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^3 -v- The Looper (Plusiinae) Situation In the Everglades
and Adjacent Areas: A Report of Progress /
G. Genung HUME LIBRARY
and
ScP 11 1972
M. J. Janes
I.F.A.S. Univ. of Florida
Since the mid 1950's, the looper problem on be e
increasingly difficult, due in part to development of resistance to various
chlorinated hydrocarbon and organic phosphate insecticides. The declining
effectiveness of insecticides for cabbage looper control was pointed out by
Genung (3) in 1957, who presented several seasons data with three insecticides
to show the development of this factor. While a similar continuity in substan-
tiating data are not available for the soybean looper and the bean leaf skeleto-
nizer, it is apparent from many observations that the same situation developed
almost concurrently in regard to them. This fact has surely contributed to
their increased economic importance -- the same materials that previously
controlled the cabbage looper so effectively also kept other species under
suppression. More recently the persistence of the problem
of resistance in cabbage looper was shown by Greene et al (6).
Because of recognition of the greater importance of certain Plusiinae
species in addition to the cabbage looper and because of difficulties in
obtaining the necessary degree of control, a report of research results on the
present status of these species was considered desirable.
1/ Research aided in part by grants-in-aid from Shell Chemical Co., Niagara
Chemical Division FMC Corp,, Amdal: Co. and Union Carbide Corp.
Everplades Experiment Station Mineo Report EES70-12
"ay 1970
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The Changing Status
For many years, loopers of the noctuid (Phalaenid) sub-family Plusiinae
observed on vegetable crops in the Everglades and elsewhere in Florida were
generally reported as "cabbage looper", except when on celery in which case they
were almost invariably termed "celery looper". The more recent reports of
Hensley'et-al. (8) and Canerday and Arant (1) indicate that a tendency to lump
tho- loopecr complex under cabbage looper also existed in Louisiana and Alabama.
A perusal of the cooperative Exonomic Insect Report for the 1950's and early
1960's indicates that the same trend was probably national in scope. It
is evident that there has been much erroneous reporting in respect to the
Plusiinae.
What then has led to the recognition of the fact in recent years that
complexes are often involved where formerly a single species of that complex was
considered the major cause of crop injury? Three factors have mainly contributed
to this recognition, namely: 1) more careful identification resulting in
elimination of snap judgment, 2) the development of a considerable degree of
insecticidal resistance and 3) changes in insecticidal control programs due
to certain pesticide use restrictions, In some areas, agronomic changes are
believed to be involved (8) but such changes are too insignificant to be
considered valid for the Everglades area.
The Plusiinae Comnlex
A survey initiated several years ago to determine the composition of this
fauna and the economic status of its components received impetus and encourage-
ment through a cabbage looper latitude survey, with the USDA and University of
Florida cooperating. The cabbage looper latitude survey will determine
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feasibly of an eradication program by use of sterilization techniques. Eight
looper species have been collected at the Everglades Station under a routine
adult trapping program on a year round (weekly) basis. A light trap equipped
with a 15 W vertical BL lamp was used to attract moths into a walk in type
cage where they could be carefully collected for identification. A sex pheromone
wao ,od as an added lure for the cabbage looper. The species were then deter-
mined by use of Habecks Annotated Key to the Plusiinae Moths of Florida (7).
The species and trapping data are given in Table 1.
In addition, collections of late instar larvae and pupae were made from
various crops and other plants for rearing to the adult stage for species
identification. Results of these hearings for recent years are given in Table
2. The present economic status of the various species is discussed in the
following paragraphs.
Cabbage looper Trichoplusia ni (Hubner): This looper remains the most
important single species in the area. It is almost the only looper presently
attacking cabbage and other crucifers. In addition, it has caused severe
injury to celery, lettuce, beans, tomatoes, southern peas, and floral crops.
It has also attacked corn and.may eventually acquire a taste for this crop,
(Table 2).
Soybean looper Pseudoplusia includes (Walker): The soybean looper has
become a major pest of beans. It also attacks southern peas, celery, tomatoes,
lettuce and floral crops. During the 1969 season, it occurred widely and in
large numbers on sweet corn and must be regarded as a potential pest of that
crop (Janes and Greene, 9).
A bean leaf skeletonizer Autoplusia egena (Guenee): During the late
1950's and early 1960's, this looper caused heavy injury to snap beans and
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pole beans (Genung, 4). It occurred in very light numbers on soybeans and
southern peas. While numbers have been low in recent years it will probably
have to be reckoned with again in the normal fluctuation of species.
Autographa biloba (Stephens): While light trap catches indicate that this
is a fairly common species we have reared it only one time from any crop (beans).
It is reported to attack "vegetable crops". Since it is a rather common species
it would not be surprising if this looper became economicly important.
