Title: Florida Entomologist
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Permanent Link: http://ufdc.ufl.edu/UF00098813/00189
 Material Information
Title: Florida Entomologist
Physical Description: Serial
Creator: Florida Entomological Society
Publisher: Florida Entomological Society
Place of Publication: Winter Haven, Fla.
Publication Date: 1960
Copyright Date: 1917
Subject: Florida Entomological Society
Entomology -- Periodicals
Insects -- Florida
Insects -- Florida -- Periodicals
Insects -- Periodicals
General Note: Eigenfactor: Florida Entomologist: http://www.bioone.org/doi/full/10.1653/024.092.0401
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Bibliographic ID: UF00098813
Volume ID: VID00189
Source Institution: University of Florida
Holding Location: University of Florida
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Volume 43, No. 2 June, 1960

Christie, J. R.- Some Interests Entomologists and
Nematologists Have in Common ---.....---............................. 43
Simanton, William A.-Seasonal Populations of Citrus
Insects and Mites in Commercial Groves --....---................. 49
King, John R., M. Cohen, and R. B. Johnson-Film-Forming
Sprays on Citrus in Florida ------- --..... ..................... ........-...... 59
Genung, William G.-Comparison of Insecticides, Insect
Pathogens and Insecticide-Pathogen Combinations for
Control of Cabbage Looper Trichoplusia ni (Hbn.) ...---.. 65
Wilson, John W.-The Performance of DDT for Corn Ear-
worm Control Over an Eleven Year Period .-.................... 69
Anthony, Darrell W.-Tabanidae Attracted to an Ultra-
violet Light Trap ...-----..... .............................. 77
Denmark, H. A.-Some Observations on the Biology of
Anchylopera platanana Clemens (Lepidoptera,
Olethreutidae) in Florida ..----------.----... .........-....... 81
Hughes, Idwal Wyn-Some Natural Enemies of the White
Peach Scale, Pseudaulacaspis pentagon (Targioni)
(Homoptera: Coccoidea) in Florida ....................-----------. 89
Hussey, Roland F.-A Lygaeid New to the United States
List (Hemiptera) ....................------------------............... 93
Obituary-Joseph William Decker .-...........--------------............ 93
Index to Volume 42, The Florida Entomologist ......-............. 99

Published by The Florida Entomological Society


OFFICERS FOR 1959-1960

President -------.......-..... --------...............-...-......Andrew J. Rogers
Vice-President............-.....--........ .............-....-...--... Lewis Berner
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Nematologist, Florida Agricultural Experiment Station

Insects and nematodes have been living together in close association
for a long time. Many intimate interrelationships have evolved. Among
these relationships are some of the most interesting and amazing examples
of biological adaptation that occur anywhere in the field of zoology. This
is not surprising. These relationships have been evolving over a vast
period of time. There were nematode parasites of insects long before there
were nematode parasites of vertebrates, or any vertebrates to parasitize
for that matter. Speaking phylogenetically, the parasites of insects include
what are, without much doubt, the oldest nematode parasites known. Com-
pared with these the parasites of vertebrates are rank newcomers to a
parasitic mode of life. Many of the parasites of plants have become adapted
to parasitism rather recently, but not all. Some of these are obviously old.
I shall endeavor to discuss with you some of these interrelationships
between insects and nematodes. I cannot begin to cover them all. The best
I can do is make a few general remarks and select a few examples. Some
of the examples selected represent extremes, that is the end products of
evolutionary adaptations. Many of the intermediate steps are known.
Nematodes of the families Rhabditidae and Diplogasteridae are pre-
eminently scavengers living in dung or in decaying organic matter of
one kind or another. Rhabditis coarctata, for example (9), lives in dung.
As long as the dung is fresh and moist, this nematode reproduces rapidly
and builds up enormous populations. When the dung begins to get old
and dry, larvae by the thousands climb to the tops of upward pointing
projections. Here they become attached by their tails and wave their
bodies about like a miniature field of grain. Hundreds of these larvae may
be wiped off and stick to the first dung beetle that happens to come walking
by. After all, what better way of getting to some fresh dung than to
thumb a ride on a dung beetle.
The hookworms, parasites of man, dogs, cats, and some other animals,
are skin penetrators. They enter their hosts by penetrating the skin,
migrating into the lymphatics and thence to the blood stream. Eggs hatch
in fecal-contaminated soil. Newly hatched larvae climb to the tops of
upward pointing projections. Here they become attached by their tails
and wave their bodies about in anticipation of being wiped off, not in this
case by a passing insect, but by the proverbial barefoot boy or by his dog.
The rhabditids are the closest living relatives of the ancestors of the hook-
worms. Early-stage hookworm larvae look so much like the early stages of
many rhabditids that parasitologists have difficulty in telling them apart.
It is my contention that when parasitologists are watching the behavior
of hook worm larvae that results in skin penetration they are looking at a

1A paper presented to a joint meeting of the entomologists and nema-
tologists of the Florida Agricultural Experiment Stations at Gainesville,
January 8, 1960.

44 The Florida Entomologist Vol. 43, No. 2

fragment of history, a behavior pattern evolved long ago that enabled the
ancestors of the hookworms to be disseminated by insects.
Back in the days when vinegar was made, not by the chemist, but by
the fermentation of apple juice "down by the wineger works," the vinegar
eel was a first-class nuisance. Not that it caused any public health hazard,
it merely added a little protein to the vinegar. But people objected to
having eelworms in their vinegar and, unfortunately, the vinegar eel is
a moderately large nematode not too difficult to see. Precautions that
seemed adequate to keep the vinegar eel out all too frequently failed.
When the puzzle was solved the solution was very simple. The nematode
was being disseminated by fruit flies of the genus Drosophila. While the
precautions may have been adequate to keep out the vinegar eel, they were
not adequate to keep out the fruit flies.
When Cobb (3) was investigating the red ring disease of coconutpalms,
he found that the causal organism, the coconutpalm nematode, was being
disseminated by the palm weevil, Rhyncophorus palmarum. Snyder and
Zetek (8) reported one instance where this same nematode was being
carried from diseased to healthy palms by termites. Fenwick (6), who
is at present engaged in investigating the red ring disease in Trinidad,
is inclined to doubt the importance of the palm weevil as a vector, but he
does not deny that dissemination in this manner may occur.
I have selected the two last-mentioned examples of dissemination of
nematodes by insects largely because they have an economic slant. Let
us now turn to the scavengers and to associations between these and insects
of an entirely different kind.
If you should undertake to dissect miscellaneous insects and examine
them for nematodes, you would be likely to find, in the intestine, small
immature forms. These would be found in many different kinds of insects
but never in large numbers, usually only one, at the most only a few.
They would all be in about the same stage of development, so immature
that it would be difficult to identify them, even to family. These larval
nematodes remain passively in the intestine without maturing and appar-
ently without causing the insect any harm. But when the insect dies or
is killed, these nematodes mature and reproduce rapidly in the decaying
Some of the nematodes of this general group are not so innocuous.
Becoming impatient of waiting until the insect dies of other causes, they
have developed a method whereby they can hasten matters along. This
is accomplished, so we are told, by a bacterium, carried in by the nematode
that kills the insect. Neoaplectana glaseri belongs in this category. You
are all familiar, no doubt, with the work of Glaser (7) and his colleagues
in their endeavors to use this nematode as an agent for controlling the
Japanese beetle, Popillia japonica. They studied its life history and habits
in detail and developed methods for rearing it on a large scale with arti-
ficial media. Their efforts to control the Japanese beetle on a field scale
by inoculating the soil with this nematode met with some measure of suc-
cess. We might have heard more about this method had not the milky
disease seemed to be somewhat more effective and easier to handle. Fur-
thermore, it may have been easier to sell the idea of controlling an insect
with a bacterial disease than of controlling it with a nematode.

Christie: Some Interests in Common

Dutky and Hough (5) experimented with a related species of Neoa-
plectana obtained originally from infected codling moth larvae, Carpocapsa
pomonella, collected in Virginia. In the laboratory they found the nema-
tode capable of producing fatal infections in many insects, including the
European corn borer, Pyraustia nubilalis; the armyworm, Pseudaletia uni-
puncta; the tobacco moth, Ephestia elutella; a sawfly, Neodipyrion sp.;
and several others. The nematodes for these experimental inoculations
were obtained by rearing in larvae of the wax moth, Galleria mellonella.
A press release relating to this work mentioned tests with disseminating
the nematodes through spray nozzles in the routine application of sprays.
More recently, Welch (10) reported results of trials with this same
nematode for controlling the Colorado potato beetle, Leptinotarsa decem-
lineata. Nematodes suspended in water were applied with a hand sprayer.
In spite of rains following application that may have washed off many of
the nematodes, enough beetles and larvae became infected to reduce the
insect population by about 35 percent.
Although species of Neoaplectana and other nematodes that have simi-
lar habits are usually referred to as parasites, they are primarily scaven-
gers. Now let us direct our attention to some nematodes that are, in fact,
true parasites of insects. It should be noted, at this point, that many of
the nematode parasites of man and of domesticated animals use an inter-
mediate host as a means of gaining entrance to their final or definitive host.
All species of the superfamilies Spiruroidea and Fliarioidea, as well as
some members of other groups, have intermediate hosts in their life cycles.
The transmission of filariasis by mosquitoes is a matter of common knowl-
edge. Most of these intermediate hosts are arthropods, many of them
insects. These do not concern us in the present discussion, but I mention
them in passing to help round out the picture.
Most of the parasites of insects can be divided into two groups, those
found in the intestine and those found in the body cavity. The parasites
of the intestine have very simple life cycles and are not outstandingly
different from many other nematodes. The parasites of the body cavity
have complicated life cycles and are outstandingly different from all other
nematodes. The body-cavity parasites that I will discuss are of two fam-
ilies, the Mermithidae and the Allantonematidae.
The mermithids are a large group; there are many species. They are
preeminently, though not exclusively, parasites of arthropods, mostly in-
sects. They have been reported from more different kinds of insects than
any of the other groups of nematode parasites. Through the work of
Wheeler (11), entomologists are perhaps most likely to know about the
parasites of ants. A mermithid does queer things to the development of
casts in ants, some of the parasitized individuals being intermediate be-
tween queens and soldiers or between soldiers and workers, and some not
resembling any normal cast. The so-called cabbage hairworm has been seen
so frequently on heads of cabbage, and so many inquiries were received
about it, that the U. S. Department of Agriculture once published a cir-
cular explaining what it is and reassuring people that it is not dangerous
to man. Obviously, it is a parasite of some insect that feeds on cabbage,
but which one, so far as I know, has never been determined. The two

46 The Florida Entomologist Vol. 43, No. 2

species whose life cycles are the most completely known are parasites of
grasshoppers. These are Agamermis decaudata and Mermis subnigrescens.
Agamermis decaudata (1) is a common parasite of grasshoppers in Vir-
ginia and, no doubt, in other parts of the upper South. Briefly, its life
cycle is this: The fully-grown but sexually-immature parasites force their
way out their grasshopper hosts sometime during late summer or early
autumn, fall to the ground, and enter the soil. Here they reach sexual
maturity, copulate, and lay eggs. Females that emerge from their hosts
one year will reach maturity and be laying eggs the following spring at
the time grasshopper eggs are hatching. Newly hatched mermithid larvae
migrate to the surface of the soil and climb grass and other low vegetation
when it is wet with dew or rain. Here they seek and enter newly hatched
grasshopper nymphs by penetrating the body wall.
These preparasitic larvae of Agamermis are remarkable organisms.
They are about 5 mm. long, very slender, and exceedingly active. The
body is divided into two sections by a node. The anterior section contains
all the usual organs but is only about one-fifth the total length. The re-
maining four-fifths is a food storage and propelling organ. During the
process of penetrating the host, the body breaks at the node and this
propelling organ is discarded and remains on the outside.
Mermis subnigrescens (2) is a common parasite of grasshoppers through-
out New England and at least as far west as Wisconsin. Its life cycle is
essentially the same as that of Agamermis decaudata with one important
difference. Females do not lay their eggs in the soil. Instead they come
to the surface and lay their eggs on low vegetation during spring rains.
The eggs are provided with entangling appendages for attachment to the
foliage. In the case of Agamermis, which grasshoppers acquire while
they are young nymphs, the usual condition is one parasite per host. In
the case of Mermis, which grasshoppers can acquire at any time while
feeding, one host frequently harbors a considerable number and they may
be of different ages.
The effect of mermithids on grasshoppers is to retard the development
of the reproductive organs and render the insects sterile. Agamermis,
which is always acquired while the insect is very young, will invariably
render a female grasshopper sterile. Mermis will usually render a female
sterile but whether or not will depend on the number of parasites and,
more especially, the age of the insect when they were acquired. The
effects of these parasites on the male grasshopper is the same as their
effects on the female but tends to be somewhat less pronounced. Mer-
mithids always kill their hosts when they emerge to enter the soil.
Some of you will be raising the question as to whether or not mermithids
do, in fact, have any appreciable effect in holding grasshopper populations
in check. No one can answer this question and support his answer with
precise data. The best one can do is express an opinion based on field
observations and such other information as is available.
During August 1930, collections were made in 83 fields, most of them
in the Merrimack and Connecticut River valleys of New England. In each
field, 100 grasshoppers were collected and examined. The percentage har-
boring mermithids was as follows:

