Official Organ of the Florida Entomological Society
VOL. XVII DECEMBER, 1933 No. 4
A STUDY OF INSECT POPULATIONS ON CELERY IN THE
SANFORD, FLORIDA, DISTRICT
C. B. WISECUP, Assistant Entomologist
Truck Crop and Garden Insect Investigations
R. L. MILLER, Associate Entomologist
Fruit and Shade Tree Insect Investigations,
Bureau of Entomology,
United States Department of Agriculture.
The major attention of entomologists concerned with celery
pests has been directed toward those insects which cause ap-
preciable damage, such as the celery leaf tier, aphids, cutworms,
loopers, etc. No systematic survey to determine the general
abundance of insects on Florida celery had been made until
January 1929, when the junior author, while connected with the
Florida State Plant Board, began such studies on the spring,
or so-called "late", crop of celery. It was thought that such a
survey would show what insects were potential celery pests and
might yield information useful for predicting outbreaks. In
addition, such information would give a better idea of the im-
portance of natural control and show the seasonal distribution
of the insects. In the fall of 1929, when the junior author was
transferred to the Mediterranean fruit fly investigations, the
studies were taken up by the senior author, beginning soon
after celery became established in the field and continuing until
the end of the crop season.
Celery (Apium graveolens) is a winter crop in Florida. It is
grown most extensively on the sandy soil of the St. Johns River
valley near Sanford in an area 10 miles long by 3 miles wide.
This limited area comprises about 3,500 acres of cultivated land
which bears a crop of celery some time between September and
the following May each year. The seed beds are started in late
THE FLORIDA ENTOMOLOGIST
July and August and the first plants are set in the field about
September 1. Later plantings follow regularly until some time
in January. Harvesting reaches its peak in February and March
and declines rapidly through May.
Five 1-acre plots were selected on representative farms, the
celery on each plot being in a different stage of growth. Starting
on January 20, 1929, a collection on each plot was made every
Monday and Thursday until all the celery on that plot was
For the second season, 1929-30, similar collections on three
plots were initiated on October 14, and other plots were included
in the collections as those on the original plots were discontinued
owing to their crops having been harvested. In all, eight plots
were included in that season's work.
As a rule two men made the collections, starting as soon as
the dew had dried from the celery. Each man made 100 sweeps
with a 12-inch net on each plot, crossing two rows of celery at
each sweep and zigzagging across the field.
All of the collected insects were shaken to the small end of
the net and emptied into labelled 1-quart killing jars. The nets
were carefully examined and counts made of all adhering insects.
At the close of the day's collecting the contents of the various
jars were carefully counted and tabulated. The insects were
first classified as to orders and then those orders in which the
more important economic forms are found were further sub-
divided. Thus, in the tables the celery leaf tier and garden flea
hopper are treated equally with the orders Diptera and Thysan-
optera. Red spiders, though not insects, were recorded because
of their economic interest. Common field spiders were recorded
because of their predaceous habits.
COMPARISON OF CLIMATIC CONDITIONS FOR THE TWO SEASONS
The temperature for the first season was very near normal
until January, when the average mean temperature rose about
three degrees above normal and remained so until May (fig. 1).
The average mean temperature for this entire celery season was
68.90F., while the normal average is 65.50F. (table I, A). The
rainfall was much below normal for each month except May,
the total precipitation being only 8.44 inches, which is 12.17
inches less than the normal of 20.61 inches. In contrast to this
VOL. XVII-No. 4 55
season, the following season was almost normal. The extremes
of temperature compensated for each other so that the departure
from the normal was only +1.50. Figure 1 shows the wide
fluctuations in mean temperature from month to month during
this season. Rainfall for this period totalled 6.04 inches more
than the normal, most of which fell in November and March.