Argyrogramma verucca (Fabricius) This species was only reared from beans
but it is fairly frequent in light trap catches and over a considerable period
of the crop season.
Rachiplusia ou (Guenee), Argyrogramma basigera (Walker) and Trichoplusia
oxyogramma (Geyer) have not been reared from crops or other plants in the Ever-
glades or vicinity. R. ou was found in numbers attacking clover in Louisiana
and Alabama (8), (1), and once on cotton in Louisiana (8).
It will be noted that the celery looper is not a component of the complex
in the Everglades from either trapped adults or immatures reared to adults from
crops. From 90 to 98 percent of loopers on celery in the Everglades have been
cabbage loopers. Examination of specimens dating back over twenty years shows
not a single example of the celery looper taken or reared from the Everglades
area. In fact it is only recently that a known specimen of the celery looper
was taken anywhere in Florida. According to C. P. Kemball (personal conversation:
there was some consideration about removing it from the list of Florida species
prior to that occasion. This is despite the fact that the celery looper has been
carried in the Florida literature for over 50 years (Watson, 11; Watson and
Tissot, 12; Wilson and Hayslip, 13; and Genung, 2). Kimball (10) had probably
included the species in his book on the basis of some of tleso and other reports.
Table 1. Numbers of weeks of occurrence and total numbers of adult Plusiinae trapped January
December 12, 1969. 1/
Species
Trichoplusia ni (Hubner)
Pseudoplusia includes (Walker)
Trichoplusia oxyogramma (Geyer)
Rachiplusia ou (Guenee)
Autographa biloba (Stephens)
Argyrogramma basipera (Walker)
Argyrogramma verucca (Fab)
Autoplusia egena (Guenee)
STrap run one day per week.
No. Weeks Found
28
32
9
No. Individuals for Year
489
153
Occurrence dates for year
1st Peak last
47T 5713 1279
3/11 4/29 2/9
5/27 6/10 8/12
4/8
3/11
4/22
11/4
4/29
11/25
Table 2. Numbers of various Plusiinae reared
No. ,/ No. No.
Host larvae- T. ni P. incl.
Celery 305 163 11
Beans 243 35 84
Caobage 283 234 1
Lettuce 10 7 3
Collards 85 31 0
Tomatoes 28 20 8
Corn 100 5 33
Galinsoga 20 12 4
Anaranthus 38 18 6
Ci. npodium 24 12 4
Brassicz (wild) 1 1 0
Petunia 2 2 0
Calendula 6 3 1
Snap dragon 6 6 0
Total
1151
from various host plants 1967 1969.
No. No. No.
A. bilob. A. verucca A. egena
0 0 0
1 4 3
0 0 0
0 0 0
0 0 0
0 0 0
155
No. parasitized
diseased or missing
131
116
48
0
54
0
62
4
14
8
0
0
2
0
439
Th figures for y,
" The figures for celery,
beans and cabbage are totals of several samples collected over the three-year period.
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Biological Data
Cabbage looper: Incubation required five days in late March and early
April (less than 4 days in late May). Eggs are laid singly or a few together,
mainly on under-leaf surfaces. There were five larval ihstats requiring 4.12,
3.04, 2.64, 2.60 and 4.60 days, respectively, for a total larval mean of 17
days. The pupal stage averaged nearly iO days. Pupation occurs in a thin,
flimsy cocoon on the foliage. Adult females lived 13.71 days while males
averaged about four days longer. Thus, the entire life span from egg to death
of adult required about 45 to 50 days. Females laid from 148 to 1497 eggs and
averaged over 800. The productive life of females was 4 to 11 days. Diurnal
oviposition was not observed. Hatchability of eggs was nearly 98%.
Bean leaf skeletonizer: Oviposition habits are similar to the cabbage
looper. Four to five days are required for hatching. Larvae required a total
of 16 to 20 days and averaged about 17 days in May and June. Pupation occurs
in a cocoon in a folded leaf. The cocoon is thicker and tougher than that of
the cabbage looper. The pupal stage required 9 to 12 days. Observations were
not made on the number or duration of the individual larval instars.
Wild hosts: Several common weeds are attacked by cabbage looper and
soybean looper. Spiney amaranth, Amaranthus spinosus; fringed quickweed,
Galinsoga ciliata; and Lambs quarter,.Chenpodium album seem to be much relished
by the larvae. Oddly, wild crucifers are not important hosts, even of the
cabbage looper. They are rarely found on wild mustard. and have not been
observed on pepperweed, yellow.cress or other wild cruciferae.
Parasites: Cabbage loopers appear to be less frequently parasitized than
the soybean looper or bean leaf skeletonizer. Copidosoma truncatellum (Dalm) and
Meteorus autographae Muesebeck attack the cabbage looper occasionally. These
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wasps ard Apanteles autographae Muesebeck, frequently heavily parasitize soybean
looper and the skeletonizer, Genung (4).