Christie: Some Interests in Common 47

1 field .................. .. ..-- .-. 80%
2 fields .....-............-- ....-.......... 50 to 59%
3 fields ---... .....-- ........... ----- 40 to 49%
7 fields .........--- ~.-- .... ....--- ---... 30 to 39%
11 fields --..........-- -----.-.. -- .... 20 to 29%
19 fields .--.. -------.......---...-..-.. 10 to 19%
30 fields .- --.. -.................-----. 1 to 9%
10 fields ... ............------------.. None
Average ..--.----........---.......-....---- 12%
I think all who were engaged in these investigations came to the con-
clusion that mermithids do exert a very great influence in suppressing
grasshopper populations. It may be more than coincidence that serious
grasshopper epidemics rarely occur in regions where mermithids are known
to be present. The weak point in the life cycle of both these species of
mermithids is that it can be completed (i.e., grasshoppers become infected)
only where climatic conditions provide periods when there is dew or rain.
Frequently, it is possible to control a pest by taking advantage of a weak
point in its life cycle. By the same token, a weak point in the life cycle
may limit the usefulness of a parasite as an agent in biological control.
Now let us direct our attention to one example of that other group of
body-cavity parasites, the Allantomatidae. Fergusonina is a genus of flies
that cause galls on Eucalyptus trees. There are many species of this genus
in Australia, and the parts of the trees where the galls are formed differs
with the species. Each species of fly is believed to live in association with
a nematode, though probably not the same species of nematode. The fly
used in the study of this association (4) was Fergusonina nicholsonia, and
it causes galls in the flower buds. The associated nematode was named
Fergusobia curriei.
The fly deposits its eggs on the flower buds and with each egg it deposits
from 1 to 50 nematode larvae. The same fly, or different flies, may lay
several eggs in one bud. The larval nematodes begin to feed on the anther
primordia that forms a ring of cells at the base of the bud cavity. The
cells respond in exactly the same way that many plant tissues respond
to the feeding of plant-parasitic nematodes. They begin to divide and
form a mass of large, thin-walled, parenchymatous cells filled with a
mucilaginous sap. The nematodes, feeding on this plant tissue, mature
into females and pass through several parthenogenetic generations.
While all this is going on, the eggs of the fly hatch, after about six
days, and the fly larvae move into the mass of parenchymatous tissue and
form cavities. Here they proceed in their development, feeding on the
mucilaginous sap that oozes from the ruptured plants cells. As the fly
larvae complete their development, but before they pupate, the nematodes
suddenly produce a generation composed of both sexes. These quickly
reach sexual maturity, copulate, and the males die. Two, and only two,
of the impregnated female nematodes enter the body cavity of each female
fly larva by penetrating the body wall. Fly larvae destined to become
males are never invaded, females invariably. In the body cavity, the
nematodes grow rapidly and undergo the same kind of parasitic degener-
ation that is characteristic of most allantomatids. They become little
more than sacks filled with the reproductive organs.

48 The Florida Entomologist Vol. 43, No. 2

Eggs are deposited and hatch in the body cavity of the insect. The
resulting nematode larvae migrate into the female goniduct and assemble
at the posterior end. From here they will be extruded with the eggs when
the fly starts ovipositing on the buds of Eucalyptus trees.
Those who have studied this association are inclined to regard the
stages of the nematode that occur in the galls as true plant parasites, but
the relationship with the gall flies as symbiosis. While they do not say
in so many words that the fly could not exist without the nematode, their
comments seem to carry this implication.
I would like to point out, in closing, that these interrelationships be-
tween insects and nematodes have been studied by only a few investigators.
For the most part, they are associations that these investigators stumbled
onto by accident. I feel sure the ones we know about represent but a small
fraction of the ones that exist.


Christie, J. R. 1936. The life history of Agamermis decaudata, a nema-
tode parasite of grasshoppers and other insects. Jour. Agr. Res.
52 (3) : 161-198.
Christie, J. R. 1937. Mermis subnigrescens, a nematode parasite of
grasshoppers. Jour. Agr. Res. 55 (5): 353-364.
Cobb, N. A. 1919. A newly discovered nematode, Aphelenchus cocophilus
n. sp. connected with a serious disease of the coco-nut palm. W.
Indian Bull. 17 (4): 203-210.
Currie, G. A. 1937. Galls on Eucalyptus trees. A new type of association
between flies and nematodes. Proc. Linn. Soc. N. S. Wales 62 (3-4):
Dutkey, S. R., and W. S. Hough. 1955. Note on a parasitic nematode from
codling moth larvae, Carpocapsa pomonella. Proc. Ent. Soc. Wash.
57 (5) : 244.
Fenwick, D. W. 1957. Red ring disease of coconuts in Trinidad and
Tobago. Report. London. Colonial Office, 55 pp.
Glaser, R. W., E. E. McCoy, and H. B. Girth. 1940. The biology and eco-
nomic importance of a nematode parasitic in insects. Jour. Parasitol.
26 (6): 479-495.
Snyder, E. T., and J. Zetek. 1924. Damage by termites in the Canal Zone
and Panama and how to prevent it. U. S. Dept. Agr. Bull. 1232.
Triffitt, Marjorie J., and J. N. Oldham. 1927. Observations on the mor-
phology and bionomics of Rhabditis coarctata Leuck. occurring on
dung beetles. Jour. Helminth. 5 (1): 33-46.
Welch, H. E. 1957. Test of a nematode and its associated bacterium for
control of the Colorado potato beetle, Leptinotarsa decemlineata
(Say). Ann. Rept. Ent. Soc. Ontario 88: 53-54.
Wheeler, W. M. 1928. Mermis parasitism and intercasts among ants.
Jour. Expt. Zool. 50 (2) : 165-237.


University of Florida Citrus Experiment Station, Lake Alfred

Populations of the major insects and mites that affect citrus are known
to vary from month to month as each species passes through its life cycle
and responds to environmental changes. Also well recognized is the variation
in abundance of a major insect or mite pest from year to year.
In the case of minor citrus pests, fluctuations in population are less
well known because these species usually have been studied only in limited
areas and mainly during outbreak years.
Very little information on the range of population sizes in Florida
groves has appeared in the literature. The purpose of this paper is to
present population data obtained from observations made each month from
1951 through 1958. These data, taken from 130 representative groves,
reflect the influence of natural ecological factors plus the effects of pest
control practices used in a majority of groves.
The population records obtained have been used to express the average
abundance of 19 citrus pests throughout the Florida citrus belt during
each month of the year. By utilizing records of maximum and minimum
populations that occurred in the 8-year period, it has been possible to
delimit a probable range of fluctuation for a number of species. Although
it is not the intention in this paper to dwell upon factors that cause popula-
tion changes, some comments are included regarding unusual populations
that followed the cold winter of 1957-58.

Populations were determined each month over a period of eight and
and a half years from January 1951, through July 1959, for the following
citrus pests:
Citrus rust mite, Phyllocoptruta oleivora (Ashm.)
Purple scale, Lepidosaphes beckii (Newm.)
Citrus red mite, Panonychus citri (McG.), commonly called
purple mite in Florida.
Black scale, Saissetia oleae (Bern.)
Red scale, Chrysomphalus aonidum (L.)
Texas citrus mite, Eutetranychus banksi (McG.)
Whiteflies in populations consisting of one or more of the
following species: cloudy-winged whitefly, Dialeurodes
citrifolii (Morg.); citrus whitefly, D. citri (Ashm.);
wooly whitefly, Aleurothrixus floccossus (Mask.)
Citrus mealybug, Pseudococcus citri (Risso)
Soft scale, Coccus hesperidum L., also known as soft
brown scale.
Aphids in populations comprising one or more of the follow-

1 Florida Agricultural Experiment Station Journal Series, No. 1055.

50 The Florida Entomologist Vol. 43, No. 2

ing species: citrus or spirea aphid, Aphis spiraecola
Patch; cotton or melon aphid, Aphis gossypii Glov.;
black citrus aphid, Toxoptera aurantii (Fonsc.)
Six-spotted mite, Eotetranychus sexmaculatus Riley
Chaff scale, Parlatoria pergandii Comst.
Florida wax scale, Ceroplastes floridensis Comst.
Glover's scale or long scale, Lepidosaphes gloverii (Pack.)
Yellow scale, Aonidiella citrina (Coq.)
Cottony cushion scale, Icerya purchase Mask.
Fern scale, Pinnaspis aspidistrae (Sign.)
Dictyospermum scale, Chrysomphalus dictyospermi (Morg.)
Citrus snow scale, Unaspis citri (Comst.)

This study was part of a continuous survey of ecological factors affect-
ing citrus production, conducted under Florida Agricultural Experiment
Station Project 606. The procedures used in this project that pertain to
these population studies were as follows:
One hundred and thirty groves were selected throughout the Florida
citrus belt to represent as proportionally as possible the acreage, varieties,
rootstocks, spray programs, and weather conditions that prevail in the
commercial citrus producing area. Approximately 13 per cent of these
groves received little or no pesticidal treatment, whereas the majority
were on a fairly complete pest control program.
Five trees representative of each grove were tagged as count trees.
Except in a few cases where it was necessary to substitute another grove
or to change from trees that became atypical within a grove, the same trees
were always observed.
Populations of purple and red scales were determined by examining
under a microscope both surfaces of the basal quarter of 50 leaves from
each tree and recording the percentage of leaves infested with living scales.
Black scale was determined by observing 12 inches of twig nearest the
stem on 10 fruiting terminal twigs per tree using 2X magnification. The
percentage of infested terminals was recorded.
Citrus red (purple) mite, Texas citrus mite, and six-spotted mite popu-
lations were determined by examining 20 leaves per tree with 2X magni-
fication and recording the number of leaves infested with each species.
Rust mite populations were obtained from an examination of 20 leaves
with a 10X hand lens. If a mite was seen in two lens fields, one on each
surface of the leaf, the leaf was counted as infested.
Populations of minor pests were estimated from a 5 minute gross in-
spection of each tree and from the number of individuals seen during the
detailed examination for major pests. Extent of infestation was recorded
as class 0, 1, 2, or 3, indicating respectively no infestation, very light in-
festation, light to moderate infestation, and moderate to heavy infestation.
In general, class 2 indicated an infestation of 5 to 19 percent of the twigs,
fruit, or leaves infested and classes 1 and 3 indicated lower or higher
populations. Using the classes thus assigned, a population index was cal-
culated each month for the group of 130 groves. This was done by a
weighting procedure in which the number of groves with class 1 infesta-
tion was multiplied by 1, the number with class 2 multiplied by 2, and

Simanton: Citrus Insects and Mites

20 -


Figure 1.-Average, maximum, and minimum abundance of 6 important
citrus pests each month during the 8-year period from January, 1951,
through December, 1958. The data are from 130 representative citrus
groves throughout the Florida citrus belt. An asterisk in the graphs marks
the change to observations on spring flush leaves.


r2 _- -
"I -.-- ... ---'-- --.-.-.-" "- -

52 The Florida Entomologist Vol. 43, No. 2

the number with class 3 multiplied by 3. The resulting weights were
summed and then divided by the total number of groves examined (130) to
arrive at the numerical value for population index.

