PASTURE AND LIVESTOCK INSECTS AND
'I. G. Genung
This report presents the results of experiments conducted
in the Everglades area relative to the identification and
possible methods of control of insect pests that cause
damage to pasture crops and affect the production of live-
Everglades Station Mimeo Report 55-8
Belle Glade, Florida
January 17, 1955
PASTURE AND LIVESTOCK INSECTS AND
VT. G. Genungi/
Insect problems of pasture crops are increasing in South Florida as
a result oi the increasing acreages in improved pastures. Under conditions ex-
isting on native range this problem was of minor importance, but the introduc-
tion of and rapid expansion in acreages of the nore lush andd utritious pasture
grasses and legumes has created conditions that are attractive to an ever grow-
ing list of insect pests. Under improved pasture conditions insect control has
assumed a major role in the pasture management picture.
Pasture insect research at the Everglades Station has been designed
to answer as many of the rancher's questions and problems as possible and the
program has been kept on a more practical basis through conversations and
visits with cattlemen at the scene of the problem. A brief discussion of the
principal questions relative to the pasture insect problem follows.
Economics of Pasture Insect Control:
Some ranchers question the economics of chemical control of pasture
insects. Considerations of the losses in both gross yield and nutritive levels
of the pasturage have established that the economics of chemical control of many
major pests on these lands is sound in most cases. Most cattlemen have ob-
served the great injury inflicted by caterpillars of the various armyworm types,
as well as the damage caused by yellow sugar cane aphid, Sipha flava, and green-
bug, Toxoptera graminum, to Pangola.grass, oats and young rye grass. Chemical
control often means the difference between good grazing and almost no grazing.
In cases where insecticide applications appear./too costly, it is often well to
consider all factors before reaching a conclusion. The purpose here is to bring
to ranchers' attention some points that are frequently overlooked.
Effect of Sucking Insects on Yield and Nutritive Value:
It was found by workers in iaine many years ago, that heavy leafhopper
infestations cause a loss in both tonnage and protein content. 'Recent studies
at this Station have showv the loss in protein-content of Pangola grass due to
moderate infestations of yellow sugarcane aphids to be nearly fifty percent.,
Under sustained infestation, the gross yield of Pangola grass is greatly reduced,
and in many cases large spots are completely killed out. Tables 1, 2 and 3 show
the large differences in protein content obtained between aphid infested and
uninfested grass. Apparently certain mineral elements are also reduced by aphid
infestation.: The-picture then, under heavy aphid infestation, seems to be this:
half as muchgrass with half the protein.content found in uninfested grass
/ 'Assistant Entomologist, Everglades Experiment Station, Belle Glade, Florida,
Frost Injured and Aphid Injured Grass:
Doubt is frequently expressed as to the wisdom of treating grass that
may soon be frost killed. Grass that is severely injured by aphids is low in
vitality and generally comes back slowly. Aphid free, frost injured grass comes
back more rapidly with the resumption of favorable growing conditions. The
aphids are not killed by temperatures occurring in this area and many survive
and further inhibit the recovery of infested pastures. Table 4 compares the
number of Pangola shoots returning on area of aphid control and area having no
control. Counts were made 2 weeks after frost.
Replacement of Pangola with a More Aphid Resistant Variety:
Replacing Pangola vith Carib, St. Augustine, Para or other varieties
might be a permanent solution to an aphid problem but cannot be definitely said
to be so. Yellow sugar cane aphid has been found reproducing successfully on
over 40 species of grass plants in South Florida, and the history of entomologi-
cal research contains many instances of host changes by insects. To illustrate:
tobacco previously had not been subject to serious attack by green peach aphid,
but since 1946 green peach aphid has been a major pest of tobacco. Since suc-
cessful reproduction by pasture aphids has been seen in several instances on the
other major pasture varieties, it is difficult to believe that removal of Pangola
would be a permanent solution to the aphid problem of ranchers.
This phase of insect control has made phenomenal strides in the last
decade. The development and know-how in use of the phosphatic and chlorinated
hydrocarbon insecticides have given us the means to practical control of most
of our insect pests, though many problems remain and others have arisen.
Most of our recommendations, summarized in Table 5, are given with a
range of dosages. This is done because conditions vary; density of pasturage,
temperature and other factors affect results. The lesser amounts of phosphatic
insecticides suggested have given excellent control of aphids on sparse to mod-
erate pasturage, with careful applications, v&en day temperatures are not
unusually low. Denser growth requires the higher dosages.