Table I, B shows a comparison of the spring, or late-crop, season
of the two years. It will be noted that the precipitation for
1929 was 4.94 inches less than normal and the temperature was
50F. higher than normal, whereas the 1930 spring had 6.51
inches more rainfall than normal and a mean temperature of
only 1.4F. above normal. These differences in precipitation
and temperature were found to have a direct bearing on the
insect population of the celery fields for the two seasons. In
addition to showing the variations from normal of the tempera-
ture and precipitation for the crop seasons, figure 1 shows the
duration of the survey for each of the two years and, from the
relative heights of the two cross-hatched areas, gives an idea
of the number of collections made each season.
SEPT OCT NOV DEC JAN FEB MAR APR MAY JUNE
2 70 -- 1929-30 1928-2- -
Fig. 1.-Prevailing climatic conditions for duration of insect surveys on
celery at Sanford, Fla.,. 1929-30. The large, superimpcsed, cross-
hatched areas in the center of the chart show the seasons during
which the surveys were made, the relative height giving a com-
parison of the number of collections made each season.
THE FLORIDA ENTOMOLOGIST
TABLE I.-COMPARISON OF WEATHER DATA FOR THE SANFORD, FLA., DIS-
TRICT, SEASONS OF 1928-29 AND 1929-30.
Total rainfall (in.)....
Av. mean temp. (F.)
A. Entire Survey Period B. Spring Crop Season
(October to April) (January to April)
1928-29 Average 1929-30 1928-29 Average 1929-30
8.44 20.61 26.25 5.04 9.98 16.49
-12.17 -...... +6.04 -4.94 .......... +6.51
68.9 65.5 67.0 69.4 64.4 65.8
+3.4 -. +1.5 +5.0 -....... +1.4
COMPARISON OF INSECT POPULATIONS FOR THE TWO SEASONS
Table II shows the average number of insects caught per
1,000 sweeps from January 20 to April 24 for each of the two
years. As shown in figure 1, the spring collections were con-
tinued in 1930 for about two weeks longer, but for the compari-
son of the two seasons only those collections made within the
same dates as limited the 1929 survey were used. For this
reason the figures used for the 1930 infestation in table II are
not the same as those used later in table III, where the collections
for the entire spring period are included.
Not all of the insects which were collected are listed here, the
Orthoptera, weevils, and Odonata being omitted because so few
were captured in the spring of 1929.
TABLE II.-COMPARISON OF INSECT POPULATIONS PER 1,000 SWEEPS DURING
SPRING SEASONS (JANUARY 20 TO APRIL 24) OF 1929 AND 1930.
The first column of figures for
position based on numbers collected.
each year refers to the relative
D iptera ..................................
Red spiders .......................
Garden flea hopper ............
Other spiders .................
Looper larvae .......-- ..........
Miscellaneous Coleoptera ..
Celery leaf tier ......-..........
Number of collections .......
1930 (approx.) 1930
The insects have been arranged in order of abundance as
found in 1930. The last column gives a rough approximate ratio
VOL. XVII-No. 4
of the numbers for the two seasons. An important economic
group, the Noctuidae, except for the celery looper, is not rep-
resented in these findings, as the habits of both adults and larvae
of the remainder of this family are such that they were not
captured by sweeping. Thysanoptera stand at the top of the
list and were about equally abundant in the two seasons. Various
types of Diptera, which ranked second in 1930, ranked fourth
in 1929 and were only half as abundant. Aphids ranked third
in both years but were three times as abundant during the first
year's survey as during the second. Red spiders were fourth
on the list in 1930, but the warm dry spring of 1929 caused them
to be four times as abundant as in 1930 and to rank second.
The remaining insects maintained about the same relative
order during the two years, though the actual numbers present
varied considerably as shown by the ratios. While the Hymenop-
tera stood ninth and sixth, respectively, in 1929 and 1930 the
total number counted was six times as great for the second
season as for the first. Leafhoppers, which ranked eighth in
1929 and fifth in 1930, also had a ratio of 1 to 6. Miscellaneous
Hemiptera held nearly the same position during the two years
but had a ratio of 1 to 5. Miscellaneous Coleoptera, with a ratio
of 1 to 4, had about the same rating. Celery leaf tier adults,
standing tenth and thirteenth in the lists, were twice as abun-
dant in 1929 as in 1930. The most striking feature of the survey
was the similarity of the total number of insects for the two
seasons, the ratio of which was 1.25 to 1.
