The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
site maintained by the Florida
Cooperative Extension Service.
Copyright 2005, Board of Trustees, University
Bulletin 271 September, 1934
UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATION
Wilmon Newell, Director
THE ASPARAGUS CATERPILLAR:
ITS LIFE HISTORY AND CONTROL
By J. W. WILSON
Fig. 1.-Adult asparagus caterpillar, Laphygma exigua Hbn.
Bulletins will be sent free to Florida residents upon application to
AGRICULTURAL EXPERIMENT STATION
EXECUTIVE STAFF BOARD OF CONTROL
John J. Tigert, M.A., LL.D., President of the Geo. H. Baldwin, Chairman, Jacksonville
University A. H. Blanding, Bartow
Wilmon Newell, D.Sc., Director A. H. Wagg, West Palm Beach
H. Harold Hume, M.S., Asst. Dir., Research Oliver J. Semmes, Pensacola
Harold Mowry, M.S.A., Asst. Dir., Adm. Harry C. Duncan, Tavares
J. Francis Cooper, M.S.A., Editor J. T. Diamond, Secretary, Tallahassee
R. M. Fulghum, B.S.A., Assistant Editor
Jefferson Thomas, Assistant Editor
Ida Keeling Cresap, Librarian BRANCH STATIONS
Ruby Newhall, Administrative Manager
K. H. Graham, Business Manager NORTH FLORIDA STATION, QUINCY
Rachel MeQuarrie, Accountant
L. O. Gratz, Ph.D., Plant Pathologist in
MAIN STATION, GAINESVILLE R. R. Kincaid, Ph.D., Asso. Plant Pathologist
J. D. Warner, M.S., Agronomist
AGRONOMY R. M. Crown, B.S.A., Asst. Agronomist
W. E. Stokes, .S., Agronomist Jesse Reeves, Farm Superintendent
W. E. Stokes, M.S., Agronomist"*
W. A. Leukel, Ph.D., Agronomist CITRUS STATION, LAKE ALFRED
G. E. Ritchey, M.S.A., Associate*
Fred H. Hull, M.S., Associate John H. Jefferies, Superintendent
W. A. Carver, Ph.D., Associate Geo. D. Ruehle, Ph.D., Associate Plant
John P. Camp, M.S., Assistant Pathologist
W. A. Kuntz, A.M., Assoc. Plant Pathologist
ANIMAL HUSBANDRY B. R. Fudge, Ph.D., Associate Chemist
W. L. Thompson, B.S., Asst. Entomologist
A. L. Shealy, D.V.M., Animal Husbandman**
R. B. Becker, Ph.D., Dairy Husbandman EVERGLADES STATION, BELLE GLADE
W. M. Neal, Ph.D., Associate in Animal
Nutrition A. Daane, Ph.D., Agronomist in Charge
D. A. Sanders, D.V.M., Veterinarian R. N. Lobdell, M.S., Entomologist
M. W. Emmel, D.V.M., Asst. Veterinarian F. D. Stevens, B.S., Sugarcane Agronomist
W. W. Henley, B.S.A., Asst. Animal Hus- G. R. Townsend, Ph.D., Asst. Plant Patholo-
P. T. Dix Arnold, B.S.A., Assistant Dairy B. A. Bourne, Ph.D., Sugarcane Physiologist
Husbandman J. R. Neller, Ph.D., Biochemist
R. W. Kidder, B.S., Asst. Animal Husband-
CHEMISTRY AND SOILS man
SW R P Ross E. Robertson, B.S., Assistant Chemist
R. W. Ruprecht, Ph.D., Chemist**
R. M. Barnette, Ph.D., Chemist SUB-TROPICAL STATION, HOMESTEAD
C. E. Bell, Ph.D., Associate
H. W. Winsor, B.S.A., Assistant H. S, Wolfe, Ph.D., Horticulturist in Charge
H. W. Jones, M.S., Assistant W. M. Fifield, M.S., Asst. Horticulturist
Stacy O. Hawkins, M.A., Assistant Plant
ECONOMICS, AGRICULTURAL Pathologist
C. V. Noble, Ph.D., Agricultural Economist** WEST CENTRAL FLORIDA STATION,
Bruce McKinley, A.B., B.S.A., Associate ROOKS
Zach Savage, M.S.A., Associate BROOKSVILLE
A. H. Spurlock, M.S.A., Assistant W. F. Ward, M.S.A., Asst. Animal Husband-
man in Charge'
ECONOMICS, HOMEn in ha
Ouida Davis Abbott, Ph.D., Specialist**
L. W. Gaddum, Ph.D., Biochemist FIELD STATIONS
C. F. Ahmann, Ph.D., Physiologist
J. T. Hall, Jr., B.S.Ch.E., Asst. Physiologist Leesburg
ENTOMOLOGY M. N. Walker, Ph.D., Plant Pathologist in
J. R. Watson, A.M., Entomologist** W. B. Shippy, Ph.D., Asso. Plant Pathologist
A. N. Tissot, Ph.D., Associate K. W. Loucks, M.S., Asst. Plant Pathologist
H. E. Bratley, M.S.A., Assistant J. W. Wilson, Ph.D., Associate Entomologist
J. W. Kea, B.S.A., Assistant C. C. Goff, M.S., Assistant Entomologist
HORTICULTURE Plant City
A. F. Camp, Ph.D., Horticulturist** A. N. Brooks, Ph.D., Plant Pathologist
G. H. Blackmon, M.S.A., Horticulturist R. E. Nolen, M.S.A., Asst. Plant Pathologist
A. L. Stahl, Ph.D., Associate Cocoa
F. S. Jamison, Ph.D., Truck Horticulturist
R. J. Wilmot, M.S.A., Specialist, Fumigation A. S. Rhoads, Ph.D., Plant Pathologist
R. D. Dickey, B.S.A., Assistant Horticulturist A. H. Eddins, Ph.D., Plant Pathologist
PLANT PATHOLOGY Monticello
W. B. Tisdale, Ph.D., Plant Pathologist** G. B. Fairchild, M.S., Assistant Entomologist
George F. Weber, Ph.D., Plant Pathologist
R. K. Voorhees, M.S., Assistant Bradenton
Erdman West, M.S., Mycologist David G. Kelbert, Asst. Plant Pathologist
Lillian E. Arnold, M.S., Assistant Botanist
*In cooperation with U.S.D.A. E. R. Purvis, Ph.D., Assistant Chemist,
"* Head of Department. Celery Investigations
THE ASPARAGUS CATERPILLAR: ITS LIFE HISTORY
By J. W. WILSON
Several species of caterpillars belonging to the cutworm
family (NOCTUIDAE) occur in the ferneries of Florida and
are responsible for more or less injury. Some of these species
belong to the semi-tropical army worm group, some to the army
worm group, and some to the cutworm group. The asparagus
caterpillar, Laphygma exigua Hbn., belongs to the same genus
as the fall army worm. This species is kery abundant in the
ferneries north of Auburndale but has not been recorded south
of that point. Although this bulletin is concerned only with the
asparagus caterpillar, much of the information concerning the
life history, natural enemies and control measures are applicable
to other species of the semi-tropical army worm group which
attack Asparagus plumosus.