Predators: Predators of these larvae include several species of the
stinkbug family including the Florida predacious bug Euthyrhynchus floridanus
(L.), Podisus mucronatus Uhler, P. maculiventris (Say), Alaecorrhynchus grandis
(Dallas), and the anchor bug Stiretrus anchorage (Fab). A reduviid bug Zelus
bilobus Say is also a frequent predator. Among beetles Calosoma sayi Dejean
and Caleida decora have been observed attacking cabbage looper. During the
nesting season, birds, particularly redwing blackbirds, boat-tailed grackes,
meadow larks and English sparrow, seek out infestations of these and other larvae.
The jumping spider Phiddipus audax (Hentz3 has also been noted feeding on various
Plusiinae, and several other spider species are suspected in this regard.
Diseases: Cabbage loopers, particularly at high temperature and humidity,
and under heavy population conditions are frequently almost wiped out by a
naturally occurring nuclear polyhedrosis virus disease. They are occasionally
killed by fungal diseases Spicaria rileyi and Entomopthora sp. It has seemed
that the soybean looper and bean leaf skeletonizer are more frequently attacked
by fungus disease than cabbage looper. They appear however not to be attacked
in this area by polyhedrosis virus and attempts to induce the disease in
laboratory populations from cabbage looper sources were completely unsuccessful.
Polyhedrosis virus of cabbage looper has been tried quite successfully in tests
at the Everglades Experiment Station for control of that species (5). It has
been used in combination with chemical insecticides without loss'of virulence
if used without prolonged delay. Although the disease occurs almost universally
in the environment, its grower use would require FDA approval.
Temperature: Nhere night temperatures fall below 600F there appears to be
reduced egg laying and under sustained cold rioAs P psIttl,->r .T...-Yi,
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to die out. After a cold winter infestations seem to start from a movement of
moths into the area. During warm winters rather heavy damage can be
caused by these larvae.
Experimental Control--
Tests have been conducted for many years in wbich loopers were either the
primary target or one of several target species or complexes. Tests reported
herein cover the past three seasons, only. The experiments were all randomized
complete block design, generally with four replications. Amounts of materials,
except as otherwise indicated are in pounds of active insecticide per acre,
and except as indicated were applied as sprays at rates of 100 gallons per
acre. Spray applications unless otherwise shown were made at weekly intervals.
The method of evaluation was used that seemed most applicable and was either
a count of larvae or a rating of damage and is indicated on each table. All
tests were conducted at the Everglades Experiment Station. Results of tests
are given in tables 3 8.
SExperimental materials are not recommended for grower use. Only materials
with use labels for a particular crop can be suggested for commerical
control.
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Table 3. Cabbage looper feeding ratings on King Cole Cabbage, Belle Glade,
1969 /.
Insecticide
Lbs A. I./A
UC-34096
Dupont 1642
Lannate
DDT
Toxaphene
Azodrin
Thuricide 90TS
GC-6506
Biotrol
Parathion
+
Endosulfan
Carbofuran
Parathion
+
Toxaphene
Naled
DDT
+
Azinphosmethyl
Mevinphos
Ciba C 9491
Polyhedrosis virus
Check
1.0
0.5
0.5
1.0
+
2.0
0.5
2 qts.
0.5
3.0
0.25
+
0.5
1.0
0.25
+
2.0
2.0
0.5
+
0.5
0.5
1.0
20 larvel units
1.55
1.52
1.62
ab 2
a
abc
2.12 abcde
1.70
1.85
2.20
1.78
abcd
abcd
cde
abcd
2.15 bcde
2.50 ef
2.10 abcde
2.15 bcde
2.32 def
2.20
2.80
5.00
4.22
4.22 g
Based on a 1 to 6 rating system where 1 = no feeding and 6 was riddled.
SMeans followed by the same number are not significantly different at the
5% level.
Rating
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Table 4. Number surviving cabbage'loopers per 10 head cabbage sample, Belle
Glade, Fall-I'inter 1968.
Insecticide Formulation Lbs A. I./A Mean no. Loopers/sample
Monitor E 0.5 0
Monitor E 0.75 0
Lannate WP 0.5 0
Thuricide Liq. 2 qts. 0
UC 34096 E 0.5 0.25
Azodrin E 0.75 0.25
Furadan Bait 1.5 0.25
Phosvel E 1.0 0.50
Galecron E 0.5 0.75
Check -- 6.00
Table 5. ContTrl of first and second
spr ng 196).
instar Plvsiinae larvae on lettuce,
Insecticide
Thuricide
Furadan
Parathion
Parathion
+
M. Parathion
Phosdrin
Thiodan
+
Pyrenone
Thiodan
M. Parathion
Furadan
Check
Formulation
90TS
751WP
4E
4E
4E
2E
2E
2 oz.