Protection Period With Phosphatic Insecticides:
Applications of phosphatic insecticides for aphids at the Everglades
Station in October appeared to give almost perfect control. TJeekly counts in-
dicated a slow, gradual reinfestation in treated strips. Grass in the check strip
was severely injured and killed out in some spots. lTo months after application,
the population in the treated strips had not attained serious proportions. Since
other adjacent areas, as well as the check, were infested there was ample oppor-
tunity for the aphids to increase and spread. It is believed that ranchers could
duplicate the degree of control obtained in this test. Table 6 shows results of
this trial. The figures are timed counts and show the total number of aphids
that could be found in eight minutes of counting for each strip treated with the
Aerial vs Ground Applications:
In checking behind aerial applications of both dusts and concentrate
sprays, we have found control to be good in some cases and poor in others.
Probably experienced pilots generally do a good job. In some instances large
swaths were observed that had been missed while other strips had excess amounts
of insecticide. Other applications observed were uniformly made and appeared
to give control comparable to, ground equipment. It appears to the writer that
ground applications are less wasteful of insecticides.
Retail prices of insecticides vary and are usually somewhat cheaper
the larger the quantity purchased. For example, a 5 gallon can of DDT 25%
emulsion may cost '12.25 per gallon, vhile a 30 gallon drum may cost $1.90 per
gallon. Some area differences in prices also occur. The following are approx-
imately the prices of the materials most commonly used on pastures:
Material Emulsifiable W7ettable powder
Parathion $7.00 per gal. 25% emis. $.40 per lb, 15% wettable
Toxaphene -.25 per lb. h40 wettable
Chlordane -- .60 per lb. 40% wettable
DDT $2.25 per gal. (25%) in .35 per lb. 50% wettable
$1.90 per gal. (25) in
30 to 50-gallon drums.
Biological Control of Pasture Insects:
This phase of insect control in pastures has not been extensively in-
vestigated. Biological control is often of considerable benefit in combating
insects of foreign origin that have entered our boundaries without the natural
enemies that tend to keep them in check in their native regions. Rhodes grass
scale (Antonina graminis) is such a pest. The U.S.D.A. Entomologist at this
Station, Mra. D. D. Ouestel, has released a small wasp, Anagyrus antoniniae,
which is parasitic upon this pest, and he has recovered parasitized scale in
large numbers at and near the points of release on several occasions, indicating
establishment of the beneficial wasp. If the parasites continue to thrive, a
noteworthy contribution will have been made, since Rhodes grass scale is par-
ticularly difficult to control by insecticides.
Natural enemies of our native insects are generally present and are
very helpful in keeping populations of injurious species from reaching even more
injurious proportions. Insects are attacked by many species of insect para-
sites and predators. Virus, fungus and bacterial diseases take their toll of
these pests. Epizootics of such great proportions that, if applied to the human
population of the world would probably leave only a few hundred people alive,
destroy many insect populations. Such typical pasture birds as meadowlarks,
redwings, grackles, killdeers and many others are of inestimable value in the
reduction of worms and grasshoppers. That the injurious insects do so much
damage in spite of these factors should make us realize the value of natural
control. 7e cannot estimate the magnitude of the control problem should these
insect enemies suddenly cease to exist. Some of these valuable parasites and
predators are listed in Table 5.
Agronomic Practices in Relation to Pasture Insect Problems:
Certain agronomic practices have been observed in relation to the
pasture insect problem. Ensilage of Pangola grass during the fall is a prac-
tice to be recommended. The material can be harvested before the protein con-
tent is seriously depleted by aphid feeding during the late fall and winter.
Pastures mowed for this purpose can be treated with smaller amounts of insecti-
cide. The regrowth should be sufficient for good grazing before frost.
It should be remembered that late summer and fall fertilization may
encourage aphid infestation, particularly on mineral soils, although some aphid
response to fertilization has been indicated on organic soils of the Everglades.
Seeding rye grass, oats or other cold resistant grass in the pasture,
while a good practice in order to obtain improved winter grazing, may aid in re-
taining an aphid population unless control measures are taken. It has been ob-
served in such cases that if Pangola grass is frost killed, many aphids tend to
migrate to the cold resistant winter grasses and, after the Pangola grass resumes
growth, reinfest that variety from the cold resistant source. Treatment of these
grasses with a phosphatic insecticide would appear to be a good control practice
in such cases.
Grass Varieties And Insect Susceptibility:
Selection of a pasture variety on the basis of attractiveness or resis-
tance to insect pests may have some merit, particularly in regard to aphids, if
planning pasture expansion or if dissatisfied with a variety presently in use.
The agrononic factors of cold susceptibility, soil and fertilization require-
ments, water tolerance and survival under summer temperatures should be recog-
nized in considering such a change. whilee space does not permit a discussion of
every individual variety and its insect pests, these data are summarized in
Table 7. The various grasses are scored from 0- to $ on basis of susceptibility
to various species of insects.
Livestock insects, particularly biting flies such as mosquitoes, horn
flies and horse flies, often occur in large numbers and are so annoying that
considerable loss of weight and decrease in milk flow may be observed. Mosquito
populations during rainy periods often become so great that weak animals may
die from loss of blood and smothering due to large numbers of the insects plug-
ging the nasal openings.