The asparagus caterpillar is known in the Western States
as the sugar beet army worm. In Florida this insect confines
itself almost entirely to Asparagus plumosus var. nanus as a food
plant. Thus it is known to the growers of A. plumosus as the
fern caterpillar and the bud worm. The latter name is applied
to the first and second stage larva because of its habit of climbing
to the bud and chewing a hole at the base of the tender tip.
The first record of the asparagus caterpillar in the United
States is the description and notes by Harvey (5)1 in 1876.
Harvey collected specimens of this insect in Oregon and Cali-
fornia. Larvae were collected in California by Coquillett (Chit-
tenden, 2) in 1882 and 1886. In 1899 Gillette (4) reported the
larvae feeding on sugar beets in Colorado. Sanderson (7) re-
ported the larvae damaging cotton in Texas in 1904. Marsh
(Campbell and Duran, 1) reported a serious outbreak on sugar
beets in Kansas in 1911, and observed a few larvae on turnips
at Phoenix, Arizona in 1916. In a letter Dr. Foster H. Benja-
min states that this insect is often confused with the fall army
worm and probably for this reason escapes detection. According
to Dr. Benjamin the asparagus caterpillar is abundant as far
east as Brownsville, Texas, and was collected at Quincy, Illinois
1 Italic figures in parentheses refer to "Literature Cited" in the back
of this bulletin.
4 Florida Agricultural Experiment Station
in 1899, and at Altamonte Springs, Florida in 1924. Mr. J. M.
Langstron of the State Plant Board of Mississippi writes that
he has specimens in the collection which were taken at A. & M.
College and Starkville, Mississippi in August 1920. Larvae of
the asparagus caterpillar were also collected feeding on corn at
Natchez, Mississippi on May 14, 1931.
Although we have no accurate record of the first appearance
of the asparagus caterpillar in ferneries in Florida, it is certain
that this insect has been present for a number of years. Speci-
mens sent to the United States National Museum during the
summer of 1932 wele identified by Dr. Benjamin. At the pres-
ent time this pest occurs at Pierson, DeLand, Fort McCoy, Lees-
burg, Yalaha, Groveland, Fern Park, Altamonte Springs and
Auburndale. It has not been found south of Auburndale, al-
though ferneries there are infested with species of the related
Prodenia group which are as destructive as the asparagus cater-
FOOD PLANTS AND NATURE OF DAMAGE
Eighteen plants are listed by Campbell and Duran (1) as
hosts for the asparagus caterpillar. This list includes sugar
beets, table beets, corn, cotton, peas, pepper and a number of
wild plants and grasses. DeOng (3) reports the larvae feeding
on the upper surface of castor bean leaves. The larvae attack
the leaves of plants in the blooming stage and feed beneath a
protecting web. In Florida this insect is rarely found on plants
other than Asparagus plumosus though it has been observed
feeding on wild grasses and gladiolus. Taylor (8) reports that
in South Africa tobacco, grapes, young eucalyptus trees, and
lawns, as well as cotton, maize and peas are attacked by this
The first and second stage larvae climb to the asparagus bud
and chew a hole at its base. Frequently, three or four larvae
will be found on the same bud. These holes cause the bud to
curl over and so deform the young sprays that they are not
salable. The older larvae will feed on all parts of the plant, but
prefer the more tender sprays which have just begun to feather
It is difficult to estimate the amount of damage inflicted by
the asparagus caterpillar because of the fluctuations in the
market value of A. plumosus during the summer, and because
of the variable thoroughness with which control measures are
The Asparagus Fern Caterpillar 5
applied. The greatest injury occurs during the rainy season
which usually lasts from eight to 12 weeks between mid-June
or July and September. During much of this period some rain
falls almost every day; frequently the amount is as much as one
inch in an hour. These frequent and heavy rains make it diffi-
cult to keep the plants covered with an insecticide. Thus the
damage multiplies with increased rainfall (see Table 2 for rain-
fall records). The caterpillars frequently become abundant
enough to destroy completely a crop if control measures are
not initiated promptly.
LIFE HISTORY AND HABITS
The life history and habits of the asparagus caterpillar in
California have been discussed by Campbell and Duran (1), and
by Chittenden (2). Notes on the life history and habits in
Florida were published by Wilson (11) in 1932.
No migration such as has been described for the fall army
worm has been observed for either the adults or larvae of the
asparagus caterpillar. Unlike the fall army worm, this species
is able to pass the winter in colder climates, and does not have
the seasonal migrations characteristic of the fall army worm.
Emergence of the adult moths (Fig. 1) occurs during the
night. Mating may take place soon after the adult arrives at
the soil surface, as is shown by the fact that fertile eggs have
been deposited in the laboratory cages the evening following
that of emergence. Practically all of the activities occur at
night, although the moths may be observed flying through the
fernery in the daytime. The eggs are laid in masses, usually
on the underside of the fern spray. These masses are covered
over with scales from the female's body. Such egg masses are
frequently confused with spider egg masses by growers.
Growers should make an effort to familiarize themselves with
the egg masses for they are one of the first indications that an
attack by the caterpillar is impending. When large numbers
of the egg masses are observed, a heavy infestation of the larvae
is to be expected in two or three days. When young plants are
scarce, egg masses have been observed on dead and dry stems
left in the fernery.