The bad outbreaks of aphids and red spiders in 1929 are
indicated in the 3-to-1 and 4-to-1 ratios of these insects. The
large number of thrips present each season did not result in any
apparent damage to celery. The 2.4-to-1 ratio of celery leaf tier
adults marks the serious outbreak of this insect in 1929. The
main factor accountable for this was the continued warm weather
of 1929 (fig. 1), which allowed a building up of numbers, whereas
in 1930 the warm January and February was followed by a
March much below normal. This continued mean temperature
of about 640F. in March 1930 prevented the rapid development.
of the celery leaf tier until after the bulk of the celery had been
COMPARISON OF INSECT POPULATIONS IN FALL AND SPRING
After the comparison of the insect populations for the spring
season of the two years, the question naturally arises as to what
a comparison of the insect populations on the fall and spring
THE FLORIDA ENTOMOLOGIST
crops would reveal. Table III shows the results of the counts
made during the two parts of the crop season of 1929-30.
As already explained, the figures for the spring collections
are not the same as those used in table II, as it was desired in
that case to make the comparison from collections limited to
the same period. The Diptera (including all flies, parasitic and
non-parasitic) ranked first, with an average of 896 for the entire
season, but with an average of 1,155 in the spring. This showed
about twice as many flies in the spring as in the fall. The great
abundance of Tysanoptera in the spring caused these insects to
rate second for the entire season. Red spiders were very much
in evidence in the spring, even though they were much less
abundant than in 1929. Aphids, ranking third, were most numer-
ous during the fall and winter when over 70 per cent of the
total were captured.
TABLE III.-COMPARISON OF INSECT POPULATIONS OF THE SPRING SEASON
WITH THOSE OF THE FALL SEASON AND THOSE OF THE ENTIRE CROP
Red spiders ........
Other spiders ....
Celery leaf tier..
W eevils ..............
Number of collections 1 253 1 121 | 132 1
VOL. XVII-No. 4
Of the 19 groups of insects tabulated, 13 were more abundant
in the spring. Outstanding among these are the Thysanoptera,
with 60 times as many in spring as fall; red spiders, with 8 times
as many; loopers, with 5 times as many; coccinellid beetles,
with 6 times as many; and the celery leaf tier, with 15 times
SEASONAL OCCURRENCE OF ECONOMIC FORMS
This method of regular collections makes possible a rather
accurate graphic presentation of the numbers of insects present
during each season. In figures 2, 3 and 4 is shown a comparison
of the seasonal abundance of the more important economic
groups. The upper half of each chart shows the seasonal varia-
tion during the spring of 1929, and the lower half presents the
results found during the entire season of 1929-30. The charts
have been drawn semilogarithmically to give greater emphasis
to those insect groups having only a small number present. The
points for the graphs, with the exception of the celery leaf tier
in figure 4, are the averages for each half month, including all
plots under survey at that time irrespective of the size of the
Figure 2 shows the waves of aphids which occurred during
the crop seasons, with their biologically related predators and
parasites. Not all of the captured Hymenoptera were parasites
of aphids but a large majority were. The lag in development of
the parasites and predators during the cool weather of November
and December of 1929 was so great that insecticidal control
measures were used by practically all growers. However, in the
spring the aphid outbreak was abruptly terminated in late April
by natural control. No records have been kept of the syrphids,
as the adults usually eluded the net, and the larvae were not
readily swept from the plants.
The more numerous forms of sucking insects, including Thy-
sanoptera (thrips), have been grouped in figure 3. In 1930 the
Thysanoptera did not start building up until late in January but
they were present in great numbers during April. Leafhoppers
were very abundant during the fall of 1929, apparently coming
into the celery from the adjacent grass lands and ditch banks
and, while they increased somewhat in number during the spring,
their presence was much less noticeable than in the fall.