Horse fly control has not been generally attempted or considered prac-
tical in Florida. V. E. Dove reports protection up to two weeks in South
Carolina and Illinois with pyrenone insecticides.
Horn fly control can be obtained by spraying tith DDT at 25 pounds of
50% wettable powder in 100 gallons of water, using two to three quarts per
animal. Toxaphene at a rate of 10 pounds of 10% wettable per 100 gallons appears
to be superior to DDr. Dairy animals should not be sprayed with DDT, toxaphene,
chlordane or BHC. Control on these can be obtained with methoxychlor at about
9 pounds of 50% wettable per 100 gallons. Pyrenone insecticides are also safe
for use on milk cows, These materials give excellent initial kill but have
poorer residual effects than the chlorinated insecticides.
For mosquitoes, area treatment with fogging machines after a heavy
flight is the best method of control. Jeep foggers in which the insecticide is
gravity fed into the manifold and fogged out the exhaust are popular. Jeeps
can also be equipped with venturi exhaust generators. A 5% DDT-fuel oil solution
is most commonly used although lindane and BHC emulsions have been effective.
The control of lice, ticks and cattle grubs are taken from Handbook of
Pesticides and Their Use in Florida. These data are summarized in Table 8.
Table 1. Analyses of Pangola blades selected under uniform conditions except
for aphid infestation.
Sample Percent ppm Percent
Description K Na Ca P Fe Protein
Aphids retained 1.34 .39 .14 .34 77 7.07
Aphids removed 1.32 .42 .14 .34 75 6.98
Uninfested 2.02 .43 .11 .18 95 19.48
Table 2. Differences in protein and mineral element contents of paired Pangola grass
spot infested pasture. Differences in protein content between infested and
to aphid activity.
samples taken at random in a
uninfested grass is attributed
Avg. 12.13 22,67
Percent Ca Percent Mg
Infested UninTested Infested Uninfested
.36 .33 .42 .52
.36 .48 .32 .43
.42 .48 .29 .47
.48 .66 .35 .54
.36 .63 .19 .52
.40 .52 .31 .50
P percent K
* Differences in Protein Significant at odds of 99:1.
Chemical Analyses made according to A.O.A.C. methods by A. E. Kretschmer, Jr. Assistant Soils Chemist.
Two grams of oven dried material used for each sample.
Table 3. Differences in protein contents obtained in laboratory scale
experiment, plants grown in crocks. Three plants were arti-
ficially infested and three plants kept aphid free.
Table 4. Number of new shoots of Pangola grass per square foot after a
killing frost at Everglades, from area of no treatment and from
area having single application of phosphatic insecticides two
months previous to frost.
No aphid control
Total ... 1282
Data on Pasture Insects and Their Control.
Syvmtoms of Infestation
AphidsI Yellow sugarcane aphid causes
a yellowing and reddening of
Yellow sugarcane infested grass. If not con-
aphidl trolled grass will turn brown
and be almost killed out in
Greenbug2 worst spots.
Corn leaf aphid3 Greenbug causes a yellowing
and browning. Injury some-
Rusty plum aphid4 times as severe as yellow
Mixed infestations of above
Pea aphid6 species have more the ap-
pearance of yellow sugarcane
Symptoms caused by the other
species are less distinct un-
der usual conditions of pop-
Yellow sugarcane aphid
has no internal para-
sites. Greenbug is
parasitized and some-
times controlled by a
Lady beetles8 of sev-
eral kinds feed on all
species of aphids.
Aphis lions9 and
Syrphus flys10 are al-
so important preda-
Fungus diseases often
kill many aphids.
- to 2 Ibs. 15% W. para-
thion per 100 gallons per
acre or 20 to 35 lbs. 1 or
2% parathion dust per acre
depending on density of
pasturage. 2 to 1 pint of
25% parathion emulsion is
also very effective.
pint of 400 TEPP is effec-
tive and is recommended in
cases where cattle must be
returned to pastures in less
time than that required for
other phosphatic insecticides,
Malathion sprays and dusts
are also effective. 22 and
5% malathion dust at 20 to
35 lbs. per acre or 1-2 lbs.
25% W. per 100 gallons per
acre, or 1 pint to 1 quart
- Sipha flava (Forbes)
- Toxoptera graminum (Rond)
- Aphis maids (Fitch)
-'T.yteroneura setariae (Thomas)
- Phopalosiphum subterraneum (Mason)
- Macrosiphum pisi (Klt)
7 Aphidius testaceipes (Cress.) 9 Chrysopa sp.
8 Cycloneda immaculate (Fab.) 10 Syrphidae: several species
Ceratomegilla fuscilabris floridana (Leng)
Scymnus dichorus (Cay.)