Egg masses collected in the fernery contained from 50 to 150
eggs, while masses deposited in the laboratory cages ranged
from 5 to 145 eggs. The largest number of eggs deposited by
a single female was 1,321 and the smallest number was 18.
6 Florida Agricultural Experiment Station
The average number of eggs for 88 females reared during the
course of this work was 604.66 per moth. The eggs (Fig. 2) are
ordinarily deposited in adjoining
rows and may be placed in one
or two layers and are usually
covered with whitish scales. The
Masses are irregular in shape.
"I The cannibalistic habits of the
i fall army worm are well known,
but, from the author's observa-
Fig. 2.-Egg of the asparagus tions, the asparagus caterpillar
caterpillar, greatly enlarged. (Figs. 3 and 4) does not have
Original. this habit to such a high degree.
As many as four larvae have been reared without mishap in a
two ounce seamless tin box provided with plenty of food. If
food becomes scarce, some larvae will devour others.
During the summer months the pupal cell is formed near the
surface of the soil-in most cases no deeper than one-fourth
inch. Full grown larvae were observed to crawl around over the
surface of the soil for a few minutes.
tT J Tmn When a satisfactory place was locat-
"ed, grains of sand were picked up
between the jaws and placed in a
1 curved line around the larva. The
Fig. 3.-Newly hatched sand particles were gradually piled
larva of the asparagus
caterpillar. Original. (Line up over the larva and were glued
beneath represents 1/25 together by a sticky secretion from
inch x 40.) the mouth. The cells were gradually
closed in until only the rear of the larva was left exposed to view.
Two larvae completed this part of their cells in 30 minutes. The
larvae then crawled into their cells and filled in the opening.
The transformed pupa (Fig. 5) was found the following day.
The roofs of these cells were of a thickness of only a few grains
Fig. 4.-Full grown larva of the asparagus caterpillar. Original. (Line
beneath represents 1/25 inch.)
The Asparagus Fern Caterpillar 7
The asparagus caterpillar may be found in all stages during
every month of the year, but it is not easily found during Decem-
ber, January, February and March
because the lower temperatures of
these months slow up development
and also seem to make the larvae
more susceptible to a bacterial dis-
ease which greatly decreases the
number of larvae present in the fern-
eries. Although the eggs and larvae
may be found in numbers in April,
they are usually not abundant enough
to cause serious damage until the
latter part of May or June. During
June, July, August and September
when the larvae are very abundant
a close watch must be maintained in
the ferneries to prevent serious dam-
age. In some years the larvae will
be found in large numbers during
The asparagus ferneries furnish
ideal conditions for the development
of the asparagus caterpillar during ..'
all seasons of the year. Fresh young
foliage is almost always available for
the larvae and, since the soil is very
rarely cultivated, there is little dan-
ger of the pupae being destroyed.
The asparagus caterpillar breeds con-
tinuously during the winter months
though much more slowly than dur-
ing the summer months.
DURATION OF ADULT STAGE
After emergence there is usually pargus. 5upla of te Oina
a period of two or three days before (Line at side represents 1/25
egg laying begins, which is known as inch.)
the pre-oviposition period. In Table 1 the average duration of
the pre-oviposition period is tabulated for each month during
TABLE 1.-DURATION OF STAGES AND TOTAL DURATION OF LIFE FOR ADULT FEMALE AND MALE ASPARAGUS CATERPILLARS
OBSERVED AT LEESBURG, FLORIDA DURING 1932 AND 1933.
Ave. Duration Ave. Duration Ave. Duration Ave. Duration
Month Number of Preoviposition Oviposition Postoviposition Female Life Ave. Duration
SFemales Period in Days Period in Days Period in Days Male Life _
1932 | 1933 || 1932 1933 I 1932 ] 1933 II 1932 1933 ]| 1932 | 1933 j| 1932 F 1933
April ------------ 3 2.2 6.3 1.3 9.6 13.3.
A pril ......................... ........... 3 ............ 2 ............ 6.3 ............ 1.3 ..... 9.6 ... 13.3
M ay ............................ .......... 5 .. ....... 3.0 ---... 5.4 ... ..... .6 .......... 9.0 .. .. 10.2
June ............. .... 2 8 2.0 2.6 3.0 5.2 0.0 .5 4.0 8.3 2.0* 10.9
June---------------------- 2 8 2 26 30 5.2 00 583 20* 1.
Julyne ...----------------20 11 3.5 2.8 5.1 4.2 ..8 .2 9.4 7.2 9.9 8.3
August ...................... 16 3 2.6 2.7 4.9 3.7 .1 1.3 7.6 7.7 8.0 5.3
Septem ber ................ 7 ...... 1.9 ............ 4.1 ............ .2 -......-..- 6.2 ...... ..... 7.0 -
Sept* One individual........-------- 1- 41
TABLE 2.--AVERAGE MONTHLY MEAN, MEAN MAXIMUM, MEAN MINIMUM, HIGHEST AND LOWEST RECORDED TEMPERATURES,
AND RAINFALL AT LEESBURG, FLORIDA FOR THE YEARS 1932 AND 1933.
Month Mean Mean Maximum Mean Minimum Highest Lowest Rainfall
1932 | 1933 1932 1 1933 1 1932 | 1933 1| 1932 1 1933 | 1932 I 1933 11 1932 | 1933
January .................. 65.9 63.4 78.3 72.7 58.1 53.9 83 81 42 40 0.81 2.33
February ................ 68.1 66.5 78.9 76.4 61.0 56.9 85 85 45 37 0.34 2.94 c
March ...................... 61.4 65.5 72.6 79.4 51.8 53.5 86 88 34 40 4.97 1.58
April ...................... 69.4 69.2 81.1 79.0 58.2 60.5 .90 84 50 51 1.42 7.73
May .......................... 75.9 79.0 86.6 91.9 66.9 72.8 92 93 57 65 4.21 4.87
June .......................... 79.3 78.1 87.5 88.0 74.3 69.1 96 95 69 56 6.16 7.56
July ..................... 83.6 80.2 93.5 a 88.8 75.5 74.4 99 93 71 68 3.37 11.23
August .................. 84.0 80.9 90.1 90.0 78.5 71.9 95 94 73 71 5.96 5.45
September .............. 78.8 80.9 86.8 86.3 72.6 73.2 92 93 65 69 1.26 8.57
October .................. 71.2 74.1 83.3 83.4 66.1 67.1 89 89 54 60 2.95 1.54
November ................ 62.8 61.5 71.9 72.2 54.8 51.9 85 83 40 37 4.50 2.05
December ................. 67.1 61.8 73.5 73.7 55.4 53.0 82 81 35 38 0.12 .64
10 Florida Agricultural Experiment Station
which observations were made. For comparisons of the duration
of the various stages in the adult life with temperature records,
see Table 2. During the summer months there is little variation
in the length of these stages; but during the colder months there
is considerable variation, as is brought out by comparing Tables
1 and 2.
