoes near the floor
will not be harmed, as the fumes are lighter than air.
PREVENTIVE FOR LARVAE
Preventive and remedial work against the adults is desirable
and often very effective, but it is only temporary and does not
destroy the root of the trouble. It is better, in all cases where it
is possible, to either kill the larvae or to destroy or render unin-
habitable the breeding places. It is more satisfactory and usually
cheaper in the long run to destroy the breeding places. The pecu-
liar habits and structure of the larvae make it possible to kill
them rather easily with substances called "larvacides." These
substances float on the surface, forming a film which prevents the
larvae from reaching the air with their breathing tubes. Various
substances have been tried and many have given good results,
but considering everything, petroleum products have proved the
most satisfactory. It was suggested as early as 1812 that kero-
sene was effective in killing larvae, but the use of it did not be-
come very general until about 1895. Since then it has been used
extensively with good results. H. W. Weed rid the campus of the
Mississippi Agricultural College of mosquitoes by oiling eleven
water tanks. Professor Kellogg found that by pouring a little
kerosene in some post holes that the mosquito plague was almost
immediately alleviated at Leland Stanford University. Mr. W.
C. Kerr did some extensive work on ponds and swamps on Staten
Island, and Dr. J. B. Smith reports its successful use in two cases
on Long Island. An oil suitable for this work should be light
enough to spread rapidly and yet heavy enough not to evaporate
too readily. A low grade oil known as fuel oil has been found best
suited for this. Mr. H. J. Quayle (1906) used a mixture of a
heavy, eighteen degree Baume, oil and a light, thirty-four degree
(Continued on page 48)
Official Organ of The Florida Entomological Society, Gainesville,
PROF. J. R. WATSON.-........---.... ..........-----------...------Editor
PROF. WILMON NEWELL.........-- --..........--------.Associate Editor
DR. E. W. BERGER ----...--..------------Business Manager
Issued once every three months. Free to all members of the
Subscription price to non-members is $1.00 per year in ad-
vance; 25 cents per copy.
TRICHOGRAMMA MINUTUM TO THE RESCUE
The issue of the Weekly News Letter of the U. S. D. A. for
January 14 bears a reassuring message to the great corn belt. It
has been found that the European Corn Borer seriously damages
only sweet corn and the smaller varieties of flint corn, and that
only in regions where the insect has two generations per year.
In at least the northern part of the chief corn belt only one
generation per year has appeared. Also little damage is done
where weeds are kept down in corn fields, fence rows and waste
places. And lastly, the above named common hymenopterous
parasite is attacking a large percentage of the eggs. However,
no one knows how many generations the insect would produce
during a Florida season, nor its effect upon our flint corn and
PLANT COMMISSIONER WILMON NEWELL, PRESIDENT
OF THE ECONOMIC ENTOMOLOGISTS
Our society was signally honored at the St. Louis meeting of
the American Association of Economic Entomologists by the
election of one of its members as president of that association.
In celebration of this honor some of his Florida friends ten-
dered to Prof. Newell a surprise banquet on the evening of Janu-
ary 12. There were present some fifty guests from the Univer-
sity faculty and Plant Board offices, including the entire Plant
Board (alias Board of Control). Mr. Hodges of Lake City, pres-
ident of the Plant Board, acted as toastmaster. Toasts were
responded to by the members of the Plant Board, the president
and faculty of the University.
ANNOTATED LIST OF THE INJURIOUS AND BENEFICIAL
INSECTS OF THE AVOCADO IN FLORIDA*
By G. F. MOZNETTE
Entomological Inspector, U. S. Department of Agriculture
Trialeurodes floridensis Q.-The Avocado White Fly. Like citrus, the
avocado also possesses its particular white fly. This species attacks the
avocado in the more protected growing sections as does the Dictyospermum
Scale. It is smaller than any of the citrus white flies, possesses white wings
and a pale yellowish body. The pupae are readily distinguished by having
a characteristic fringe. It multiplies rapidly during the summer months,
and causes sooty mold in considerable abundance where present. The
avocadoes growing along the keys and ocean shore are more particularly
attacked by this white fly than are those growing on the mainland. Trees
in the nursery which are more or less protected often become badly infested
with this species. The species is present in Florida wherever avocadoes
Tetranychus yothersi McG.-The Avocado Red Spider Mite. The red
spider mite which attacks the camphor in the northern part of Florida,
seriously attacks the avocado at certain times of the year. This is particu-
larly true during the dry winter months. This mite, when abundant, gives
a grove a very unsightly appearance, by yellowing and browning the foliage.