The average, maximum, and minimum populations that occurred each
month from January 1951 through December 1958 are presented graphically
in Figures 1 4. Texas citrus mite data, however, are only for the period
from July, 1954, through December, 1958. In each chart the solid central
line shows the mean of 8 statewide populations observed in each of the
12 months during 8 years. The upper and lower broken lines show the
highest and the lowest of the 8 observations.
The graphs are arranged in the same order as the species listing pre-
sented earlier in the paper. This arrangement, headed by rust mite, is
approximately in descending order of average abundance of the species
in commercial groves throughout the year as determined by survey pro-
cedures. Thus, all of the graphs have a numerical relationship. The
first six species (Fig. 1) are those against which chemical control measures
are usually directed and thus are subjected to a more detailed count.
Populations of these six principal pests are expressed as percentage of
leaves or twigs infested, whereas abundance of the other species is ex-
pressed as population index. The data for Texas citrus mite are presented
twice, in Fig. 1 as percent leaves infested and in Fig. 3 as population index,
to point out the close similarity of the two methods in portraying the
seasonal changes.
It should be emphasized that the order of abundance of a species as
indicated in this listing is not necessarily its order of importance from
an economic standpoint. For example, black scale seldom causes serious
losses whereas red scale, which often shows a lower degree of infestation
over the state, can build up rapidly in individual groves and cause severe
Weather during the 1951 through 1958 period was probably as typical
as for any 8-year period. It included two "dry" years in succession, 1955
and 1956, two "wet" years, 1953 and 1957, and unusually low temperatures
in the winter of 1957-58.
The major value of the graphs is that they provide for the first time
a measure of "normal" population and delimit a range against which a
current population can be evaluated. This is an important aid in the
forecasting of citrus pest abundance for control purposes and in studying
the effects of weather and other ecological factors responsible for fluc-
tuations. Certain lesser citrus pests are not included in this presentation;
among them are pyriform scale, grasshoppers, katydids, pumpkin bugs,
and various leaf-feeding worms and beetles.
One phenomenon of interest from a biometric standpoint is the location
of the mean population line with respect to the midpoint of the range.
Where the mean and midpoint are close together, as is the general situ-
ation in all of the 20 graphs, the yearly populations were distributed quite
uniformly above and below the mean. Where this is not the case, one limit
of the range usually was the result of a highly abnormal population that
occurred in only 1 of the 8 years. On the whole, the cycles of rise or decline

Simanton: Citrus Insects and Mites





. .. \


N .-I


- --


J J A S 0

Figure 2.-Average, maximum, and minimum abundance of whitefly
larvae, mealybug, and soft brown scale each month during the 8-year period
from January, 1951, through December, 1958. The data are from 130
representative citrus groves throughout the Florida citrus belt.





x 1.00
0 .60


.60 r


.40 F


.20 -



a .10







Vol. 43, No. 2

Figure 3.-Average, maximum, and minimum abundance of aphids,
Texas citrus mite, six-spotted mite, and chaff scale each month during the
8-year period from January, 1951, through December, 1958. The data are
from 130 representative citrus groves throughout the Florida citrus belt.

a i

The Florida Entomologist



r ~ -0




Simanton: Citrus Insects and Mites

followed a remarkably similar pattern from year to year. The charts show
that each pest has a distinctive cycle which is related to seasonal weather
factors and to the growth condition of the host.
Of particular note is the number of species that rather consistently
decline to a low level at or near September. Aphids are an exception to
this generalization, apparently because their abundance is related to
spring and fall flushes of new growth. In the case of whiteflies, the graph
shows considerable variability in early fall. At least 3 species of whiteflies,
often intermingled, make up the respective infestations reported here and
considerable overlapping of broods occurs.
Chaff scale, and to some extent soft brown scale, differ from other
scales reported in that their populations decline markedly only during the
summer months.
Rust mite, Texas citrus mite, chaff scale, soft brown scale, and fern
scale are species that tend to be abundant in late fall as well as at other
times of the year. Seasonal information on the Texas citrus mite is of
particular interest because of the spread and increase of this species since
it was first reported as a citrus pest in 1953 (Muma et al., 1953). The
fact that each ensuing year has produced higher populations of this mite
implies that future populations may cover a range quite different from that
charted through 1958.
Although a period of eight, reasonably representative years may be
considered to provide a fair measure of average population levels, it is
obvious that the range from maximum to minimum will increase as more
years are included in the record. Several notable changes in citrus insect
and mite populations occurred in 1958 and in the first half of 1959. These
are mentioned specifically in the paragraphs that follow to augment the
graphic information.
The purple scale graphs are of special interest because they show that
populations of this important citrus pest were always at a relatively high
level and did not fluctuate greatly during the 8 years prior to 1959. How-
ever, beginning in January, 1959, this species dropped far below the mini-
mum line shown in Fig. 1 and by August, 1959, less than 2 percent of
leaves were infested. This extreme reduction in population of a major
pest of long standing is believed due to parasitism by Aphytis lepidosaphes
Compere, which was first noted in Florida groves in 1958 (Muma and
Clancy, 1959). Should this parasite continue to be effective in future
years, this scale may become much less important. Graphs of purple scale
abundance based on the next few years are not likely to resemble those
presented here.
Following the unusually cold winter of 1957-58, red scale, purple scale,
black scale, citrus red mite, mealybug, and aphid populations were greatly
reduced for 2 to 4 months. Much of this effect was a direct result of
defoliation of the host. During the late winter and through the spring
of 1958, red scale, yellow scale, and mealybug populations were at the
minimum points shown on the charts for that period. In this same period,
a new maximum was set for chaff scale.
Six-spotted mite also established a new maximum for May and June,
1958. This was expected, since high populations of this mite are favored
by cold weather in the preceding December (Pratt, 1955).

The Florida Entomologist

Vol. 43, No. 2



I I i |I I- i i- i- -

.40 '--

.30 /

-0 -^ --- /' -1

I ---------------"------

30 ------
20 -

.10 .7

.05 -
01 / ... --Z -- --


.05 F



.05- .


0= -c c- c ; c- _- ; -- t : :


Figure 4.-Average, maximum, and minimum abundance of 7 minor
scale pests of citrus each month during the 8-year period from January,
1951, through December, 1958. The data are from 130 representative citrus
groves throughout the Florida citrus belt.


Simanton: Citrus Insects and Mites 57

It was expected that effects of the cold would extend for many months
and this was confirmed early in 1959 when populations of red scale and
black scale exceeded the maximums shown by the graphs which were estab-
lished during the preceding 8 years.


Populations were determined each month for 19 species of citrus pests
in 130 typical commercial groves. The maximum, minimum, and average
populations for each month were established by 8 years of observation
from 1951 through 1958. These are presented graphically. For many
pests, the graphs depict for the first time a measure of "normal" abund-
ance and delimit a probable range of fluctuation.
Each pest exhibited a distinctive cycle of abundance through the season
which was repeated with considerable regularity each year. A majority
of species reach a high population in early summer and then decline to
a low level at or near the month of September. Chaff scale and soft scale
decline markedly only during the summer. Rust mite, Texas citrus mite,
chaff scale, soft brown scale, and fern scale are species that tend to be
abundant in late fall as well as at other times of the year.
Texas citrus mite, first observed as a citrus pest in 1953, has become
more abundant in each succeeding year. Purple scale populations during
early 1959 were far below the minimum of previous years, apparently due
to activity by a new parasite, Aphytis lepidosaphes Compere.
Populations of 6 pest species were reduced for 2 to 4 months following
the unusually cold winter of 1957-58. Six-spotted mite rose to abnormally
high levels during May and June 1958, as expected. Red scale and black
scale populations exceeded previous maximums in the first half of 1959.


The author wishes to acknowledge with thanks the participation of
J. W. Davis, J. K. Enzor, Jr., E. D. Harris, Jr., T. B. Hallam, H. I. Holts-
berg, R. M. Pratt, L. M. Sutton, K. G. Townsend, and J. B. Weeks in ob-
taining the population data included in this paper.

.JtnIa, Martin H., Harold Holtsberg, and Robert M. Pratt. 1953.
Eutetranychys banksi (McG.) recently found on citrus in Florida
(Acarina: Tetranychidae). Fla. Ent. 36(4): 141-144.
Muma, Martin H., and D. W. Clancy. 1959. A purple scale parasite new
to Florida citrus. Citrus Magazine 21(8): 18.
Pratt, Robert M. 1955. The purple mite and six-spotted mite situation
in 1955. Proc. Fla. State Hort. Soc. 68: 31-36.


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Florida Citrus Experiment Station, Lake Alfred

During recent years, chemists, entomologists and plant pathologists
have developed effective pesticides from practically all known types of
toxic chemicals in both organic and inorganic groups. However, there
have been few attempts to determine the value of non-toxic physical barriers
applied as coatings for plant protection. The possibility of using materials
that are low in toxicity to people as well as insects is especially interesting
at this time, when public health authorities are introducing increasingly
strenuous controls against the use of highly toxic materials on crops.
The purpose of this study was to determine whether a mechanical film
would protect citrus plants from citrus rust mite, Phyllocoptruta oleivora
(Ashm.), and greasy spot disease.
Since 1955 various plastic, synthetic latex and wax materials, commonly
used in industry for paints, binders and water-resistant coatings, have
been applied as sprays to determine filming characteristics and effects on
citrus plants. Formulations were non-toxic milky-white, aqueous emulsions
containing about 50 percent solids. Other characteristics were a particle
size of less than 1 micron, a specific gravity of about 1 and pH ranging
from less than 3 to more than 9. All of the materials tested mixed with
water in all proportions and dried to solid films that would not go back
into suspension upon subsequent wetting with water.


Formulations of polyethylene, acrylic resin, vinyl acetate, wax, poly-
vinyl alcohol, hydroxyethyl cellulose and other similar materials were ap-
plied to fruiting branches. All materials were applied with a compressed
air hand sprayer at concentrations of 10 percent of each formulation in
Polyethylene formulations were the only phytotoxic materials at con-
centrations tested. Film deposits of Elvacet, Resin latex WC-130, Plyac,
General Chemical Experimental Sticker, General Chemical synthetic wax
dispersion and Acetex 2700 became hard and brittle after drying thoroughly.
Fruit and foliage coated with Resyn 12-K-55, Rhoplex AC-33, Rhoplex B-15
and Hercuies AC-7356 were glossy and the film remained flexible for
several months.
In addition to tests with fruiting branches, three types of materials
were applied to mature Valencia orange trees. The materials used were:
Rhoplex B-15 (Acrylic resin), Plyac (polyethylene) and a suspension of
wax. Each material was applied at 21/ percent, 5 percent and 10 percent
with a hydraulic grove sprayer operating at about 500 psi. The first
application was made in June and a second spray was applied to one-half
of each tree in October.
Sprays containing 5 percent or 10 percent polyethylene were phytotoxic
to fruit when applied in June, but not in October. The injury produced

1 Florida Agricultural Experiment Station Journal Series, No. 1057.

60 The Florida Entomologist Vol. 43, No. 2

was similar to russet caused by citrus rust mite. Good wetting was ob-
tained with the polyethylene spray and a fairly good film was deposited
with both concentrations, but the film did not cover the entire fruit and
leaf surface and began to weather off after about three months. Applica-
tions of wax were not phytotoxic, but began to flake off after about six
weeks. Rhoplex B-15 at all concentrations gave a good film which remained
pliable for about one year, gave the tree a glossy appearance and appar-
ently had no harmful effect on tree vigor. These results governed the
selection of Rhoplex for more extensive replicated trials against specific
citrus problems.

In 1958, Rhoplex AC-33 was compared with miticides against rust mite
on grapefruit at Fort Pierce and on oranges at Lake Alfred. It was also
compared with miticides and fungicides at Fort Pierce for control of
greasy spot disease on grapefruit and oranges.
In all experiments, applications were made with a hydraulic grove
sprayer equipped with hand guns. Sprays were directed to all parts of
the tree and applied to the point of run-off to obtain thorough coverage.
The density of rust mite populations was determined at Fort Pierce
by examination of one lens field, with a 10X hand lens, on each surface
of 100 leaves in each replicate. Exposed and unexposed surfaces of 25
fruit per plot were examined for rust mite in a like manner at Lake
Alfred. If one or more live mites was found, the leaf or fruit was con-
sidered infested. Russet fruit determinations were made by examining
10 fruit per tree at Fort Pierce and 25 fruit at Lake Alfred.
The severity of greasy spot disease in the Fort Pierce rust mite experi-
ment was determined by examination of 100 leaves per plot in the follow-
ing manner: the third leaf from the terminal of current season branches
was picked from 25 locations per tree and the severity of disease rated
according to the number of lesions per leaf. Ratings consisted of 0, 1,
2 and 3 with 0 representing no lesions, 1 representing 1 to 5 lesions, 2
representing 6 to 15 lesions and 3 representing 16 or more lesions.