The oviposition period ranges from 3 to 7 days and averages
about 5 days for the warmer months. After egg laying is com-
pleted, the female moths soon die, living less than a day after
completing the oviposition period. The female moth lives from
4 to 10 days and egg laying is usually heaviest during the first
S three days of the oviposition period. As many as 627 eggs have
been obtained on the first day. The largest total number of eggs
laid by a single female was 1,321. Several individuals laid from
900 to 1,100 eggs, while the average number of eggs per female
as shown in Table 3 is considerably lower. The adult male moth
usually outlives the female by several days.
TABLE 3.-AVERAGE NUMBER OF EGGS AND EGG MASSES PER FEMALE
Laphygma exigua HBN. AT LEESBURG, FLORIDA DURING 1932 AND 1933.
SAverage Number I[Average Number
Number of Eggs Per Egg Masses
Month Females Female Per Female
1932 I 1933 Ij 1932 I 1933 JI 1932 1 1933
A pril ................................ ............ 3 ................ 876.6 ............. 15.0
M ay ....................................... .........590.2 ............ 12.0
June .................................. 8 476.0 666.2 9.3 11.7
July .................................. 20 11 429.4 762.8 12.2 19.0
August ............................ 16 3 543.2 339.7 12.0 12.0
Septem ber ...................... 7 ............ 599.7 .............. .. ............ ..
DURATION OF EGG STAGE
The duration of the egg stage (Fig. 2) is very markedly
influenced by the temperature. During the summer months the
eggs will hatch in 2-to-3-days, but a variable length of time is
required for hatching during the winter months. The longest
time recorded for the incubation period was four days during
the latter part of October.
Numerous experiments were conducted to determine the dura-
tion of the egg stage. This information is tabulated by months
in Table 4. The eggs were kept, in all cases, in test tubes plugged
The Asparagus Fern Caterpillar 11
with cotton in an open insectary. In no case did the eggs re-
quire moisture additional to that of the atmosphere. The Florida
climate supplies sufficient moisture for the development of all
stages of the asparagus caterpillar in the insectary and fernery.
Since all of the eggs kept in the test tubes plugged with cotton
hatched, it may be concluded that there is little or no mortality
of the unparasitized eggs. A few unmated females deposited
a small number of eggs during the latter part of their lives but
none of these eggs hatched.
TABLE 4.-DURATION OF THE EGG STAGE OF THE ASPARAGUS CATERPILLAR,
OBSERVED AT LEESBURG, FLORIDA DURING 1932 AND 1933.
I Average Duration
Number of Egg of Egg Stage
Month Masses Usessd in Days
_1932 1933 |I 1932 | 1933
M ay ................................... .. ....-....... .... 105 .................... 2.5
June ...................................... 55 82 1.6 2.5
July ...................................... 176 170 2.1 2.5
August .................................. 197 35 2.2 2.0
September ............................ 50 1 2.6 2.0
October ................................ 14 167 4.0 3.4
N ovem ber ............................-.................. 27 ...............*
Eggs failed to hatch on account of cold weather.
It will be noted from Table 4 that 27 egg masses or 716 eggs
failed to hatch. These eggs were laid between November 3 and
15, 1933. During the 13-day period Nov. 3 to 15 inclusive the
average temperature was 66.70 F. and on 10 of these days the
minimum temperature was below 500 F. with 430 F. as a mini-
mum for three of these days. Apparently these temperatures
are low enough to prevent hatching. However, eggs laid later
in a fernery near the laboratory hatched, for larvae were ob-
served in this fernery during the first part of December.
The newly hatched larva (Fig. 3) is only 25 inch long
with a comparatively large black head and light green body
covered with small tufts of spines. Hatching is accomplished
by chewing a hole in the top of the egg shell through which
the caterpillar emerges. After emerging the larva finishes eat-
12 Florida Agricultural Experiment Station
ing the egg shell. All of the eggs in a mass hatch at approxi-
mately the same time, and the larvae remain together for a few
hours feeding on the near-by foliage, and then they begin to
scatter to different parts of the plant.
TABLE 5.-DURATION OF LARVAL STAGE OF THE ASPARAGUS CATERPILLAR
OBSERVED AT LEESBURG, FLORIDA DURING 1932 AND 1933.
Number of Duration
Month Larvae Hatching Pupation Larval
Used Dates Dates Instars,
_______ ______ _____ DgDays
193219331932 1 1933 1 1932 11933 |3 1932 | 1933
M ay... ................ ...... 14 ........... 4-20 ................5/17-6/5 .......... 15.0
June................ 8 17 14 15-20 24-28 6/27-7/1 11.5 11.7
July................ 12 8 1-14 9 14-31 21-24 12.5 13.2
August.......... 1 8 10 2-30 22 8/19-9/14 12.0 12.0
September................ 7 ............ 26 ............---------- 10/5-7 ......... 9.7
October...................... 3 ............ 21 ................ 11/3-4 ........ 13.3
November.................. 7 ............ 2 ................ 12/7-12 .......... 37.6
There are five instars or stages through which the larvae pass.
Each molt is preceded by a pre-molting period, the length of
which depends upon the temperature. During the summer
months each stage requires about 2 days which includes 6 to 10
hours for the pre-molting period. The exact length of this pre-
molting period was not determined. Only the total length of
the larval stage is given in Table 5. Records included in Table 5
are for those larvae only which completed the larval stage, al-
though many more larvae were reared to the third or fourth
During June, July, August and September when the mean
temperature ranged from 78.1 F. to 80.90 F. the larval stage
was completed in some instances in 10 days, although the aver-
age ranges between 11.5 and 13.2 days for these months. During
September, 1933 three individuals completed the larval stage in
9 days. During November with an average temperature of
61.50 F. the larval stage required 37.6 days. The cool weather
of November prevented the hatching of eggs and most of the
pupae died so that a generation of larvae was not reared during
December. A single adult male emerged November 27 and died
TABLE 6.-DURATION OF THE PUPAL STAGE OF THE ASPARAGUS CATERPILLAR AS OBSERVED AT LEESBURG, FLORIDA DURING
THE YEARS 1932 AND 1933.