2E
4E
75 1WP
Lbs. A. I./A Number
2 quarts
1.5
0.5
0.33
0.17
1.0
2.0
0.5
1.0
feeding scars/head
.47
.60
.70
.70 a
.73 a
.77 a
.83 a
.97 a
.97 a
6.93 b
/ Means followed by the same letterare not significantly different at the
5% level.
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Table 6. Number of surviving cabbage looners nor head 1/ Snrinq 1969.
Insecticide
Dupont 1642
Fundal
Lannate
Monitor
Parathion
+
M. parathion
Biotrol
Azodrin
Naled
Parathion
+
Toxaphene
Biotrol
Mevinphos
Phosvel
Thuricide
UC 34096
Check
Formulation
WP
IV
E
E
D
E
E
E
E
E
E
Liq
IV
" Lbs. A: I./A
0.5
0.5
0.5
0.75
0.56
+
0.28
25 Ibs. dust
0.75
2.00
0.5
+
2.0
2.0
0.5
1.0
2 qts.
0.5
Ave. no. larva/head
0
0
.075
.075
.100
.100
.125
.125
.150
.175
.175
.175
.225
.400
1.375
1/Ten head cabbage, sample per plot.
- Ten head cabbage, sample per plot.
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Table 7. Control of cabbage
Treatment
Amdal 6000 WP
Amdal 6000 WP
Thuricide HP Powder
Furadan
Thiodan
Thiodan + Pyrenone 606
Azodrin
Azodrin
Fundal
Gardona
Thuricide slurry
Check
1/ 10 heads each plot.
Table 8. Control of Plusiinae
1970 /.
loopers on let'.uce during spring season, 1970.
Total number of loopers
Lbs. A. I./acre on 40 heads.
1.0
0.75 + 2 oz.
1.0
2.0
0.5
1.5
2 qts.
on celery: Number of loopers per plant, Spring
Insecticide
Amdal
Monitor
SBP1382
Azodrin
N-2596
Sevin
Sevin
Sevin
Furadan
Check
Formulation
Lbs. A. I./A
1.0
0.75
0.25
0.75
1.00
6.00
4.00
2.00
3.00
Mean No. Loopers/plant
.66
1.41
1.71
2.58
2.66
3.45
3.79
1/ From six plant sample per plot
2/ Twice weet~ ; applications
3/ A single soil application.
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Literature Cited
(1) Canerday, T. Don and F. S. Arant. 1966. The looper complex in Alabama
(Lepidoptera, Plusiinae) J. Econ. Entomol. 59 (3): 742-743.
(2) Genung, W. G. 1955. Fla. Agr. Exp. Sta. Ann. Rept., P. 223.
(3) 1957. Some possible cases of insect resistance to insecti-
cides in Florida. Proc. Fa. State Hort. Soc. 70: 148-152.
(4) 1960. The bean leaf skeletonizer AuloDtu.si: eiena, and
its control on bush snap beans in the Everglades. J. Econ. Entomol.
53 (4): 566-569.
(5) 1959. Observations on and preliminary experiments with a
polyhedrosis virus for control of cabbage looper Trichoplusia ni (Hbn).
Florida Entomol. 42 (3): 99-104.
(6) Greene, G. L., W. G. Genung, R. B. Workman and E. G. Kelsheimer. 1969.
Cabbage looper control in Florida -- a cooperative program. J. Econ.
Entomol. 62 (4): 798-800.
(7) Habeck, D. H. 1968. Annotated key to the Plusiinae moths of Florida
(Lepidoptera: Noctuidae). Entomology Circ. No. 72, Florida. Dept. Agr.
Div. of Plant Industry.
(8) Hensley, S. D., L. D. Newsom and J. Chapin. 1964. Observations on the
looper complex of the noctrid sub-family Plusiinae. J. Economol. 57(6):
1006-7.
(9) Janes, M. J. and G. L. Greene. 1970. An unusual occurrence of loopers
(Noctuidae: Plusiinae) feeding on sweet corn in Florida. J. Econ.
Entomol. (In press).
(10) Kimball, C. P. 1965. Lepidoptera of Florida. Fla. Dept. of Agr.,
Division of Plant Industry.
(11) Watson, J. R. 1917 Florida truck and garden insects. Fla. Agr. Exnt.
Sta. Bull. 151.
(12) Watson, J. R. and A. N. Tissot. 1942. Insects and other pests of FloriaR
vegetables. Fla. Agr. Exp. Sta. Bull. 370.
(13) Wilson, J. W. and N. C. Hayslip. 1951. Insects attacking celery in Florida
Fla. Agr. Exp. Sta. Bull. 486.
EES 70-12
400 copies
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