In the Fort Pierce rust mite experiment, the percentage of leaves in-
fested with rust mite increased after treatment in check plots, plots sprayed
with Rhoplex and in some of the plots sprayed with sulfur, but decreased
for at least 21 days after other treatments. However, observations showed
that the number of mites on check plants increased in proportion to the
percentage of infested leaves. This was not so on Rhoplex-sprayed plants.
The Rhoplex film was not continuous over the entire fruit surface and
mites were present only in the uncovered areas. Furthermore, the number
of mites per lens field on uncovered areas of Rhoplex-sprayed fruit was
seldom more than five, while there were usually 15 or more mites per lens
field on untreated checks.
Data shown in Table 1 indicated that Rhoplex protected fruit against
rust mite injury as effectively as zineb and was superior to sulfur. These
data also show that Rhoplex had no harmful effect on fruit color either

King: Film-Forming Sprays on Citrus 61


Percent Infested Leaves on Percent of
Indicated Dates Before Russet
and After Treatments, Fruit on Average
Materials and
ateas Applied April 28 and Dec. 17, Color
e 00 a s June 23, 1958 1958 Rating
per 100 Gallons
4/21 5/19 6/19 7/14 Early Late Before After
(-7) (+21) (+52) (+21) **

Kepone 25W, 1 lb. ...... 18 7 13 1 13 8 2.2 2.4
Rhoplex AC-33, 5%.... 17 19 39 38 0 3 2.0 1.7
Zineb 65W, 12 lb. ..-. 12 3 21 0 1 8 1.5 2.3
Ethion 47% EC,
/2 pt. --..-------.. ........... 24 12 51 38 4 3 1.7 2.0
Sulfur, 10 lbs. ........... 25 27 48 12 30 10 2.2 2.3
Sulfur, 5 Ibs. .............. 68 43 57 12 46 5 2.9 3.3
25W, 1 lb. ................ 30 10 27 3 8 5 2.4 2.3
Check ..-...-................-.... 67 90 60 13 97 10 3.9 4.0

L.S.D. 19:1 .................. 18 22 15 8 26
99:1 .......-.......... 25 30 21 11 36

* Color ratings, made before placing fruit in
Ratings based on 1 = Good and 4 = Poor;

coloring room.
ratings made by seven persons.

** Color ratings made after 72 hours in coloring room (ethylene gas).


Material and Dosage
per 100 Gallons

Percent of Leaves in Each
of the Following Groups*

0 1 2 3

Kepone 25W, 1 lb. ---..................................-- 12 55 22 11
Rhoplex AC-33, 5% ...............................-... ..... 48 37 10 5
Zineb, 65W lb. ......-............ ....-- .......-.. 21 53 15 11
Ethion 47% EC, % pt. .............. ..-............. 31 47 12 10
Sulfur, 10 lbs. .............. ......-.................... -28 45 13 14
Sulfur, 5 lbs. ..........--..........- -- ---.. .......... 22 43 15 20
Chlorobenzilate 25W, 1 lb. ...-..................... ... 18 56 15 11
Check ....------------.................. ......... ..... 11 27 22 40

0 = No lesions.
1 = 1 to 5 lesions.
2 = 6 to 15 lesions.
3 16 or more lesions per leaf.
Based on 400 leaves per treatment.

62 The Florida Entomologist Vol. 43, No. 2

before or during the period when it was degreened with ethylene gas at
the packing house.
The severity of greasy spot disease was also recorded in this experi-
ment. Data presented in Table 2 show that Rhoplex controlled greasy
spot better than any other material in this test, including zineb and sulfur.
Several mature oranges were dipped in Rhoplex emulsion concentrate
to obtain a complete film over the surface of the fruit. These fruit were
held at room temperature and compared for keeping quality with fruit
sealed in polyethylene bags and with untreated fruit. Untreated fruit
and Rhoplex-treated fruit wilted in about three weeks, while fruit sealed
in polyethylene bags remained firm for about three months.
In the Lake Alfred experiment, control of rust mite with Rhoplex was
significantly inferior to that obtained with either zineb or sulfur. Although
Rhoplex was not as effective against rust mite and did not prevent russet
as well as zineb or sulfur, it did reduce the severity of rust mite injury
to fruit as shown in Table 3.


% Percent Russet Fruit 1-15-59**
Fruit Per-
Treatment and In- cent
Dosage per tested Early Russet Late Russet Russet-
100 Gallons with Free

MRut Light Mod. Sev. Light Mod. Sev. Fruit

Unsprayed Check .. 18.1 10.6 9.4 12.4 12.0 5.0 4.0 55.4
Sulfur, 10 lbs. -.....- 12.2 5.6 3.6 3.2 5.6 0.8 0.4 83.2
Zineb, 1 lb. .-..-... 11.8 4.2 3.6 5.0 4.8 2.6 0.6 83.0
Zineb, 1 lb. ....~..-.- 11.0 1.6 1.2 1.2 2.0 0.0 0.0 95.2
Rhoplex, 2/2% ...- 19.7 7.6 6.8 10.8 10.8 5.4 4.6 59.2
Rhoplex, 5% ...-...-- 16.2 9.2 8.8 8.8 9.0 3.0 0.2 63.8
Rhoplex, 10% ..... 19.0 12.6 6.4 9.4 12.6 3.2 0.0 62.8

L.S.D. 19:1 ....... .. 2.2 2.7 2.3 4.8 2.4 1.3 0.9 9.6
99:1 ..-....- .. 2.7 3.3 2.8 5.8 3.0 1.6 1.1 12.8

Average of ten counts made from May 12 to December 30, 1958.
** Treatments applied April 21 and July 30-31, 1958.


Applications of Rhoplex AC-33 were compared with selected agricul-
tural pesticides against greasy spot disease in an experiment at Fort Pierce.
Greasy spot disease accelerates leaf drop in addition to producing
characteristic spots on the leaves. In this experiment the severity of
greasy spot disease was ascertained by rating trees for density of foliation
as well as extent of leaf spotting in a single score for tree condition. An

King: Film-Forming Sprays on Citrus 63

average rating of 1.0 or less is considered to indicate satisfactory control
of greasy spot disease.
Table 4 lists the experimental materials in general order of effectiveness.
One pound of tribasic copper sulfate per 100 gallons was the standard
treatment with which other treatments were compared. Data in Table 4
show that tribasic copper suflate, Rhoplex AC-33 and mixtures of the two
were all satisfactory. However, Rhoplex did not improve control with


Average Rating for Tree Condition*
Treatments and Dosages December 2, 1958
per 100 Gallons Sprayed April 30 Sprayed April 30,
and July 1, 1958 1958

O il 1.3% ............................. ... ............. 0.0 0.4
Oil 1.3% + Zineb 65W, 2 Ibs. ........... 0.0 0.3
Copper 53W 1 Ib. .................................... 0.1 0.2
Copper 53W, 1 lb. + Oil, 1.3% ............ 0.1 0.3
Rhoplex AC-33, 5% + Copper 53W,
1 lb. ........................---.............-......... 0.2 0.2
Rhoplex AC-33, 0.5% + Copper 53W,
1 lb. .......................... ..................... 0.3 0.5
Amobam, 1 qt. ........-..................... ...... 0.5 0.8
Rhoplex AC-33, 5% -..........---........-...... 0.7 0.7
Niacide Z 65W 2 lbs. .......-...................... 0.5 0.8
Upjohn U-9547 50W, 1 lb. .........-.....-... 0.7 0.8
Fermate 76W 2 lbs. ......-....................... 0.5 1.0
Actidione Semi-Carbazone 7.7W,
0.5 lb. .................-... .--. --.-..-- .. 0.8 1.2
Griseofulvin 38 gr. .......................... .. ----0.8 1.8
Niacide M 65W, 2 lbs. .......................-.. 1.0 1.7
Parathion 15W, 1 lb. + Sulfur WP,
5 Ibs. ... -----------......................... ..... 1.1 1.7
Thylate 65W 2 Ibs ......-..................-.. 1.2 1.5
Glyodin 34E, 1 qt. ..............................-. 1.3 1.3
Cyprex 70W 2 lbs. ....................... ....... 1.5 1.2
Actidione 4 ppm. (tablets) --.................. 1.5 1.7
Mycostatin 76 gr. .................................. 1.7 1.8
Gen. Chem. 1189, 50W, 2 lbs .............. 2.7 2.0
Check .............................-................... 2.2 2.2

Tree condition evaluated on the basis of density of foliation and amount of greasy
spot shown. Rating scale: 0 = Best tree in the plot; 3 = Poorest tree in the plot. Each
rating in the table is the average of individual ratings of at least three trees.

64 The Florida Entomologist Vol. 43, No. 2


One of the problems encountered with plastic sprays was the difficulty
of obtaining complete coverage. The success of non-toxic materials of
this type depends upon the establishment of a continuous film, a complete
barrier between the pest and its food plant. In the experiments reported
here, continuous films were not achieved. Nevertheless, sufficiently promis-
ing results were obtained to warrant further research with improved


The 43rd Annual Meeting of the Florida Entomological Society will be
held in Jacksonville at the Robert Meyer Hotel on September 8-9. A pre-
meeting "bull session" is scheduled for the evening of September 7. The
Secretary has issued a call for papers and members are reminded of the
importance of submitting titles and abstracts without delay.



The recent increased interest in the use of pathogenic agents, particu-
larly bacterial and polyhedrosis diseases, for insect control has largely
resulted in tests that compared the pathogens only with untreated checks.
A few trials included a standard insecticide treatment (Rabb et al 1957),
but investigations of combinations of pathogens and insecticides appear to
be hardly pioneered. McEwen and Hervey (1958) used an aphicide (TEPP)
with a polyhedrosis virus to observe the effect of the insecticide on the
virus. The data presented indicated that this weak larvicide did not
add to the mortality percentage obtained with the pathogen alone.
The practical use of these virus and bacterial diseases is hampered by
considerable specificity, even among those most generally pathogenic. The
host range varies from a single host species to a few usually fairly closely
related species or genera, which is a narrow spectrum of activity when
compared with most modern insecticides. However, most crops are attacked
by a wide range of insects belonging to several orders, which vary from
almost complete susceptibility to no susceptibility to a particular organism.
Hence, it seemed desirable to compare combinations of pathogenic agents
and insecticides with these two control methods used alone. It appears
that such an approach may be needed to interest growers in some areas
in microbial agents as a practicable component in the insect control
arsenal. Steinhaus (1957) discussed the harmlessness of these pathogens
to man and more recently (1959) discussed the improbability of Bacillus
thuringiensis Berliner mutating to forms dangerous to vertebrates. Certain
similarities between this species and Bacillus anthracis Cohn had caused
some concern.
The object of this investigation was to compare pathogens, insecticides,
and pathogen-insecticide combinations for the control of lepidopterous larvae
attacking cruciferous crops, and particularly the cabbage looper, Tricho-
plusia ni (Hbn.). Various workers in different parts of the United States
have discussed the difficulty of controlling this species in recent years,
Genung (1955), Hall (1957), McEwen and Hervey (1958), and McEwen
and Hervey (1958, 1959) showed that a polyhedrosis virus had possibilities
for control of the cabbage looper. Tanada (1956) and Hall and Dunn
(1958) reported that cabbage looper is not as susceptible to Bacillus thurin-
giensis, Berliner as are a number of other larvae, and that a relatively high
spore concentration is required to give a reasonable degree of control.