The adults and nymphs of the garden flea hopper (Halticus
Fig. 3.-Seasonal occurrence on celery
of insects of the sucking type
Fig. 4.-Seasonal occurrence of the
most injurious insects on celery.
Fig. 2.-Seasonal occurrence of aphids
on celery, with parasites and preda-
VOL. XVII-No. 4
citri Ashm.) were quite abundant on nearly mature celery in
the spring of 1929, causing some very pronounced damage. A
heavy infestation was carried over to the celery seed beds in late
summer and fall. However, when the plants were set in the
field the rate of increase was not continued, and no damage was
noticed in 1930. The various other Hemiptera noted during the
seasons have been tabulated under that general term. These
rarely became sufficiently abundant to be noticed.
Figure 4 shows the insects which are normally the most
injurious and which attract the attention of the growers. The
celery leaf tier (Phlyctaenia rubigalis Guen.) is always a poten-
tial pest of great economic importance and did much damage
in 1929. Since more reliable and extensive data concerning the
abundance of celery leaf tier adults were available as the result
of other investigations these were used in this graph instead
of the survey records. Three definite broods of the moths were
noted from February to May of both seasons, but the greater
number present in 1929, and the piling up of broods, resulted
in serious injury that year. Conditions appeared to be even
more favorable for the insect in 1930. Though the February
brood of adults was smaller than in 1929 it was earlier, and
great damage could have resulted if the following cold weather
had not prevented larval development until harvesting was
Red spiders are somewhat of a menace during the winter,
as this is usually the season of minimum rainfall. The warm,
dry season of 1928-29 allowed them to build up to destructive
numbers despite vigorous control measures. Likewise, in 1929-
30 they were building up vigorously until halted by the heavy
rains of March.
The celery looper (Autographa falcifera Kby.) and the cabbage
looper (Autographa brassicae Riley) are present throughout the
season, gradually building up to rather serious numbers by late
spring. Whenever they become very abundant disease and para-
sites become such a very evident limiting factor that the growers
pay little attention to them.
Very incomplete records 'of the Noctuidae were secured by
sweepings. During the spring of 1929 bait pans were used to
supplement the sweepings, and the record of Noctuidae secured
therein has been included. No effort was made to record these
insects during the second season.
THE FLORIDA ENTOMOLOGIST
SUMMARY AND CONCLUSIONS
One of the most obvious conclusions that can be drawn from
these studies is the fact that the insects most abundant in the
celery fields are not those most destructive there. Thysanoptera
and Diptera, which together comprise more than half of the
entire insect population, are of little economic importance.
Aphids, ranking third in 1929-30, are not considered as serious
a pest as some other insects and usually little money is spent
for their control. Red spiders, ranking second in 1928-29 and
fourth in 1929-30, are sometimes very troublesome. The celery
leaf tier, which has done by far the most commercial damage,
ranked only tenth and thirteenth in abundance, and in the year
of greatest abundance the adults captured comprised only 0.25
per cent of the entire population collected.
Prediction of outbreaks of destructive celery insects is possible
only in a very general way, depending on accurate records of
climatic conditions and knowledge of the initial populations. In
comparing the two seasons it is apparent that climatic conditions
determine the abundance of the various insects. Red spiders,
for example, were four times as abundant during the dry season
as during the wet. Aphids were also three times as numerous
during a dry year as during one of normal rainfall. Aphids
thrive best on celery in the cool, dry period of fall when parasites
and the fungus Empusa sp. are least abundant. Two groups of
sucking insects were five or six times as abundant during the
rainy season as during the dry season, probably because the
foliage was more attractive and rainy weather was not unfavor-
able for their survival. The celery leaf tier was more abundant
during the dry season, but this is due more to the high tempera-
ture than to the dry weather.