Average Duration Number of Males Ratio of -
Month Pupation Dates Dates of Adult of Pupal Stage and Females Males to
Emergence in Days d I ? [ Females
1932 1933 1 1932 1933 1932 | 1933 1932 1933 |
May .........................-.......- .................. 5/17-20 ............. 5/23-27 ............... 7.0 .... ....... 3 4 1-1.3
June ...........................---.... 6/26-7/1 6/3-6/30 7/1-7/2 6/11-7/8 6.0 6.9 2 5 11 10 1-1.1
July ...........................---- 7/12-7/31 7/1-23 7/19-8/7 7/8-30 6.3 7.2 3 7 6 6 1-1.4
August ............ ............--- 8/2 8/19-27 8/9 8/26-9/2 7.0 7.4 0 1 3 4 1-1.6
Septem ber ................- ..................... 9/14 .................. 9/20 .................. 6.0 ........ .... 0 1 1-0.3
October .......... ......-- 10/10-11 10/5-7 10/19 10/16-18 8.7 11.0 4 2 6 1 ................
November .................. ... 11/3 .................. 11/27 .................. 24.0 ...... ...... 1 0
Total........... ..... .................. ..... ............ 9 15 30 26 1-1.0
14 Florida Agricultural Experiment Station
The full grown caterpillar (Fig. 4) measures one and one-half
inches in length and varies in color from a light green to black.
The light green individuals show no distinct stripes nor do the
black individuals. Some individuals have three distinct light
colored stripes running the full length of the body, one at the
middle of the back and one at each side. The caterpillars vary
so in color that some growers contend that they are separate
species. Light green and black individuals have been reared
from the same egg mass, though the dark caterpillars are more
numerous in the early spring, late fall and winter and the green
caterpillars are more numerous during the summer months.
This indicates that there is a close correlation between low tem-
perature and dark pigmentation and between high temperature
and light pigmentation.
The full grown larvae dig into the soil, form a cell about
themselves and transform to the pupal stage. All of the pupae
observed in the insectary were in a perpendicular position with
the head up.
Of the individuals completing the pupal stage (Fig. 5) there
were slightly more females than males. Luginbill (6) reports
that female pupae of the fall army worm completed the pupal
stage in a slightly shorter time than the male pupae. For the
asparagus caterpillar both sexes completed the pupal stage in
the same average time. Table 6 gives the duration of the pupal
stage for each month during which observations were made.
The length of the pupal stage, like the earlier stages of the
asparagus caterpillar, is greatly influenced by the prevailing-
temperature. When the average temperature is between 78
and 810 F. the pupal stage is completed in fromf-te-8days-,
averaging about 7 days. At lower average temperatures the
length of the pupal stage is greatly increased (see Table 6).
NUMBER OF GENERATIONS AND LENGTH OF LIFE CYCLE
For the summer months the adult pre-oviposition period aver-
ages 2.6 days, the egg stage 2.2 days, the larval stage 12.5 days,
and the pupal stage 6.7 days, the sum of which totals 24 days
for the length of the life cycle. From June 14 to October 10,
1932 six compete generations were reared. From May 1 to
September 20, 1933 six complete generations were reared.
The larvae begin to appear in numbers during April or May
and become very abundant during June. After June 1 no dis-
The Asparagus Fern Caterpillar 15
tinct generations can be distinguished in the fernery. Sometimes
all stages of the asparagus caterpillar will be found in the fern-
ery at the same time. Thus, there are many more than six
broods of the larvae to be combatted during a season.
For this reason no definite time can be specified for applying
control measures. The need for control measures will vary from
fernery to fernery, wherefore each grower must maintain a
constant vigilance to determine the proper time for applying
insecticides. The proper time is as soon as possible after the
eggs hatch. Some growers contend that the very young cater-
pillars are not large enough to eat sufficient foliage to get a
lethal dose of poison and advocate waiting for three days after
hatching. Those growers who practice waiting for three days
usually suffer a heavy loss. With favorable weather conditions
almost complete control of the larvae within eight hours after
applying the insecticide has been obtained. The insecticide was,
of course, applied to the asparagus foliage when the asparagus
caterpillars were only a few hours old.
As an aid to determining the proper time, watch the whitish
egg masses on the under side of the young foliage. Mark these
egg masses and note the time of hatching. If weather conditions
are not favorable for applying the insecticide make an applica-
tion as soon as weather conditions permit. If this is neglected
there is sure to be trouble later.
During the summer months of 1932 conditions for the develop-
ment of the natural enemies of the asparagus caterpillar were
exceptionally favorable. During these months eight parasites,
four secondary parasites (parasites preying upon the first para-
site and therefore detrimental to the interest of the grower) and
two predators were reared from material collected in the fern-
eries. In 1933 conditions in the same ferneries were not favor-
able, only a few individuals of two parasites being collected.
Of the eight parasites Chelonus texanus Cress. was the most
abundant and effective in destroying the larvae of the asparagus
caterpillar. No common names for these parasites are known
to the author, so scientific names must be used. Next in im-
portance were Meteorus autographae Mues. and Apanteles mar-
giniventris (Cress.), these two being found in equal abundance.
Euplectrus platyhypenae How. was observed on several occasions
in the ferneries at Leesburg and Pierson, but it was never abund-
16 Florida Agricultural Experiment Station
ant. At Boynton, however, this parasite was encouraged and
it became very abundant, parasitizing the semitropical army
worm (Prodenia sunia Gn.). Single specimens of Hyposoter
interjectus Gahan, Zele melleus (Cress.), Gonia crassicornis
Reinh., and Eucelatoria rubentis Coq. were reared. The four
secondary parasites reared were Spilochalsis hirtifemora (Ash.),
Spilochalsis albifrons Walsh, Catolaccus aeneoviridis (Gir.), and
Mesochorus sp. Two predators very abundant in the ferneries
were active in destroying the asparagus caterpillar. These were
Podisus maculiventris Say and Polistes fuscatus var. rubiginosus
Chelonus texanus adults lay their eggs in the eggs of the as-
paragus caterpillar, and the full grown parasite larva emerges
from the third or fourth stage host larva. The other parasites
attack various stages of the asparagus caterpillar. One of the
principal reasons for the parasites never becoming abundant is
that control measures are directed at host larvae, thus destroying
the immature parasites with the host asparagus caterpillar.