It is the only red spider mite known to the writer which lives and performs
its depredations on the upper surface of the foliage.
Heliothrips hemorrhoidalis Bouche.-The Greenhouse Thrips. This species,
which is so common in greenhouses in the northern states, attacks the avo-
cado in Florida in the open, and is present in varying numbers throughout
the year. It becomes seriously abundant in places on the approach of dry
weather in the fall and winter, and is capable of doing considerable damage
by causing defoliation. It works on the upper surface of the foliage as does
the avocado red spider mite. It also attacks the fruit when it becomes num-
erous. Like the white fly of the avocado it multiplies more rapidly in the
orchards situated on the keys and beach places in southern Florida.
Chrysomphalus dictyospermi, Morgan.-The Dictyospermum Scale is a
small circular scale of a light brown color. It is particularly abundant on
the avocado in the more protected places, and where the temperatures are
more even. Especially is this true along the ocean shore and keys. It
attacks the branches killing many of the smaller limbs, but when abundant
may often kill the tree.
Saissetia oleae, Bernard.-The Black Scale becomes particularly notice-
able in avocado groves on the keys and ocean front, especially during the
fruit forming period, by congregating in masses about the stems of the
fruits. Here it produces honey dew which accumulates on the fruit in which
the black sooty mold develops necessitating washing of the fruit. Fruits
so attacked by this scale bear weak stems and invariably drop prematurely.
It does not apparently become abundant on the mainland.
Pseudococcus nipae, Mask.-The Cocoanut Mealy Bug becomes noticeable
*Published by permission of the Secretary of Agriculture, U. S. D. A.
THE FLORIDA BUGGIST
at times on the avocado in certain sections where it has become established.
It attacks the foliage particularly.
Pulvinaria pyriformis, Ckll.-The Pyriform Scale. This species, where
present, does considerable damage to the avocado. It is brownish in color,
rounded or ovate in shape, and on maturing, when the egg sacs are pro-
duced, a cottony material pushes out from under the edges of the scale. It
produces an abundance of honey dew for sooty mold to develop. The scale
is prevalent wherever the avocado is grown, especially on seedling trees
growing in neglected yards.
Frankliniella cephalica var. masonii, Watson.-This species of thrips
which is light yellow in color attacks the avocado in the bloom. The writer
has observed that the West Indian varieties growing in groves along the
keys and on the mainland become infested with it. The thrips deposits its
eggs in the pedicel of the flower clusters. These punctures at times are very
numerous, depending on the variety of avocado, causing the flower cluster
to drop. The species differs from the citrus thrips in being considerably
lighter in color.
Empoasca minuenda, Ball.-The Avocado Leaf Hopper. This leaf hopper
which is exceedingly small and yellowish in color attacks the avocado foliage
by sucking the plant juices. It confines its attacks to the lower surface of
the leaf and causes white spots to appear on the foliage viewed from above.
When very numerous, this species will give an avocado tree a decidedly
whitish appearance. It is particularly abundant on the avocado during the
Gracilaria sp. near niolacella Clem.-The Avocado Leaf Roller. This
small greyish moth is present wherever avocadoes are grown. It deposits
its eggs on the new growth. The larvae which hatch from these eggs curl
the foliage on which they feed. The foliage on maturing develops unevenly
giving the tree a decidedly ragged appearance, especially is this true when
this species is abundant. The larvae are small and yellowish in color.
Dysdercus suturellus H. Schf.-The Cotton Stainer. This is one of the
plant bugs and often attacks the fruit of the avocado in considerable num-
bers. The species congregates on the fruit where it injures it by punctur-
ing and sucking the plant juices. The punctures afford entrance places for
plant diseases to enter and develop. It is only in certain years that this
insect appears in the groves.
Acysta perseae Heid.-The Avocado Tingid. This species, which feeds
upon the juices of the foliage of the avocado, is a small lace bug. The in-
sect causes the leaves to appear yellowish and drop. The species is not
widely distributed, however.
Anomala undulata, Mels.-This small beetle, or leaf chafer, visits the
avocado groves in swarms during the blooming period in southern Florida
during certain years. It is nocturnal in its habits, coming out from the
soil at night and devouring the bloom wherever present. Its depredations
last only a week or so, the adults returning to their breeding grounds. It is
not known where they breed. This species is capable of doing considerable
Caulophilus latinasus.-This small brownish weevil, which resembles the
grain and rice weevils, attacks the seed of the avocado in the orchard in
fallen fruits and wherever seed is stored for planting purposes. The larvae
and weevils completely tunnel the seed rendering them worthless.