1Florida Agricultural Experiment Station Journal Series, No. 1050.
2Mr. C. E. Seller, Field Assistant was helpful in various aspects of
the work. Mr. Edward King, Jr., Draftsman, and Mr. H. P. Ruffolo, Staff
Assistant, prepared the graphs.
3Associate Entomologist Everglades Experiment Station, Belle Glade,

66 The Florida Entomologist Vol. 43, No. 2


Collards, Brassica oleracea var. acephalica L., was selected as the test
crop since it supports large populations of loopers and other caterpillars.
Only the cabbage looper occurred in this experiment except for a trace
population of imported cabbage worm, Pieris rapae (L.). A randomized
complete block design experiment was employed and treatments were repli-
cated five times. The plots were four rows wide (36 inches between rows)
and 25 feet long. There was a 12-foot buffer zone between plots and
blocks. Emulsifiable concentrates of 4 insecticides were used. The amounts
per acre of each material when used alone was as follows: Toxaphene
2.00 lbs., Phosdrin 0.25 lbs., Guthion 0.375 lbs., Dimethoate 0.50 lbs. The
source of the native polyhedrosis virus studied was from looper cadavers
collected the previous summer and stored at room temperature in a pint
jar. When the test was started the liquified loopers were measured in
milliliters and an equal amount of distilled water added to form a stock
solution. This material was used at a rate of 60 milliliters or 1.6 x 10 8
polyhedra per 100 gallons of spray per acre. A standard chemical insecti-
cide for looper control (toxaphene) was used in combinations with both
the virus and with the Bacillus. Both the insecticide and the pathogenic
agents in the combinations were used at one-half the dosage when used
alone. Triton B-1956 spreader-sticker was added to all the spray mixtures.
A formaldehyde solution was used to disinfect equipment to avoid possible
accidental contamination of plots. Materials were applied with a self-
propelled spray rig [Harrison et al (In press)] at a rate of 100 gallons
per acre and 250 p.s.i.
An application was made when the plants were about 18 inches tall.
However, plants were overlapping in the row middles, so that good cover-
age was difficult.
Evaluation of looper control was made by a count of surviving loopers
on 10 leaves per plot at 5 and 7 days after application. Data collected
at 14 days consisted of larval injury to the foliage. The number of holes
exceeding 1/16 inch in diameter per ten-leaf sample was recorded. The
last count was based on damage because more than a week of hot, humid
weather with heavy rainfall had resulted in considerable reduction of
loopers through natural appearance of the polyhedrosis epizootic. Genung
(1951) has discussed the rapidity of movement of this natural infection
under Everglades conditions.

The results of this experiment are shown graphically in Figure 1.
Five day count: All treatments were significantly better than phos-
drin. The toxaphene-polyhedrosis virus combination and Bacillus-toxaphene
combination gave the lowest count of surviving larvae but these treatments
were not significantly better than either toxaphene or the Bacillus used
alone. Apparently the polyhedrosis virus used alone had attained only
partial effectiveness 5 days after application as it resulted in a higher
number of surviving loopers than all treatments except phosdrin. Un-
recorded observations made at 48 hours after treatment indicated that
Dimethoate, Phosdrin and Guthion gave adequate initial knockdown but

Genung: Comparison of Insecticides

did not have enough residual activity against the large population in the

SToxophene+ Polyhedrosis virus Toxaphene + Polyhedrosis virus

LS virus
Toxophene 5% Level Toxaphene
5 days I LSD
Bacillus ihuringiensis7 d Polyhedrosis virus 5% vel

Bacillus thuringiensis + Toxaphene Toxaphne + Bacillus thuringiensis

S Polyhedrosis virus Dimethoate

SDimethoate Guthion

Guthion Bacillus thuringiensis

Phosdrin Phosdrin

0 5 ;0 15 20 25 30 45 50 55 0 100 200 300 400 500 800 900
Average number of Loopers Average number of worm holes
Figure 1. Comparative effective- Figure 2. Comparative effective-
ness of the insecticides, pathogens, ness of the treatments at 14 days
and insecticide-pathogen combina- from application, based on amount
tions at 5 and 7 days after applica- of leaf injury.
tion, based on larval count.

Seven day count: Although the population continued to rise in the
checks and in the phosphatic treatments the number of loopers declined
in the polyhedrosis-toxaphene combination, toxaphene, polyhedrosis, and
Bacillus treatments. The toxaphene-polyhedrosis virus combination gave a
lower count in all replicates but was not significantly better than toxaphene,
polyhedrosis virus, or the Bacillus. However, it was significantly better
than the Bacillus-toxaphene combination.
Fourteen day count: Since the data for this count were based on injury
and therefore cumulative, perhaps it is not exactly comparable with the
two previous (larval) counts. However, it parallels and quite closely
compliments the two larval counts. The data showed the polyhedrosis-
toxaphene combination to be significantly better than all other treatments.
Toxaphene, polyhedrosis virus, and the Bacillus-toxaphene combination
approached the effectiveness of the virus-toxaphene combination. The
Bacillus used alone apparently had shown its maximum effect and began
declining sometime between the 7- and 14-day counts. For looper control
it would possibly need to be applied with the regularity of a chemical
insecticide. On the other hand the polyhedrosis virus maintained itself
longer, indicating that a localized epizzotic was initiated. As might be
anticipated, the data indicated that there was a direct relationship between
interval from application and effectiveness of the phosphatics (Figure 2).

68 The Florida Entomologist Vol. 43, No. 2

Although organisms and insecticides in combination were used at only
half the amounts of each material when used singly, it was indicated that
a control program might be considerably improved by such combinations.
However, other insecticides might not indicate the degree of compatibility
shown by toxaphene when combined with these organisms and a need for
such testing is indicated. The polyhedrosis virus-toxaphene combination
was particularly outstanding and gave a consistently lower count than
either component at double the dosage. When used alone the organisms
compared favorably with the chemicals in normal use.
For best results, good coverage with insect pathogens is probably almost
as essential as with a chemical insecticide. Had it not been for the extreme
density of the foliage in these plots better control with all treatments might
have been obtained.
If it can be assumed that an individual not killed by an insecticide would
become infected, then it would appear that the combined use of insecticides
and pathogens would tend to slow the development of resistance to in-
Genung, W. G. 1951. Fla. Agr. Expt. Sta. Annual Report for 1951: 183.
Genung, W. G. 1955. Fla. Agr. Expt. Sta. Annual Report for 1955: 241.
Hall, Irvin M. 1957. Use of a polyhedrosis disease to control cabbage
looper on lettuce in California. Jour. Econ. Ent. 50 (5): 551-553.
Harrison, D. S., W. G. Genung, and E. D. Harris. 1959. A small self-
propelled sprayer for agricultural research. Fla. Ent. 42 (4) :169.
Hall, Irvin M., and P. H. Dunn. 1958. Susceptibility of some insects to
infection by Bacillus thuringiensis Berliner in laboratory tests.
Jour. Econ. Ent. 51 (3): 296-298.
Hervey, G. E. R., and K. G. Swenson. 1954. Effectiveness of DDT for
cabbage looper control in western New York 1944 and 1953. Jour.
Econ. Ent. 47 (4) : 564-567.
McEwen, F. L., and G. E. R. Hervey. 1958. Control of cabbage looper
with a virus disease. Jour. Econ. Ent. 51 (5): 626-631.
McEwen, F. L., and G. E. R. Hervey. 1959. Microbial control of two
cabbage insects. Jour. Insect Path. 1: 86-94.
Rabb, Robert L., Edward A. Steinhaus, and Frank Guthrie. 1957. Pre-
liminary tests using Bacillus thuringiensis Berliner against horn-
worms. Jour. Econ. Ent. 50 (3) : 259-262.
Steinhaus, Edward A. 1957. On the harmlessness of insect pathogens.
Jour. Econ. Ent. 50 (6) : 715-720.
Steinhaus, Edward A. 1959. On the improbability of Bacillus thurin-
giensis Berliner mutating to forms pathogenic for vertebrates. Jour.
Econ. Ent. 52 (3) : 506-508.
Tanada, Yoshinori. 1956. Microbial control of some lepidopterous pests
of crucifers. Jour. Econ. Ent. 49 (3): 320-329.


Central Florida Experiment Station

Since resistance of the house fly to DDT was reported in 1947, addi-
tional reports of resistance of other insects continue to appear in the
literature. At present insects attacking vegetable crops reported to be
developing resistance to insecticides include the imported cabbage worm
(McEwen and Chapman, 1952), the cabbage looper (Reid and Cuthbert,
1957), the southern wireworm (Reid and Cuthbert, 1956), and the serpen-
tine leaf miner (Wolfenbarger, 1958). The increased interest during
recent years in this subject of resistance has stimulated the compilation
of the data presented in this paper. These data represent results from
the use of DDT dust and 25 percent DDT emulsifiable formulations taken
from experiments which included other insecticides. The experiments were
conducted each spring from 1949 through 1959 at the Central Florida Ex-
periment Station at Sanford, Florida.

The cultural practices recommended for central Florida were followed.
These included land preparation and soil fumigation for nematode control,
a between-the-row spacing of 30 inches and an in-the-row spacing of 12
inches with a single plant in each hill, and 3000 pounds per acre of 5-5-8
or equivalent fertilizer, with 500 pounds per acre applied in the row prior
to seeding and the remainder in three equal applications as side dressing
at fourteen day intervals. Usually an additional side dressing was applied
at tassel appearance consisting of 200 to 300 pounds per acre of nitrate
of soda. Shallow cultivation for weed control was practiced at irregular
intervals as required.
The plots treated with emulsifiable formulations were 4 rows wide in
1949 as was the case for both dust and liquid formulations in all of the
other years. The plots were 60 feet long, with 15-foot alleyways between
blocks. There were 4 replicates with the treatments arranged in a simple
random pattern in each block. In most years different plantings made
on the same date of the same sweet corn variety were used for the dust
and emulsifiable formulations. For this reason the data for the two types
of formulations are not statistically comparable.
In 1949 the plots treated with dust formulations were 6 rows wide to
accommodate a six-row power duster. Because of the difficulty of cleaning
this machine between treatments, rotary type hand dusters were used all
other years. The discharge outlet of both the machine and hand dusters
were held slightly above the silks of the upper ears and the duster passed
down one side of each row at each application. An attempt was made to
apply the dusts at the rate of 30 pounds per acre, but in actual practice

'Florida Agricultural Experiment Station Journal Series, No. 1006.

The Florida Entomologist



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Wilson: DDT for Corn Earworm Control 71

the amount applied varied from 20 to 50 pounds per acre. The figures given
in Table 1 were obtained by weighing the duster before and after each
application and are averages for the year.
The same power sprayer was used during the entire period. It was
equipped with a four-row boom having 2 nozzles on each side of the row,
arranged in such a manner that one nozzle was directed at the silks of the
upper ear and the other nozzle at the lower ear. At the beginning of each
corn spray season new disks having an orifice of 0.041 inch were placed
in the spray nozzles and the amount of liquid being applied per acre was
determined (Table 1).
A laboratory mixed preparation was used for the 1949-1952 experiments
with dust formulations. A 50 percent wettable powder was used as the
source of DDT and Pyrax was used as the diluent. The dust was mixed
in a Day Laboratory Mixing Machine. For 1953 to 1959 inclusive com-
mercially prepared dust mixtures were used while in 1951 and 1952 a
laboratory prepared emulsifiable concentrate was used. The concentrate
was prepared using the following formula (all proportions are by weight);
25 percent DDT (setting point 89 C.), 72 percent Xylene and 3 percent
Triton X155. For the other years commercially prepared 25 percent emulsi-
fiable DDT was used as the source of DDT for the spray treatments.
In all years applications of the insecticides were started the day after
the first silks were observed. The interval between applications varied
from year to year. These intervals are given in Table 3. In most cases
approximately 10 per cent of the ears were estimated to be in silk by the
second day of silking. Beginning in 1954 and each year thereafter daily
counts were made of the percent of upper ears in silk, until 100 percent
of these ears were in silk. A summary of these data is presented in Table 2.
The dust formulations were applied beginning about 6:00 A.M. to take
advantage of the relatively calm portion of the day. The spray formula-
tions were usually applied between 8:00 A.M. and noon.
Table 2 also gives the number of days rainfall occurred and the total
amount in inches of rainfall during the spray period. Sometimes rain
fell shortly after the insecticides had been applied. When this occurred
the applications were made again the next day. When the rain occurred
during the day following the scheduled application, the insecticides were
applied the next scheduled day for application of the insecticides.
At harvest time all of the upper ears of the two center rows of each
plot were harvested and weighed in the husk. The recorded weights of
the unhusked ears are not included as a part of the presented data, because
differences in weights of corn from the treated and untreated plots were
not statistically significant. This was interpreted to mean that the in-
secticides did not adversely affect the yields of corn.
After the weights were recorded, 50 ears from each plot were husked
and examined for earworm injury. These ears were divided into two classes,
uninjured and injured. The degree of injury was not considered in the
evaluation of the insecticides. From these records the percent of worm-free
ears was calculated. These percentages were the basis upon which the
insecticides were evaluated.