In addition to the insect parasites of the asparagus caterpillar
there is a fungus disease Spicaria prasina (Maubl.) Saw. which
destroys large numbers of the asparagus caterpillar and a bac-
terial disease is very destructive during the months of Septem-
ber, October and November.
The vertebrate parasites of the asparagus caterpillar have
not been studied although a lizard Cnemidophorus sexlineatis
(Linn.), "the race runner", is very abundant in the ferneries
and a toad, Bufo quercicus Holb., also is abundant. These un-
doubtedly destroy large numbers of the larvae.
HYMENOPTEROUS PARASITES AND SECONDARY PARASITES
Hyposoter interjectus Gahan.: Vickery (10) does not list this
insect as a parasite of the fall army worm in Texas nor does
Luginbill (6) give it as a parasite of this insect in the Southeast.
Only one specimen was reared at Leesburg, thus it may be only
an occasional parasite of the Laphygma. The pupa was collected
in the insectary from a cage containing a large number of as-
paragus caterpillars on June 5, 1932. The adult emerged on
June 10, 1932.
Mesochorus sp.: Three pupal cases of this secondary parasite
of the asparagus caterpillar were collected in the fernery on
August 15, 1932 and the adults emerged August 22, 1932. This
The Asparagus Fern Caterpillar 17
secondary parasite is given by Luginbill as a parasite of Meteorus
laphygmae. Luginbill also states that three individuals were
reared from 295 Meteorus laphygmae cocoons, indicating that
this is an insignificant secondary parasite.
Chelonus texanus Cress.: Numerous attempts were made to
rear this parasite in captivity. Vickery (10) has found that
it is necessary to have the host larva go into the ground pre-
maturely and construct a cell known as the death cell. Under
the conditions prevailing in the insectary the writer was unable
to get the host larva to construct the necessary death cell. Num-
bers of the Chelonus larvae emerged from the host but because
of the absence of the cell they soon died. As has already been
indicated, this insect was very abundant in the fernery and
frequently emerged from host larvae collected in the fernery.
Vickery states that 33 percent of all the fall army worms col-
lected at Brownsville, Texas were parasitized by this insect.
Since large numbers of the host were collected this probably
represents the actual status of this parasite in the vicinity of
The adult female oviposits directly in the eggs of the aspara-
gus caterpillar. Females were placed in test tubes containing
eggs of the asparagus caterpillar and they usually began ovi-
positing immediately. The female parasite approaches the egg
mass and places the antennae on an egg, she then places the
ovipositor over an egg retaining it there for a few seconds. The
female will work back and forth over the egg mass selecting
eggs at random, the antennae vibrating vigorously all of the time.
The host egg develops normally, hatching in the same length
of time as unparasitized eggs. The host larva also develops
normally to the third or fourth instar. Parasite larvae reared
in the insectary at Leesburg emerged from the host during the
third instar. The host larva attempted to pupate 11 to 14 days
after the parasite egg was laid. The Chelonus larva emerged
from the caterpillar on the 12th to the 15th day after oviposition
by the female. Vickery gives the time elapsing from oviposition
to the time of cocoon formation as 11 days in August and 22
days in October. At Columbia, South Carolina the time elapsing
between the hatching of the fall army worm larva to pupation
of the Chelonus was 12 to 14 days.
Luginbill (6) states that the parasite passes the winter as a
pupa in the cocoon. Adult Chelonus feed at the nectaries of
18 Florida Agricultural Experiment Station
cotton and a number of other plants. Data on the number of
generations produced during a season were not obtained.
Apanteles marginiventris (Cress.) is another parasite abund-
ant in the ferneries at Leesburg. The female Apanteles lays
her eggs in the first instar larvae of the host usually before they
disperse. Oviposition is accomplished very quickly, the female
thrusting her ovipositor into the larva and withdrawing it im-
According to Vickery the length of time from oviposition to
the emergence of the full grown parasite larva varies consider-
ably even in groups of parasite eggs laid at the same time. In
June the time ranged from seven to 11 days; in October from
seven to 13 days, and in November from 10 to 14 days. A single
parasite larva emerges from each parasitized asparagus cater-
pillar during the fourth instar. Adults emerged from cocoons
collected in the fernery after 2 to 6 days, the average being 3.3
days. The shortest pupal state for this parasite in Texas was
Meteorus autographae Mues.: This parasite was found in the
ferneries in about the same numbers as Apanteles marginiven-
tris. Observations on the oviposition and length of the larval
stage have not been made. Numbers of adults, however, were
reared from parasitized larvae brought into the insectary. The
adult parasite emerged from cocoons formed in the insectary
after six days. The adult female usually lays her eggs in second
or third instar host larvae. This parasite may reproduce with-
out mating but the progeny are always males when the female
is not fertilized.
Zele melleus (Cress.) : A single specimen of this parasite was
reared from a parasitized larva of the asparagus caterpillar by
C. C. Goff at Leesburg in June, 1931. Various entomologists
of the U. S. Bureau of Entomology have reared this parasite in
small numbers from the fall army worm. Vickery reared only
three adult Zele melleus from 16,000 fall army worm larvae at
Two secondary parasites belonging to this family were reared,
both from Apanteles marginiventris (Cress.).
Spilochalcis hirtifemora (Ashm.): Two individuals of this
secondary parasite were reared from cocoons of Apanteles mar-
giniventris collected in the fernery. The adults emerged 10 days
after the cocoons were collected.
The Asparagus Fern Caterpillar 19
Spilochalcis albifrons Walsh: A single specimen of this species
was reared from cocoons of Apanteles marginiventris collected
in the fernery. The adult S. albifrons emerged seven days after
the cocoons were collected. The adults of this and the preceding
species were reared during August.