Sparganothis (Platynata) sp.-A moth, which is of a light brown color,
deposits its eggs in the avocado blossom cluster. The larvae which hatch
from these eggs in turn tie the blossom cluster together with their webs
to form a nest; the larvae feed on the flower parts. This insect has not
been noticed in large numbers nor is it widely distributed. Wherever they
.should become abundant, they would be capable of considerable injury. The
larvae when full grown are about a half inch in length and a dark green
Lypsimena fuscata, Lec. and Elaphidion inerme, Newm.-These two
Cerambycid beetles attack the dying or unhealthy branches of the avocado.
This is true especially after a freeze. If the dying branches are allowed
to remain the borers or larvae often burrow down into the healthy tissue
beyond the axis of the branches.
A number of scale insects of minor importance have at times been noticed
on the avocado doing damage to individual trees. Some of these are the
Common Mealy Bug, Pseudococcus citri Risso; Florida Wax Scale, Cero-
plastes floridensis Comst.; Hemispherical Scale, Saissetia hemisphaerica
Targ.; and the European Fiorinia, Fiorinia floriniae Targ.
A number of beneficial insects, either predatory or parasitic on the prev-
iously named injurious insects of the avocado in Florida, are as follows:
Sympiesis dolichagaster, Ashm.-Represents a parasite which keeps the
avocado leaf roller in check to a considerable extent. It is a small greenish
colored hymenopterous insect.
Chrysopa lateralis, Guer.-This lace wing fly is present on the avocado in
considerable numbers at the time the avocado red spider mite is present in
abundance. The larvae of this species carry with them a protective covering
of small particles which is characteristic of some lace wing flies. The larvae
devour large numbers of the red spider mites.
Franklinothrips vespiformis, Crawford.-This is a large species of thrips.
It is black with a whitish band and is very active on the foliage when dis-
turbed. It is present in large numbers on the avocado in the late winter or
early summer. The larvae and adults of this thrips destroy large numbers
of all stages of the avocado red spider mite. The adults resemble ants on
the foliage. It is also predatory on the larvae of Heliothrips hemorrhodalis
Bouche' and the nymphal stages of Empoasca minuenda Ball. It attacks
the avocado white fly, Trialeurodes floridensis Q., in the larval and pupal
stages as well as the egg stage. This thrips is peculiar in its habits in that
it spins a cocoon, on the lower surface of the leaf, in which the larva pupates.
The larvae are a deep red in color also possessing a whitish band on the body.
Scymnus utilis, Horn.-This insect is commonly found among the red
spider mite colonies on the avocado. It is a small lady bird beetle about the
size of a pin head, black in color. With the beetles may be found their dark
brown larvae, also feeding on all stages of the red spider mite. This species
is very beneficial.
Scymnus kinzeli, Casey.-Another lady bird beetle. It is larger than the
former and is bicolored, abdomen black and head reddish. It is never abund-
Leptothrips mali, Hinds.-This is a large black thrips and is very active
on the foliage. When disturbed it elevates its body as if going to sting.
THE FLORIDA BUGGIST
It is not abundant, and is found predatory in both the larval and adult stage
on the avocado red spider mite.
Prospaltella sp.-This species is a small hymenopterous parasite, fre-
quently bred from the pupal and larval stages of the avocado white fly,
Trialeurodes floridensis Q.
Cryptognatha (Delphastus) pallida, Lec.-This a small lady bird beetle,
light brown in color and about the size of a pin head. It is one of the
Scymnus group. The larvae are whitish in color. Both the larvae and adults
are very beneficial, being predatory upon the avocado white fly in the larval
and pupal stages.
Scolothrips sexmaculatus, Pergande.-This thrips, which is light in color,
possesses six spots on the abdomen. It was not found by the writer to be
abundant and feeds when present in both the larval and adult stages on all
stages of the avocado red spider mite, Tetranychus yothersi, McG.
Aspidiotiphagus citrinus, Craw.-A hymenopterous parasite found to be
destroying considerable numbers of the dictyospermum scale, Chrysomphalus
MOSQUITOES FOUND ABOUT GAINESVILLE, FLA.