The Florida Entomologist


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Wilson: DDT for Corn Earworm Control 73

A description of some of the factors affecting the growth of the corn
plant has been given in some detail in the preceding section. Such factors
as land preparation, nematode populations, fertilization, cultural practices,
and weather conditions throughout the growing period affect the uniformity
of stand and growth rate. Harris (1958) has presented data showing that
the degree of earworm damage in varietal trials is affected by the uni-
formity of the stand. The rate of growth in turn affects the time required
for all of the ears to produce silks. Soil and atmospheric moisture and
atmospheric temperatures affect the duration of the period the silks are
attractive to ovipositing earworm moths. Thus, every effort should be
made to grow the corn uniformly and rapidly to reduce the length of time
the ears are exposed to earworm attack.
Results are recorded in Table 3. A very high degree of control was
obtained in 1949 with both the 5 and 10 percent dust formulations applied
to the corn harvested April 18. Poor control was obtained with the 5
percent DDT dust in all cases where it was used, except in the early plant-
ing of 1949 when a very low earworm population was present and in 1953
in the presence of a high earworm population (1 percent worm-free ears
from the untreated plot). Sweet corn growers were using 10 percent DDT
dust in 1949. At the present time almost all of the growers use a 10
percent DDT dust or dust combinations of DDT with parathion or chlor-
dane. This is readily understood when the data in Table 3 are examined.
All of the Florida sweet corn is produced for the fresh market which
requires a U. S. Fancy grade (no wormy ears allowed). Attention should
also be directed to the fact that higher degrees of control are obtained in
commercial fields than appears to be possible in small experimental plots.
The degree of control obtained with both the dust and emulsifiable
formulations in 1957 and 1958 is lower than that obtained in other years.
The control obtained by both formulations is somewhat erratic when the
entire eleven-year period is considered. The reasons for these variable
results are not clear at this time.

Data obtained over an eleven-year period on some of the factors affect-
ing earworm control and results from applications of DDT dust and
emulsifiable formulations are presented. These data indicate that, if
dust formulations are to be used, a 10 percent DDT dust is required to
give a satisfactory control. In 1951, good control was obtained with 3
quarts of 25 percent emulsifiable DDT plus mineral oil in an early planting
and poor control in a later planting. In 1953, 1955, and 1959, 4 quarts
of 25 percent emulsifiable DDT plus mineral oil produced good results.
In 1956 and 1959, 5 quarts of 25 percent emulsifiable DDT gave a good
control while the same treatment was considerably poorer in 1954, 1957,
and 1958. These data indicate that the control with both formulations
was erratic. Although poor control was obtained with both the dust and
emulsifiable formulations in 1957 and 1958, the data do not indicate that
the corn earworm is developing resistance to DDT.

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Wilson: DDT for Corn Earworm Control

Harris, Emmett D., Jr. 1958. Factors affecting the results of corn ear-
worm control studies. Fla. Ent. 41:2: 51-60.
McEwen, F. L., and R. Keith Chapman. 1952. Imported cabbage worm
resistance to insecticides. Jour. Econ. Ent. 45:4: 717-722.
Missiroli, A. 1947. Riduzione O eradicagione degli anofeli. Riv. di Paras-
sitol. 8: 141-169.
Reid, W. J., Jr., and F. P. Cuthbert. 1956. Resistance of the Southern
potato wireworm to insecticides. Jour. Econ. Ent. 49:6: 879-880.
Reid, W. J., Jr., and F. P. Cuthbert. 1957. Control of caterpillars on com-
mercial cabbage and other cole crops in the South. U. S. D. A.
Farmers Bul. 2099.
Wolfenbarger, D. 0. 1958. Serpentine leaf miner: brief history and sum-
mary of a decade of control measures in South Florida. Jour. Econ.
Ent. 51:3: 357-359.


Foaori*s and Ofices: TAMPA and FORT PIERCE, FLORIDA

A Cyanamid Report:

What's new with Malathion?

New intervals for Malathion- Malathion continues to be the ideal
material for late season insect control. Reduced intervals between last
application and harvest were received on these crops in 1958:
Tomatoes from 3 days to 1 day with malathion 57% Emulsifi-
able Liquid, malathion 25% Wettable Powder and
malathion 4% to 5% dusts.
Pears from 3 days to 1 day with malathion 57% Emulsifi-
able Liquid.
Squash >- from 3 days to 1 day with malathion 57% Emulsi-
Melons f fiable Liquid, malathion 25% Wettable Powder and
4% to 5% dusts.
Brambleberry Family from 7 days to 1 day with malathion 57%
Emulsifiable Liquid, malathion 25% Wettable Pow-
der and 4% to 5% dusts.
Extended interval: The label for leaf lettuce has been extended from
10 days to 14 days. The label for head lettuce remains the same: 7 days.
New crop uses for Malathion Label acceptance of malathion for
insect control on figs and okra extends its already long crop use list to 95.
Okra For the control of aphids. Use recommended rates of
malathion Emulsifiable Liquid, Wettable Powder or dusts
up to time pods start to form.
Figs For control of dried fruit beetles and vinegar flies. Use
Emulsifiable Liquid or dusts at recommended rates. Apply
when necessary up to 3 days from harvest.
New animal claims In addition to label acceptance for direct appli-
cation on cattle, hogs, poultry, cats and dogs, malathion has received
these labels for direct application on sheep, goats and swine:
For the control of lice, ticks and keds on sheep and goats. Apply 16 lbs.
of malathion 25% Wettable Powder per 100 gallons of water. Spray
animals thoroughly. Repeat application after 2 or 3 weeks if needed.
Do not apply to milk goats. Do not treat animals under one month of
age. When applying sprays, avoid contamination of feed, food contain-
ers and watering troughs.
For the control of lice on swine, use malathion 4% or 5% dust making
a thorough application to the animals. In addition, pens should also be
thoroughly dusted. Repeat application in 10 days, and thereafter as
needed. Avoid contamination of feed, food containers and watering

Developer and producers of
malathion and parathion. crava nAr z

American Cyanamid Company, M AU A Ef
Agricultural Division, Dept. HE, MALAT H IN



The development of new types of lamps in the last few years has re-
newed interest in the use of light traps for insect surveys. Glick and
Hollingsworth (1954, 1955, 1956) showed that lights emitting energy in
the near ultraviolet and visible regions of the electro-magnetic spectrum
were attractive to adults of the pink bollworm (Pectinophora gossypiella
[Saund.]), and that such lights were valuable for insect surveys. Merkl
and Pfrimmer (1955) found that other cotton pests were also attracted to
ultraviolet light.
Ultraviolet, or black, light traps have been used principally for surveys
of lepidopterous pests; thus there have been few references indicating that
such lights were attractive to Diptera. Pfrimmer (1955) recorded rather
large numbers of Diptera taken during the early months of the year, but
he did not list family response within the order. In studies with different
types of ultraviolet lamps and trap designs, Frost (1957) listed eight
families of Diptera as well as "midges" and "miscellaneous Diptera," but
made no mention of the Tabanidae. Tabanids have been reported from New
Jersey light-trap collections. MacCreary (1940) reported 10 species from
this type of trap in Delaware, and Frost (1953) recorded 19 species in
Pennsylvania. Apparently the first indication that tabanids were attracted
to ultraviolet was that given by Hetrick (1955), who reported 25 families
of Diptera from collections in Florida.
The collections recorded here were made by L. A. Hetrick at his resi-
dence in Gainesville, Florida. The commercially built omnidirectional trap
is similar in design to the Pennsylvania No. 1 trap described by Frost
(1957). The light source was a 15-watt GEBL fluorescent lamp that
radiated energy in the near ultraviolet region (2,800-3,800 angstroms).
The lamp was mounted vertically between four baffles. The light and
baffle unit was constructed over an 18-inch funnel that tapered to 3 inches
at the lower end and was fitted with a plastic cup. It was supported on
a metal tripod.
The trap was operated primarily for the accumulation of teaching ma-
terial at the University of Florida. The operation hours were from about
15 to 30 minutes before dark until 10 to 10:30 p.m., depending upon early
evening temperatures and other weather conditions. As the collections
were usually stored for several months before use, all the specimens were
killed and preserved in 70-percent isopropanol. At first it was believed
that wet preservation would interfere with their identification; however,
most of the flies were easily pinned and when dry they could hardly be
differentiated from dry-killed pinned specimens.
The first group of tabanids examined was an accumulation of specimens
separated from trap collections made during the summer months from

1 The research for this paper was done while the author was attending
the University of Florida.
SEntomology Research Division, ARS, U.S.D.A.

78 The Florida Entomologist Vol. 43, No. 2

1954 through 1958. The flies were removed from the preservatives, pinned,
and allowed to dry 24-48 hours before determinations were attempted. A
list of the species 3 and the sexes represented is given below.

Chlorotabanus crepuscularis (Bequaert) ....----............--- ..... 9
Diachlorus ferrugatus (Fabricius) --....--------.........--..----..........
Leucotabanus annulatus (Say) ....--............-...................... -
Tabanus, aar Philip ..................-...................-..--.......-- 9
americanus Forster ...------ --................. ...-...--........... S 9
atratus Fabricius -----------................... ...............
gladiator Stone -- --- --.........----.............................- 9
gracilis W iedemann .....--......-- ----------.........- ...... ...-. 9
imitans W alker --...--- --............. .... .............-.......
imitans excessus Stone ......... ------------............ ... ...... .. 9
johnsoni H ine ..................................... .... ............. 9
lineola Fabricius ..................--.... -..........-..-............
melanocerus Wiedemann ...............-.. ..........-....-...-..- 9
nigripes Wiedemann ---...........----......---- ........-- ...... 9
pumilus Macquart ......-.........--........---...--.......-...------
stygius Say ......---..... ---...................................... 9
sulcifrons M acquart ..................--------.. ....-- ..... .......
zythicolor Philip .............- ................................ $---- 9

Chrysops flavidus [i.e. flavidus] Wiedemann ..----.......... .. 9
flavidus reicherti Fairchild ..........................-.............. 9
montanus perplexus Philip ........................................... $

The second group consisted of the specimens attracted to the ultra-
violet-light trap between April 23 and July 31, 1959.


Chlorotabanus crepuscularis .................... -................-... 12 9
Diachlorus ferrugatus ..................................-..-.........-.......... 0 2
Tabanus aar ......................... .... ................ ....... 0 3
americanus -- ------......................... -.................... 1 0
fumipennis Wiedemann -----.............-..-......-....-.. .. 2 0
gladiator -- ------..................... ...... .................... 1 2
gracilis ---.............. ........ ......--. .................... ..... 0 1
im itans ............................................................. 0 2
lin eola ................... ........ ... ........ .................. ....... 43 9
m elanocerus --------.......................- ..................... 1 1
nigripes ..................................---- -........- ................. 2 3
zythicolor ---------------................ -- .....-.....-...... 0 1

3Alan Stone, Entomology Research Division, U.S.D.A., assisted in the
identification of some specimens.

Anthony: An Ultraviolet Light Trap


Chrysops flavidus ..--.......... .-----~.........-...... ....- 0 2
vittatus floridanus Johnson ----...----------------- 0 1

Total -----... .. ...- ... --...........- ----.. 62 36

Tabanus lineola was the predominant species in both these collections,
the males outnumbering the females by nearly 5 to 1 in the latter group.
Chlorotabanus crepuscularis was next in abundance in 1959, but this species
was represented by only a single specimen from 1954 through 1958. Of
the 14 species and subspecies and 98 specimens collected in 1959, only 37
percent were females. This figure is obviously influenced by the high ratio
of lineola males. As the males of some species are difficult to collect, it
may be significant that of the total of 23 species and subspecies taken from
the trap, males of 14 species were present. In 1959 the individual species
appeared in the traps at about the same time as the expected period of
adult activity.
The number of tabanids attracted to the trap was small, probably no
more than 0.001 percent of the total insect catch. In the period 1954
through 1958, only 133 specimens were taken but they were separated from
the collections by students and it is possible that many specimens were
overlooked or purposely discarded. This assumption is further supported
by the collection of 98 horse flies and deer flies from the trap between
April 23 and July 31, 1959. It is believed that only a small percentage of
the tabanids attracted to the light become trapped in the plastic cup.
Some of the specimens reported here were taken from the baffles, fluorescent
tube, or the funnel of the trap. The yield of tabanids could probably be
considerably increased by careful observation of the trap during operation.