Catolaccus aeneoviridis (Gir.) : Several adults of this small
black secondary parasite were reared from cocoons of Apanteles
marginiventris collected in the fernery during July and August.
One adult C. aeneoviridis emerged 2 days, one 3 days, one six
days and several 10 days after the cocoons of A. marginiventris
were collected in the fernery.
All of the secondary parasites were reared in such small
numbers that they appeared not to reduce the primary parasites
to an appreciable extent.
Euplectrus platyhypenae How.: Although this parasite was
not collected in large numbers at Leesburg it is easily reared,
and being a gregarious external parasite all stages of the life
cycle can be observed with little difficulty. Probably the sys-
tematic application of arsenate of lead reduces the numbers of
this parasite, as the female prefers to oviposit on the third or
fourth stage host larvae. This parasite has been reported as
parasitizing a number of noctuid species. The list includes 13
species of Noctuidae. At Leesburg it was reared from the as-
paragus caterpillar and was observed on Prodenia sunia Gn. at
At one time during the life history studies, first and second
stage host larvae were all that were available for the female
parasites to oviposit on. For 10 days these small larvae were
offered to the parasites but no eggs were deposited until third
and fourth stage host larvae were made available. The eggs
are laid in groups ranging from three to 30 in number usually
on the thoracic or first three abdominal segments. Eggs placed
on the posterior abdominal segments are frequently knocked
off by the host larva after the eggs hatch.
During the months of June to September, 1932, inclusive,
with an average temperature of 81.40 F. the average length of
the egg stage was 2.28 days. During this time 9 generations
were reared. From the middle of November to the latter part
of December while the average temperature was 63.20 F. the egg
20 Florida Agricultural Experiment Station
stage lasted 8 days. The average length of the larval stage for
the first 9 generations was 3.53 days. The 12th generation
larvae (reared during December) required 9.75 days for de-
Parasitized asparagus caterpillars did not molt after the
parasite eggs were laid. Frequently the female parasites refused
to lay eggs on larvae almost ready to molt, but waited until the
skin had been shed. The host larvae feed normally throughout
the period of the parasite larval development. When the para-
site larvae become full grown they move around to the ventral
surface of the host and tie it down with silk threads. A few
threads of silk are spun about the parasite and the pupa is
formed beneath the dead host larva. In Florida the parasites
continue development during the winter although the life pro-
cesses are slowed down during cool periods.
Polistes fuscatus var. rubiginosus Lep.: Large numbers of
these wasps were present in the ferneries during the entire
summer of 1932. C. C. Goff observed the wasp capturing the
larva and preparing it for transportation back to the nest. Mr.
Goff's description of the process follows: "After following a
wasp about for some time I saw her make a dart for a large
larva but for some reason she missed her prey. Several times
larvae escaped by falling to the ground as the wasp approached.
Finally the wasp was successful in capturing a larva probably
in the fifth instar. As far as I was able to observe the wasp
did not sting the larva but immediately began to chew at it vig-
orously, holding the larva with her front feet. In approximately
five minutes the wasp had peeled the skin from the larva and
then flew away with the viscera."
Podisus maculiventris Say: This predacious bug was very
abundant in the ferneries at Leesburg from the latter part of
June to the latter part of August, 1932. The adult has a long
life and is a voracious feeder, one adult captured on June 26
lived to September 4, during which time 122 asparagus cater-
pillars were consumed. The stink bug approaches the larva
cautiously with the beak outstretched, and immediately presses
the beak into the larval skin. By the time the larva begins to
wiggle in an attempt to escape, the stink bug has secured suffi-
The Asparagus Fern Caterpillar 21
cient hold to make any amount of wiggling unsuccessful. No
larvae were observed to escape.
The eggs are placed in masses on the asparagus sprays or
other convenient supports. A female captured in the fernery
on August 5 had laid a total of 871 eggs by September 23. Two
reared females laid 238 and 768 eggs, respectively. The average
length of the egg stage during September 1932 was 5.08 days
with an average temperature of 78.80 F. during the same time.
The newly hatched nymph has a black head and thorax and
red abdomen with black marginal spots on each segment and
four transverse black spots at the center of the dorsal surface.
The nymphs from an egg mass stay together for the first two
or three days, moving about in a body in close formation. Al-
though very young nymphs feed on the tender plant shoots they
do not appear to injure the asparagus plants, and after their
first few meals they begin feeding on the smaller larvae. The
nymphs molt five times and require 20 to 23 days during the
latter part of August and the first part of September to complete
Three generations of this predator were reared from August
to December 20 when the supply of asparagus caterpillars gave
out. This species probably passes the winter in the adult stage.
In addition to the asparagus caterpillar it feeds upon a number
of other insect larvae.
Gonia crassicornis Reinh.: A single specimen of this dipterous
parasite was taken from a rearing cage on July 1, 1932. Van
Dine (9) also reared this parasitic fly from a fall army worm
larva in Porto Rico in 1912. It appears to be a rare parasite of
the asparagus caterpillar.
Eucelatoria rubentis Coq. A single specimen was reared by
C. C. Goff in 1931. The larval parasite emerged from the host
larva on August 27 and the adult fly emerged on September 4,
1931. This also appears to be a rare parasite as it is mentioned
by neither Luginbill nor Vickery.
The fungus Spicaria prasina (Maubl.) Saw. during wet
weather destroys enormous numbers of asparagus caterpillars,
attacking the larvae in all stages. This fungus has been ob-
served to destroy entire infestations of the caterpillar when the
22 Florida Agricultural Experiment Station
optimum weather conditions prevailed for its development.
The infected larva becomes stiff and is covered with a white
mass of mycelia soon after death. These mycelia bear green
spores which after a short time give the dead larva a green
A bacterium, not yet identified, was found destroying many
of the larvae in rearing cages in the insectary. Only a few
caterpillars that appeared to have been killed by this bacterium
have been found in ferneries. Some caterpillars were destroyed
during all of the summer months. However, it became very
difficult to rear larvae to maturity during September and Octo-
ber on account of attacks of this bacterium. There seems to be
some relationship between the lower temperatures of these
months and increased mortality of the larvae. Whether this
phenomenon is due to the fact that these lower temperatures are
more favorable to the development of the bacterium or that the
resistance of the caterpillars is decreased by the lower tempera-
tures has not been determined.