Keeping in mind the factors just mentioned, the growers
should be able to ascertain with some degree of certainty just
what insects will require control measures. If the warmth of
the season is above the average, the celery leaf tier will probably
cause trouble. If the season is dry and warm, red spiders will
become abundant. A cool fall is usually followed by destructive
aphid outbreaks in December.
Official Organ of The Florida Entomological Society, Gainesville,
VOL. XVII DECEMBER, 1933 No. 4
J. R. W ATSON ................-..-..-............-......................................Editor
E. W. BERGER..................------... ...........---..-... -Associate Editor
H. E. BRATLEY ..--.............------ .....-- ..--.-.......... Business Manager
Issued once every three months. Free to all members of the
Subscription price to non-members is $1.00 per year in ad-
vance; 35 cents per copy.
TWO NEW SPECIES OF OEDALEOTHRIPS
WITH NOTES ON OTHER SPECIES
By J. R. WATSON
(Continued from Vol. XVII, No. 3, page 50)
Oedaleothrips jacksoni Hood was described (Ent. News XXVI,
May, 1925) from a single female taken on a limb of Mountain
Mahogany (Cercocarpus panifolius Nutt.) in Colo. There seems
to be no record of any further captures. The writer has received
from Mr. H. B. Wells of the Dept. of Ent., Texas Agric. Exp.
Station, six specimens taken by him at Waco, Texas on dry bark
on Aug. 14, 1933.
Three of these are males and as the male does not seem to
have been described, description follows.
Oedaleothrips jacksoni Hood
Length 2 mm. Color black with brown legs, the same as the female.
In my specimens, both male and female, the third antennal segment, as
well as the first and second, is tinged with brown. Head as in female,
antennae 1.5 times as long as head. Fore femora greatly enlarged, width
across base greater than that of the base of the head, strongly arched, apex
on the inside bright yellow. Tarsal tooth long and stout (tho not nearly
as long as in 0. hubbelli Watson) slightly recurved at apex. Abdomen
much smaller, especially shorter. Otherwise as in female.
Measurements: Total body length 2.04 mm. Head, length .44 mm.,
width .30 mm.; prothorax, length .23 mm., width .36 mm.; pterothorax,
width .30 mm.; abdomen, greatest width .60 mm.; tube, length .16 mm.,
width at base .106 mm., at apex .475 mm. Antennal segments, length
(width). I, 48 (44); II, 70 (38); III, 163, varies greatly, from 154 to 172
(41) ; IV, 110 (41); V, 101 (36); VI, 82 (33); VII, 59 (27); VIII, 47 (20).
THE FLORIDA ENTOMOLOGIST
Nymph. Body length 1.19 mm. Head, including antennae, legs, and
last two abdominal segments dark brown, thorax and remainder of abdo-
men colored bright red by hypodermal pigment between ivory colored spots
which cover nearly half of the abdomen. These spots cover the posterior
angles of the prothorax, the sides of both mesothorax and metathorax.
There are also large blotches in the median line of the meso- and meta-
thorax. Abdominal segments 1 and 2 are free of spots but 3 bears four
large ones and 6 to 9 bear a dorsal row. Segments 4 to 6 bear 4 longi-
tudinal white bands, more clear and transparent than the ivory colored
spots. Head a little longer than wide. Antennae 7-segmented. Apex of
segment 2 with a light spot.
0. hubbelli Watson is closely related to jacksoni. The third
antennal segment is usually brown but in one male it is yellow
as in jacksoni. Better characters to separate them are the shape
of the head, eyes, and tarsal tooth and the comparative lengths
of the head and prothorax. The following key will seem to
separate these species.
a. Tube yellow. -Texas. hooker Hood.
aa. Tube black.
b. Head much longer than wide, sharply narrowed posteriorly, wider
than pterothorax, white blotches on abdomen; at most only an-
tennal segments 1-3 yellow.
c. Antennal segments 1 and 2 yellow; head about 1.5 times as
long as broad.
d. Abdominal segment 1 brownish yellow, large ivory
colored blotches on segments 2, 4, and 5; antennal seg-
ment 1 considerably longer than wide, 3 dark brown.