Twenty-three species and subspecies of tabanids divided among five
genera and two subfamilies were recorded from two groups of ultraviolet-
light trap collections in Gainesville, Florida, one in 1954 through 1958 and
the other in 1959. Males of 14 species and subspecies were present in the
collections. Tabanus lineola was the predominant species, followed by
Chlorotabanus crepuscularis. In the 1959 collections, the males of lineola
outnumbered the females by nearly 5 to 1. Of a total of 98 specimens at-
tracted to the ultraviolet light trap during 1959, only 37 percent were
Frost, S. W. 1953. Tabanidae attracted to light. Ann. Ent. Soc. Amer.
46(1) : 124-125.
Frost, S. W. 1957. The Pennsylvania insect light trap. Jour. Econ. Ent.
50(3) : 287-292.
Glick, P. A., and J. P. Hollingsworth. 1954. Response of the pink boll-
worm moth to certain ultra-violet and visible radiation. Jour. Econ.
Ent. 47(1) : 81-86.

The Florida Entomologist

Glick, P. A., and J. P. Hollingsworth. 1955. Response of moths and other
cotton insects to certain ultra-violet and visible radiation. Jour.
Econ. Ent. 48(2) : 173-177.
Glick, P. A., and J. P. Hollingsworth. 1956. Further studies on the at-
traction of pink bollworm moths to ultra-violet and visible radiation.
Jour. Econ. Ent. 49(2) : 158-161.
Hetrick, L. A. 1955. The use of ultra-violet light for obtaining insect
specimens for use in teaching. Entomological Society of America.
MacCreary, D. 1940. Report on the Tabanidae of Delaware. Delaware
Agr. Expt. Sta. Bull. 226, 41 pp.
Merkl, M. E., and T. R. Pfrimmer. 1955. Light trap investigations at
Stoneville, Mississippi, and Tallulah, Louisiana, during 1954. Jour.
Econ. Ent. 48(6) : 740-741.
Pfrimmer, Theodore R. 1955. Response of insects to three sources of
black light. Jour. Econ. Ent. 48(5): 619.

P. O. Box 7067


Complete Line of Insecticides, Fungicides and
Weed Killers

California Spray-Chemical Corp.
Located at Fairvilla on Route 441 North

ill -Ilr,-- I

Vol. 43, No. 2


Phone 3-0506



Anchylopera platanana Clemens, a well-known planetree feeder, was
found eating the leaves of planetrees by the writer in the Gainesville area
in the summer of 1958. This was the first report of this insect in Florida
in the State Plant Board records.
Clemens (1860) first described the insect and gave the type locality as
Pennsylvania and the host plant as planetree. He indicated two possible
generations a year in Pennsylvania. This insect was later described by
Zeller (1875) as Phoxopteris marcidana, by Walsingham (1884) as Phoxop-
teris platanana and by Fernald (1903) as Ancylis platanana. Other distribu-
tion records given by Mackay (1959) are Arkansas, District of Columbia,
Illinois, Maryland, Missouri, New Jersey, New York, Ohio, Virginia, West
Virginia and Grand Bend, Ontario, Canada. She illustrates the larval
stage and gives the width of the head capsule of the last instar of two
larvae as 0.66 mm. and 0.88 mm. A life history study and some observa-
tions on the biology of A. platanana were made in the Gainesville area
during the summer and fall, 1958, and the spring, summer and fall, 1959.

As far as is known this insect is host specific to planetree. The plane-
trees on the campus of the University of Florida, probably the largest
planting in Alachua County, were almost all heavily infested in the summer
and early fall of 1958. There were local heavy infestations with light
general infestations in the Gainesville area in 1959.
After the initial find of A. platanana in June, 1958, weekly observations
were made in the vicinity of Gainesville. By July it was evident that this
was a multibrood insect with overlapping generations. Although most of
the planetrees had shed their leaves by November 1, adults were present
and attracted to light in the evenings. No adults were observed at light
after November 16, 1958, and in 1959 no adults were seen at planetrees
or at lights after October 14, although almost half of the leaves remained
on some of the trees. The prepupa, the overwintering stage, could be
found in fallen leaves both years.

SContribution No. 4, Entomology Department, State Plant Board of
Florida, Gainesville, Fla.
2 This report was part of a graduate problem course in the Department
of Entomology, University of Florida, 1958 and 1959.
SChief Entomologist, State Plant Board of Florida, Gainesville.
S"Sycamore is the forestry name for this genus and is also, unfortun-
ately, strongly entrenched in American usage. Sycamore (meaning 'Fig
Mulberry' or rather 'Mulberry Fig') is a patent misnomer for the genus
Platanus, and has arisen from a similarity in leaf shape to the 'Sycamore'
of the Bible." Harlan P. Kelsey and William A. Dayton. 1942. Standard-
ized Plant Names Second Edition. J. Horace McFarland Co., Harrisburg,
Pa., p. 612.

The Florida Entomologist

Two adults (1 ,1 9) were flushed from the grass beneath a planetree
on the University of Florida campus on March 13, 1959. The female was
examined and eggs were found in which embryos were beginning to de-
velop. A second female was caught on the side of a building in Gainesville
after a rain in the afternoon of March 19.
Buds on planetrees began opening March 18 in the Ocala area and
March 25 in the Gainesville area. Planetrees on the campus of the Uni-
versity of Florida were checked twice a week for A. platanana following
the formation of leaves April 1. The first infestation with first and second
instar larvae was found on April 13 near the sewage disposal plant on the
campus of the University. A second infestation was found April 25, and a
third infestation was found May 2, both in the Gainesville area. The three
infestations were in areas where some of last year's leaves could still be
found. This was especially true of the area around the sewage disposal
unit. Pipes were stacked near a twenty-five foot planetree and afforded
numerous places for fallen leaves to lodge. Hedges in the other areas of
infestation prevented all fallen leaves from being raked clean and destroyed.

Leaves infested with larvae were gathered and placed in containers in
an insectary for adult and parasite emergence.
For egg deposition, recently emerged adults were kept in small wire
cages 1 foot wide, 1 foot high and 2 feet long. One female adult was placed
in one cage; 6 adults, 3 females and 3 males were placed in a second cage;
12 adults, 6 females and 6 males were placed in a third cage and 24 adults,
12 females and 12 males were placed in a fourth cage. All tests were
replicated 3 times. All cages contained 8 4-dram vials with 2 leaves in-
serted in each vial for egg deposition. A vial of water plugged with cotton
was placed in each cage for adult moths.
Two methods for keeping the leaves turgid were tried. A half-inch
galvanized pipe with 3 six-inch uprights 12 inches apart connected by one-
half inch rubber tubing to a gallon jug of water was tried first. Half-inch
rubber stoppers with a one-eighth inch hole in each stopper were fitted into
the ends of the uprights with the plant part inserted into the hole in each
stopper. Modeling clay was packed around the stem at the bottom end of
each stopper to prevent any water leakage. A second method was tried
and later used for all tests by placing 2 leaves with short stems in a
4-dram vial. A notch was cut in the side of the cork to accommodate the
stem, and the cork was inserted into a vial filled with water. A plastic,
opaque bag was placed over the plant parts, gathered around the vial
and secured with a rubber band. As the adults emerged in these plastic
bags, they were transferred to screened cages.
Two cages, 1 containing 12 and a second containing 24 adults, were
placed in a temperature controlled room (74-80 F.). All tests were repli-
cated 3 times. To obtain the average width of the head capsule, measure-
ments were taken from 100 larvae in each instar. For peak emergence
in the field, adults were counted on 10 leaves selected at random on 4 sides
of a tree. Three sites were selected for these counts. Temperatures for
field conditions were taken from the United States Weather Bureau Clima-
tological Data Station, located at Gainesville.

Vol. 43, No. 2

Denmark: The Biology of Anchylopera platanana 83

Figure 1. Egg of Anchylopera platanana Clemens.

9 mm
Figure 2. Larva of Anchylopera platanana.

The Florida Entomologist


Eggs (Figure 1) resembling small, gelatinous droplets, round to oval
in shape, almost colorless and approximately 0.09 mm. in size were laid
on the leaves.
The last instar, pale yellow larvae (Figure 2) average 9-11 mm. in length.
The average widths of head capsules of 100 larvae in the first, second, third
and fourth instars are 0.20 mm., 0.33 mm., 0.60 mm. and 0.83 mm., re-
The larvae begin feeding at the base of the leaf on either side of the
midrib. If more than 2 larvae are on one leaf, additional larvae begin
their feeding farther up the leaf, usually where a vein branches.
The larvae spin fine, silken webs over the feeding area. The felty
tomentum growing on the leaf, excrement and any other materials found
on the surface of the leaf are removed and pushed under the edge or
through the webbing before the larvae commence feeding. The larva
attaches itself in an upside down position to the webbing, lowers its head
to the surface of the leaf and begins to feed. The web is extended as more
area is needed. The larva skeletonizes the leaf and forms a tuck along the
skeletonized area by attaching a web to a vein on one side and to the leaf
surface beyond the feeding area on the opposite side and draws the leaf
The pupa (Figure 3) is light yellow and averages about five millimeters
in length. The larvae usually pupate within the folded area of the leaf,
however, a larva may leave the folded area, spin a web on the adjacent
surface of the leaf, and pupate beneath the web.
The adults have a wing spread of approximately 13 mm. The fore-
wings are pale reddish with white markings along the costa and the base
while the extreme apex is dark reddish. The hind wing, head, thorax and
abdomen are whitish.
Under laboratory conditions, with a temperature range of 74-80 F.
and relative humidity approximately 74 per cent, the average time required


Time in Number of Days

Stage of Development Minimum Maximum Average

Egg .--...---...-.. .... --.. ..... -. .------- 3 5 4
First instar larva ...........----... ---... -.------- 2 3 2.5
Second instar larva .....--...... ---------------..... .---... 4 6 5
Third instar larva .---....----.......------ .. ---------.....-- 6 8 7
Fourth instar larva ...... ...........----------....... 7 9 8
Pupa to adult ~.~.--............. 9 11 10
Gestation .................... .-------.....------ 5 6 5.5

Totals .-....................-.....-....... 36 48 42

Vol. 43, No. 2

Denmark: The Biology of Anchylopera platanana 85

Figure 3. Pupa of Anchylopera platanana.

Figure 4. Adults of Anchylopera platanana.

The Florida Entomologist

to complete the life cycle was 42 days (Table 1). Under insectary con-
ditions, the average time to complete a life cycle was 451/2 days (Table 2).

TABLE 2.-LIFE CYCLE OF Anchylopera platanana CLEMENS

Time in Number of Days

Stage of Development Minimum Maximum Average

Egg ..-.........------------- ...-- ..-.. 3 5 4
First instar larva .....--.--.......... .. . ....-- 2 4 3
Second instar larva .....................-.....--... 5 6 5.5
Third instar larva ........... ... ............ 7 8 7.5
Fourth instar larva -................... ....... 8 9 8.5
Pupa to adult ........--- .... ----.. ....- ...------- ...-- 10 11 10.5
Gestation ....... ...... ........... ............ 5 6 5.5

Totals ........................ ........... 40 49 45.5

No attempt was made to record the daily temperatures in the insectary
as the temperature usually varies with the field temperature; however,
periodic comparisons were made and the temperature in the insectary was
usually five degrees higher.

About 20 per cent of all the pupae collected in the fall of 1958 were
parasitized with a chalcid (Brachymeria sp.) Larvae of a chrysopid
(Chrysopa rufilabris Burmeister)6 were found feeding on the larvae of
A. platanana in the summer of 1958.
No parasites were found in the first two generations in the spring of
1959. Less than 5 per cent of the pupae were parasitized in the third
and fourth generations. The parasites were the same new species of chalcid,
Brachymeria sp., and an eupelmid (Eupelmus sp.), C. rufilabris was pres-
ent in large numbers in April, May and June. Twenty-two per cent of
all the infested leaves in the field contained dead A. platanana larvae in
the folded leaves. It is assumed that most of these larvae were killed by
the chrysopids, as no other predators were observed and the larvae did
not appear to be diseased. Undetermined species of spiders were found
occasionally feeding on the adults of A. platanana.

Single adult females in all cage tests failed to lay eggs and died after
6 to 7 days. In all other cages, eggs were deposited on the top surfaces
along the midrib or lateral veins of the leaves in the late afternoon or

SIdentified as a new species by B. D. Burks, U. S. National Museum,
Washington, D. C.
6 Identified by W. E. Bickley, Department of Entomology, University
of Maryland, College Park, Maryland.