The practice of planting Asparagus plumosus plants about
six by 10 inches apart and the low, compact growth of the plants
makes dusting the most desirable and economical means of con-
trolling the asparagus caterpillar. Many fern growers plant
Asparagus plumosus in beds three feet wide, leaving 12 inch
paths between, while others plant the entire fernery, leaving
no paths. Under these conditions the handling of spray hose
in such a way as to prevent injury to the plants is quite an item
in the cost of applying a spray. The dust, if properly applied,
will give a better coverage of the plants and can be put on in
approximately one-eighth the time of that required for spraying.
However, liquid sprays containing pyrethrum and rotenone
compounds in varying proportions were tested. The degree of
control obtained with these materials was not satisfactory.
The fluosilicate compounds used in similar tests were also
unsatisfactory, all giving a poor control when compared with
arsenate of lead. The dusts containing sodium and barium fluo-
silicate severely injured the plants.
In Table 7 the yield per acre of marketable sprays is calculated
from the results of a typical series of plot tests. This table
The Asparagus Fern Caterpillar 23
shows clearly that undiluted arsenate of lead was the most ef-
fective of these materials. No injury to the plants could be
attributed to the use of this dust.
TABLE 7.-COMPARATIVE EFFECTS OF DIFFERENT INSECTICIDES UPON THE
CONTROL OF THE ASPARAGUS CATERPILLAR AS DETERMINED BY THE YIELD
OF MARKETABLE SPRAYS PER ACRE.
Material Used Marketable
Untreated check ...........-.... ................... 13,452
Arsenate of lead undiluted........... .... .. ....... ........ ....... 40,890
Rotenone (5% on label).....- .......- ....... ................ 20,392
Arsenate of lead 50%, lime 50%........................... .... ....... 28,826
Calcium arsenate 50%, lime 50%..............--............ ...... 28,719
Calcium arsenate undiluted........... ..- .... .........._.......- 25,516
Synthetic Cryolite 10%, Kaolin 90% ..........-........... 13,345
Pyrethrum "A" dust ............ ............ ..... ....... 24,876
Magnesium arsenate 20%c, Kaolin 80'/c%............ -........ 24,449
Growers have been using arsenate of lead as a control measure
for a number of years. Still some of them complain that they
do not get control. According to the author's observations the
reasons for failure to obtain control are as follows:
1. Failure to dust at the proper time.
A. Ignorance of the life history and habits of the asparagus
B. Excuses of being too busy with other thinks.
C. Failure to keep up with what is going on in their
2. Failure to apply the dust properly.
A. Relying upon cheap labor.
B. Insufficient attention to labor.
3. Weather conditions.
As has been explained on previous pages the growers must
familiarize themselves with the life history and habits of the
asparagus caterpillar in order to apply control measures intel-
ligently. When the egg masses are observed in numbers there
are sure to be larvae in about two days. The dust should be
applied immediately on the appearance of the larvae. It is best
24 Florida Agricultural Experiment Station
to apply it as early as possible in the morning. At this time
of the day weather conditions are most favorable. There is
usually some dew on the plants, little or no wind, and one may
usually count on a period of about 8 hours before a rain. If the
dust is applied to the newly hatched larvae, control can be
obtained in approximately 8 hours.
If an excellent crop of asparagus ferns is to be grown, enough
labor should be available to take care of all phases of production
including culture and harvesting. Sometimes growers become
engrossed in harvesting and fail to think, in time, of the crop
Although some growers know about the life cycle of the
asparagus caterpillar and have sufficient labor available, they
sometimes for one reason or another fail to recognize the need
for dusting until after considerable damage has been done.
Most of the dusting in the Leesburg area is done by hired
labor with a Savage type duster. If the laborer takes short
steps, turns the duster handle at the proper speed, and swings
the nozzle of the duster over a -wide enough area an excellent
coverage with the dust can be obtained. Many laborers walk
too rapidly when dusting and a crooked trail of the duster can
be followed through the fernery.
Another point is the height of the duster nozzle above the
tops of the plants. The duster nozzle should be held so that the
dust cloud is placed from six to 12 inches above the tops of the
plants. If this is done a uniform coat of dust will settle on all
parts of the plants.
While the dust is being applied a responsible person should
constantly watch the application of the dust as the labor used
in ferneries usually cannot be relied upon to do as instructed
unless constantly reminded to do so.
It sometimes happens during the summer that for three or
four days there will be some rainfall during all hours of the day.
Under such circumstances it will be impossible to obtain control.
It is advisable to watch the weather forecasts and see to it that
there are no larvae present in the fernery at the commencement
of a rainy period.
Although there has been some objection to the use of arsenate
of lead in large quantities year after year, on the grounds that
so much arsenate of lead in the soil is injurious to the plants,
this is the only material available at the present time which can
be relied upon to give control of the asparagus caterpillar. If
The Asparagus Fern Caterpillar 25
the proper precautions are taken and arsenate of lead is applied
at the right time little damage will be inflicted by the asparagus
The asparagus caterpillar is the most abundant of the night
flying moths found in the ferneries in Florida. This insect has
been reported to feed on 18 plants other than asparagus plumosus,
but in Florida it has rarely been found outside of ferneries.
There is no definite record of its first appearance in the ferneries
but it has been in the state for a number of years.
The damage inflicted is of two types: (1) the young larvae
feeding on the tender buds, and (2) the older larvae feeding on
the more advanced growth.
Eggs are laid on the underside of the sprays in masses. These
masses are usually covered with scales from the female moth's
body. The eggs hatch in two to three days during the summer.
The larvae molt five times and require nine to 15 days (during
the summer months) to complete this stage. The mature larvae
form a pupal cell a short distance below the soil surface and
remain in this cell for six to 11 days during the months from
May to October. The length of these stages is increased con-
siderably during the winter months.
A number of primary and secondary insect parasites of the
asparagus caterpillar have been collected and reared. Two of
these, Chelonus texanus Cress. and Euplectrus platyhypenae
How., are of considerable aid in controlling this pest. The
fungus, Spicaria prasina (Maubl.) Saw., is instrumental in de-
stroying large numbers of the larvae. An unidentified bacterium
also is considered of some slight control value.
The best artificial control which has been developed for the
asparagus caterpillar is a timely dusting of undiluted arsenate
-26 Florida Agricultural Experiment Station
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