-Fla. querci Watson.
dd. At least part of abdominal segment 1 white, antennal
segment 3 yellow or light brown.
e. Head widest behind the eyes, prothorax less than
half as long as head; tarsal tooth directed forward,
eyes prolonged on ventral side.
-Col., Texas. jacksoni Hood.
ee. Head widest across the eyes, prothorax more than
half as long as head; tarsal tooth recurved, eyes
not prolonged on ventral side.
-Okla. hubbelli Watson.
cc. Antennal segments 1 and 2 mostly blackish brown, much
darker than 3; head nearly twice as long as wide.
-Argentina. walteri n. sp.
bb. Head about as wide as long, narrower than pterothorax; no white
blotches on abdomen; at least antennal segments 2-4 yellowish.
-Iowa. andrei n. sp.
VOL. XVII-No. 4
MINUTES OF THE FLORIDA ENTOMOLOGICAL SOCIETY
January 13, 1933
President Tissot called the meeting to order at 4:10 P.M. in
Room 305, Agriculture Building.
The following members were present: Mr. Calhoun, Mr.
Rowell, Mr. Kea, Professor Watson, Professor Byers, Professor
Dickey, Dr. Tissot, Mr. Bratley, and Professor Creighton. There
were also several visitors in the audience.
Dr. Tissot introduced Professor Watson as the speaker for
the day. Professor Watson delivered an extremely interesting
paper on Thysanoptera distribution. He named many of the
outstanding thrips and gave their regional distribution. He
also gave several factors that might possibly limit the spread-
ing of some species. The speaker also gave some points concern-
ing the structure and the life history and habits of the Thrips
After the presentation of this address, the members of the
society were permitted to ask the speaker questions concerning
the Order Thysanoptera.
The president announced that the secretary had obtained Dr.
Mark F. Boyd, Anophelene Mosquito expert, for an address be-
fore the society at 4 P.M. Friday, February 10. The meeting to
be held in the large lecture room on the first floor of the Agri-
An announcement was then made by Mr. Bratley, the Business
This being the regular meeting for the election of officers,
the following men were duly elected:
Business Manager-Mr. Bratley
Editor of The Florida Entomologist-Professor Watson
Assistant-Editor of The Florida Entomologist-Dr. Berger
JOHN T. CREIGHTON.
THE FLORIDA ENTOMOLOGIST
FOOD HABITS OF TINEOLA UTERELLA*
By J. W. KEA
The moth, Tineola uterella Walsingham, which has been
present in Florida for a number of years, is apparently becoming
more abundant, especially in the southern part of the state. The
larva constructs about itself a bag-like covering which is gray
in color, about 10 to 12 mm. in length, and with the general
shape of a cantaloupe seed. These bags are quite conspicuous
when on the walls of a house or other places which they frequent.
All available references state that this insect is strictly harm-
less, feeding only on the dried remains of insects in spider webs,
etc. However, numerous complaints of householders led to a
series of observations on their food habits. They refused to
eat dried insects when limited solely to them in the laboratory,
but upon examining the cases of specimens sent in from various
places in the state very minute portions of dried insects were
found, thus indicating that this is sometimes an article of their
diet. Likewise, they did not eat cotton. However, when offered
woolen threads and woolen cloth they ate eagerly. Numerous
complaints of their depredations on rugs and other woolen
fabrics have been received.
An adult female was reared by the writer in the laboratory
of the Department of Entomology, Florida Agricultural Experi-
ment Station, and sent to the U. S. Nat. Museum for identifica-
tion. The adult is extremely rare and as far as the writer has
been able to determine this is the only adult specimen ever taken
Although evidence of the attack of a parasite was quite
common on many larvae, only one specimen, a hymenopterous
parasite, was obtained. This has not as yet been determined.
*Contribution from the Department of Entomology, Florida Agricultural
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