Vol. 43, No. 2

Denmark: The Biology of Anchylopera platanana

early evening. Very few eggs were deposited on the undersides of the
leaves under laboratory conditions. In the field, eggs were usually laid
on the under surfaces of the leaves along the midrib or lateral veins.
Under caged conditions there were as many as 23 eggs laid on one leaf.
Most of these were laid on the upper surfaces.
The slightly higher temperatures in the insectary apparently made
little difference, as adults began emerging about the same time in both
places. Peak emergence of adults in the field occurred about May 12,
June 23, August 5 and September 18, 1959. These dates were selected as
close as possible to the middle of the 7- or 8-day period when the largest
number of adults were present in the field. There was some overlapping
of the different stages in the third and fourth generations. This was due
in part to the range of 5 to 6 days for egg laying.
The overwintering prepupal stage could be found in the folded areas
of fallen leaves in the fall of 1958 and 1959. Adults were never observed
to take food or water in the field or insectary, although water was supplied
in each cage.
Heavy infestations were more generally found scattered throughout the
Gainesville area in the summer of 1958, while only a few local heavy
infestations, with widespread light infestations, were found in the spring
and summer of 1959. One possible explanation for the larger popula-
tion in 1958 was that the parasites and predators probably did not
survive the below-normal temperatures in the fall of 1957 and the spring
of 1958 as well as did A. platanana. Only an occasional chrysopid larva
was found feeding on A. platanana in the summer of 1958, and approxi-
mately 20 per cent of the pupae were parasitized in the fall of 1958.
Chrysopid larvae were numerous following a mild fall and winter in
1958-59 and helped reduce the population of the first, second and third
generations. No parasites were found in the first and second generations,
and less than 5 per cent of the third and fourth generations were parasitized
in 1959. The over-all population of A. platanana had been reduced by
predators in the spring, and with the presence of a few parasites in the
late summer and fall it was difficult to find larvae and only an occasional
prepupa stage after October 1, 1959. Parasites and predators apparently
can keep this pest under control in Florida provided weather conditions
are favorable.
Clemens, Brackenridge. 1860. Contributions to American lepidopterology
No. 6. Proc. Acad. Nat. Sci. Phila. 2d ser. [v. 12]:349.
Fernald, C. H. 1903. (In Dyar, Harrison G., A list of North American
Lepidoptera and key to the literature of this order of insects.) U. S.
Nat. Mus. Bul. 52:468.
Mackay, Margaret Rae. 1959. Larvae of the North American Olethreu-
tidae (Lepidoptera). Canad. Ent. Supplement 10. 91:153.
Walsingham, Lord Thomas de Grey. 1884. North American Tortricidae.
Trans. Ent. Soc. Lond. Pt. 1 (April) :145.
Zeller, P. C. 1875. Beitrage zur Kenntniss der nordamericanishen Nacht-
salter, bersonders der Microlepidopteren. Verh. Zool. bot. Ges.
Wien 25:207-360.

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The white peach scale, Pseudaulacaspis pentagon (Targioni), was first
observed in Florida in 1889 on peach trees in the vicinity of Molino (Gos-
sard, 1902). Since that time P. pentagon has spread throughout the state
and is now known to attack more than 60 species of plants (Riddick, 1955).
The natural enemies of the white peach scale have been adequately
recorded in many areas of the world (Anonymous, 1944; Bennett, 1956;
Simmonds, 1958). However, except for an early report by Gossard (1902)
telling of the twice-stabbed lady beetle, Chilocorus stigma (Say), feeding
on white peach scale, published records of natural enemies of this scale
in Florida are lacking. The records of parasites and predators which
follow were gathered during the period May 1, 1959, to October 1, 1959,
primarily from Alachua County.

Careful examinations of white peach scale infestations were made in
8 separate field locations in Alachua County and all parasites and preda-
tors observed were collected. Small sections of scale-infested twigs and
branches were returned to the laboratory from the collection sites and
placed in emergence boxes. Twenty-three samples, each consisting of at
least 300 scales were gathered with a minimum of 2 samples coming from
each of the collection areas. In addition, to establish authentic parasite-
host relationships, parasitized scales from each collection area were placed
individually in 1-dram vials where they were kept until the adult parasites
emerged. Dissections of scales were also carried out under a microscope.
Through the cooperation of Mr. Harold Denmark, Chief Entomologist
with the State Plant Board of Florida, arrangements were made to have
plant material infested with P. pentagon sent to the author in Gainesville
by State Plant Board field inspectors working in various parts of Florida.
In this manner small quantities of white peach scale were obtained from
Baker, Jefferson, Lake, Orange, and Volusia Counties. Recoveries made
from this material have been recorded here; however, many additional
samples of P. pentagon would be required before an accurate estimate

1A portion of a thesis submitted as partial fulfillment for the degree
of Master of Science in Agriculture at the University of Florida, January,
2 Assistant Director of Agriculture, Bermuda.
SThe author is indebted to the following persons for advice and assist-
ance: Dr. John T. Creighton, Dr. L. A. Hetrick, Dr. T. J. Walker, Dr.
Milledge Murphey, Jr., and Professor A. S. Muller, all of whom are on
the faculty of the University of Florida. Acknowledgment is also made to
Dr. Paul W. Oman, Head of the Insect Identification and Parasite Research
Branch, U.S.D.A., and his staff, for determining parasites and predators

90 The Florida Entomologist Vol. 43, No. 2

could be made of the distribution and abundance of natural enemies of
this scale within these 5 counties.


Two species of primary hymenopterous parasites were reared from
field-collected samples of white peach scale. In addition, 2 hyperparasitic
species were recovered.
The most common and most effective parasite of the white peach scale
in Florida appears to be the eulophid Prospaltella berlesei (Howard). This
species is endoparasitic in nature and attacks second-instar scales, prin-
cipally females. The parasite was recovered from every area in the state
in which samples of P. pentagon were secured.
There was no attempt to make detailed counts to determine the percent-
age of scales attacked by P. berlesei on the various samples. Spot counts
indicated, however, that there can be a great variation in the degree of
parasitism, even within small areas. Despite local variations in effective-
ness, P. berlesei must be considered an important agent in the control of
the white peach scale in Florida.
The second of the primary parasites recovered from P. pentagon was
Aspidiotiphagus citrinus (Crawford). This species was far less common
than Prospaltella berlesei, being recorded from only 2 of the 8 collection
areas in Alachua County, and from a single area in Baker County. A.
citrinus attacks second-instar male and female scales and is an endoparasite.
It is surprising that A. citrinus was not recovered more commonly since
this species has been recorded attacking purple scale, Lepidosaphes beckii
(Newman), and Florida red scale, Chrysomphalus aonidum (Linnaeus)
(Muma, 1955), and is presumed to be distributed throughout the State of
Florida. Seasonal variations in population of this parasite might account
for the poor recovery record since all investigations were conducted during
the summer months.
The effectiveness of Prospaltella berlesei was reduced considerably by
the hyperparasite Thysanus flavopalliatus (Ashmead), which was commonly
found attacking pupae of the primary parasite within the mummified bodies
of P. pentagon (Fig. 1). T. flavopalliatus was recovered from every
collection area with the exception of Lake County. Small numbers of the
eulophid Ablerus clisiocampae (Ashmead), recorded as a hyperparasite
on Prospaltella aurantii (Howard) by Muma (1959), were also recovered
from white peach scale. The identity of the primary parasite through
which Ablerus clisiocampae was developing was not definitely established,
but in all probability it was Prospaltella berlesei.
Three species of coccinellids were found feeding on white peach scale.
Two of these species, the twice-stabbed lady beetle, Chilocorus stigma
(Say), and Lindorus lophanthae (Blaisdell) were common and very effec-
tive predators. The third species, Exochomus children Mulsant, was found
only occasionally and never in large numbers.
Further investigation would undoubtedly uncover additional coccinellids
predacious on P. pentgona in Florida since several of the species listed by
Merrill (1922) as occurring in Florida are known to attack white peach
scale in other geographical areas (Bennett and Hughes, 1959).

Hughes: Natural Enemies of the White Peach Scale

Fig. 1.-Dorsal view of fully
developed pupa of Thysanus flavo..
palliatus within a second-instar
female of the white peach scale,
Pseudaulacaspis pentagon. Thy-
sanus flavopalliatus is secondary
through Prospaltella berlesei.

In addition to the coccinellids, a species of thrips, a lepidopterous larva,
and a chrysopid larva were recorded in association with white peach scale.
The thrips, Haplothrips sp. nr. americanus (Hood), was quite common,
particularly when scale infestations were heavy. This thrips species is
apparently a scavenger rather than a predator.
Larvae of the cosmopterygid moth, Pyroderces rileyi (Walsingham),
were recovered regularly from white peach scale material. The larvae
tunnel among encrusted scales, living as scavengers.
Several larvae of an unidentified chrysopid were collected in association
with P. pentagon infestations in the Gainesville area. While the larvae
were apparently feeding on one or more stages of the scale, the number
of these predators was so small as to make them economically unimportant.

An investigation of the natural enemies of white peach scale, Pseudaula-
caspis pentagon (Targioni), was conducted in Alachua County, Florida,
during the summer of 1959. Two parasites, Prospaltella berlesei (Howard)
and Aspidiotiphagus citrinus (Crawford), along with the coccinellid preda-
tors Chilocorus stigma (Say), Lindorus lophanthae (Blaisdell), and Exo-
chomus children Mulsant, were recorded as attacking P. pentagon.
Thysanus flavopalliatus (Ashmead), a secondary parasite through P.
berlesei, was very common.

92 The Florida Entomologist Vol. 43, No. 2

Anonymous. 1944. A catalogue of the parasites and predators of insect
pests. Section 1, part 3. The Imperial Parasite Service, Belleville,
Bennett, F. D. 1956. Some parasites and predators of Pseudaulacaspis
pentagon (Targ.) in Trinidad, B.W.I. Can. Ent. 88:704-705.
Bennett, F. D., and I. W. Hughes. 1959. Biological control of insect pests
in Bermuda. Bull. Ent. Res. 50:423-436.
Gossard, H. A. 1902. Two peach scales. Fla. Agr. Exp. Sta. Bull. 61:
Merrill, G. B. 1922. Lady beetles of Florida. State Plant Board of Fla.
Quart. Bull. 6(2) :1-46.
Muma, M. H. 1955. Factors contributing to the natural control of citrus
insects and mites in Florida. Jour. Econ. Ent. 48:332-338.
Muma, M. H. 1959. Natural control of Florida red scale on citrus in
Florida by predators and parasites. Jour. Econ. Ent. 52:577-586.
Riddick, Eloise. 1955. Check list of hosts of scale-insects of Florida. State
Plant Board of Fla. Bull. 7:1-78.
Simmonds, F. J. 1958. The oleander scale, Pseudaulacaspis pentagon
(Targ.), (Homoptera, Coccidae) in Bermuda. Bermuda Dept. Agr.
Bull. 31:1-43.



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Hughes: Natural Enemies of the White Peach Scale 93

brachius neotropicalis (Kirkaldy 1909), earlier known by the preoccupied
name serripes (Fabr. 1803), is widely distributed in the Neotropical Region,
including the West Indies, but has not been reported heretofore from the
United States. I have recently seen a male and a female from Miami,
Florida, in the collection of the State Plant Board of Florida. These were
taken in traps, situated about 5 miles apart, on November 23 and November
25, 1959, respectively.
P. neotropicalis is nearly twice as large (9/2 to 10 mm.) as the largest
Pachybrachius reported previously from the United States, and is further
distinguished easily by the much more slender front femora and the blackish
pronotum with four very small, rusty spots on the posterior lobe. As in
P. albocinctus Barber, the basal portion of the fourth antennal segment is
very broadly white.-ROLAND F. HUSSEY, Biology Department, University
of Florida, Gainesville.

Word has recently been received of the death of J. William Decker, 76
years of age. Mr. Decker was associated with the Fort Clinch State Park
for 19 years and was responsible for the development of the excellent
museum associated with the old fort. Last year he retired from the State
Park Service and was engaged in the development of a private museum at
Fernandina Beach at the time of his death. He is survived by his wife,
Mrs. Sadie Decker, and son, Douglas William Decker, who plan to complete
and operate the private museum. Mr. Decker trained as an engraver and
silversmith in Germany as a young man. In addition to his many historical
interests, he was a naturalist in the very broadest sense. His interest in
insects is evident from his many years of membership in Florida Entomo-
logical Society.

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