(Continued from page 43)
Baume, oil in some pool and creek beds that could not be readily
drained, with good success. He found this to be efficient for
from one to four weeks, depending upon the nature of the pond
and the exposure to the wind. To be on the safe side, the pond
should usually be oiled every two weeks. He used a barrel spray
pump in the accessible places and a knapsack pump in the others
to good advantage, but it may be simply poured on from a sprink-
ler or applied from a bucket with a mop. In inaccessible swamps,
it is sometimes applied by standing a barrel on end and boring a
small hole near the bottom so there will be a constant drip.
In the Panama Canal work there was considerable difficulty
in getting the oil to completely cover the surface when the vegeta-
tion was thick. There they found a solution made from one hun-
dred and fifty pounds of sulphuric acid, one hundred and fifty
pounds of powdered resin, and thirty pounds of caustic potash
boiled together made a good larvaecide (Gorgas 1909), which,
in some cases, was more effective than fuel oil.
A pool on the campus between Buckman and Science Halls, and
the septic tank back of Thomas Hall, have been treated with
"Zenoleum" disinfectant twice. This forms a milky mixture
with the water and kills the larvae in a short time. Both pupae
and larvae were found alive four hours after application, but all
were dead next morning. No record was obtained of how much
was applied, but enough to make the water appear decidedly
milky. It was found to prevent egg laying for about twelve days,
and should be applied about every two weeks.
Ordinary kerosene is commonly used when only small areas
are to be oiled. It is more expensive than crude oil and not any
Any system of oiling has to be done every few weeks during
the year, which in the long run, proves expensive. It is cheaper
after all to drain the breeding places, as they then require very
Drainage has become more popular in recent years and large
areas, that it would have been thought foolish to attempt to
drain a few years ago, have been successfully drained. Perhaps
the most extensive work has been done in the New Jersey salt
marshes by Dr. J. B. Smith (Smith 1901-1911). Salt marsh
mosquitoes are long distance flyers (forty miles in some cases)
and large areas had to be drained to control them. Something
of the magnitude of the work in general is gathered from the
following figures. Up to 1911, about thirty thousand acres had
been drained and nearly four million feet of ditches dug at a cost
of about $75,000 (Smith 1911). Wherever this work has been
done, the mosquitoes are practically eliminated and it has proved
successful in every way. This work has been accompanied by
considerable oiling, as is usually the case, to give immediate re-
lief, and in some places where it was not practicable to drain.
Numerous other cases of the eradication of these pests and
the diseases they carry, by these remedial measures are on record.
Prior to 1905, a house to house inspection showed that twenty
per cent of the population in some parts of Staten Island were
suffering from malaria. Anti-malaria work was undertaken,
and in 1909 there were only five cases of malaria reported (How-
ard 1910). Dr. E. P. Felt (1905) states that Lawrence, Long
Island, has been freed from the salt marsh mosquitoes. H. J.
Quayle (1906) reports some very satisfactory work against the
salt marsh mosquito near San Francisco. The Lawrence, L. I.,
Board of Health (1903) has done good work which has rid their
town. Havana, Cuba, has been cleared of yellow fever and made
habitable by anti-mosquito work done under direction of the
United States Medical Army Corps. The epidemic of yellow
fever in New Orleans, in 1905, was stamped out by clearing the
city of mosquitoes. Some of the most successful, as well as the
most difficult anti-malarial work, has been done in the Panama
Canal Zone. Under the French administration this was a veri-
table death trap. The tales told of the deaths are almost unbe-
THE FLORIDA BUGGIST
lievable; in fact it was difficult to keep enough men there to keep
records. When the Americans took charge, the first thing done
was to organize a Department of Sanitation to clear the zone of
mosquitoes and fever. This has been so successful that it is now
considered a health resort. Their hospital reports show (Gorgas
1913) that their monthly average of cases sent to the hospital
for malaria was only ninety-two hundredths of one per cent of
the entire force, while similar records at the University show
ten per cent.
These facts leave us no room for doubt as to the efficiency of
these methods. If Staten Island and Long Island, surrounded by
water; if New Jersey with her thousands of acres of marsh and
mosquitoes flying forty miles, and Panama with her tropical
rains and with excavations made by buildings, can be freed from
mosquitoes and malaria, why cannot most towns in Florida?
STRATEGUS WANTED-Am making a special study of this
genus, of the Scarabeidae, and should be very glad to receive
Florida specimens, especially of the rarer species. Will ex-
change or pay cash. Address W. Knaus, McPherson, Kansas.
"TESTED SEEDS FOR FLORIDA"
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