Scymnus collaris ( elsh.)
Scymnus terminatus (Say.)
Hippodamia convergens (Guer.)
Insect Species---- -
Table 5. continued ...
Parasites and Control by Safety period
Insect Species Symptoms of Infestation Predators Ground equipment for livestock
Armyworms1 Heavy infestations show Parasitic wapps Toxaphene sprays and lh days
Fall armyworm, badly eaten leaves. Pas- Bracmidaeu dusts 20 to 35 lbs.
Southern armyworm, tures sometimes almost Ichneumonidae5 10% dust per acre.
Striped armyworm, denuded if control measures 2 lbs. 140 wettable
a sugarcane army- are not taken. Parasitic flies per 100 gallons per acre.
Chlordane: 20 to 35 lbs. 14 days
Cutworms2 Ground beetles 5% dust per acre, or
Granulate cutworm Carabidae7 2 libs. 40% wettable per
Black cutworm 100 gallons per acre.
Grassworms3 blackbirds, grackles, DDT: 20 to 35 lbs. per 14 days
Various species of killdeers and many acre of 5% dust.
Moscis. other birds are par-
ticularly useful in
the destruction of
these insects, or they
are highly insecti-
varous and abundant in
lioscs raanda Fab.
1 Laphygma frugiperda (A-S)
Prodenia eradania (Cram.)
Prodenia ornithogalli (Guen)
Leucania latiuscula (H-sch)
2 Feltia subterranea (Fab.)
Agrotis ypsilon (Rott.)
3 Hoscis rapanda (Fab.)
4 IMeteorus vulgaris (Cress.)
5 Various Ichneumon flies
6 Archytus piliventris (WVulp.)
Eucelatoria rubentis (Coq.)
7 Calosoma sayi (DeJ.)
Calosoma scrutator (Fab.)
Scarites subterraneous (Fab.)
Table 5. continued
Natural Parasites Control: Chemical Safety period
Insect Species Symptoms of Infestation and Predators and Biological for livestock
Rhodes grass scale Grass may be severely browned Lady beetles feed on No practical chemical
and almost killed out in heavy the crawlers (early) control known. U.S.P.A.
infestations. Vfhitish scale stage, entomologists are work-
at nodes often under sheaths, ing to obtain biological
control with a parasitic
wasp3. Progeny of re-
leased parasites have been
recovered from some South
Florida areas indicating
parasite has become es-
Spittle bug2 Grass may short much brown- Not known. Toxaphene appeared to give 14 days
ing in heavy infestations, fair to good control in one
Froth or spittle like masses planting. Three lbs. 40)
at or soil level on small wettable Toxaphene per 100
stemmed grasses. Froth may gallons per acre are sugges-
occur further up stem on ted.
coarser type grasses.
1 Antonina graminis
2 Tomaspis bicincta
3 Pnagyrus antoniniae (Timberlake)
Table 5. continued .....
TI, r t Sn4 t4 in
C -- f, +T
I,.; t e es L:2!e %., .' L=
Jli ru I y
Sometimes a marginal
tip browning under con-
ditions of heavy popula-
DDT 5% dust at 20 to 35
Ibs. per acre,
DDT emulsion 1 quart per
100 gallons per acre.
DDT w.p, 2 Ibs. 50% per
100 gallons per acre.
Toxaphene 21 Ibs. 40% wet-
table per 100 gallons per
applied for aphid control
appear to give leafhopper
control for most species.
1 Hortensia similis
9rrrnn+rrnc! nf Tnfonf.a~inn
Degree of Aphid* control obtained with Phosphatic Insecticides for two months
period, A single application was made in each case. Tabulations show number
of aphids found in eight minutes counting.
1st week 2nd week 3rd week 4th week 5th week 6th week 7th week 8th week 9th week
Parathion, 15% wettable 0 0 3 1 21 67 28 70 97
1 lb. per 100
Malathion, 25%. wettable 0 0 0 4 7 6 20 31 51
2 Ibs. per 100
Parathion emulsion 0 0 0 6 16 33 28 69 92
Parathion emulsion 1 3 0 9 68 42 100 71 75
Malathion 50% 0 0 0 5 25 22 62 75 28
emulsion, 1 quart
Malathion 50% 2 0 0 0 24 20 99 117 59
emulsion, 1 pint
Check -':- 182 131 277 220 451 695 467 372 161
* Yellow sugarcane aphid Sipha flava (Forbes)
Greenbug Toxoptera graminum (Rond.)
*- Populations started declining in checks due to death of grass from aphid attack, and to greater activity of
parasites and predators.
Degree of susceptibility of certain grasses to the various pasture insects, based on observations in the Everglades
and adjacent mineral soil areas. A number rating explained in key denotes degree of susceptibility.
Key: 0 not observed after many inspections 3 moderate numbers --- denotes insufficient observations
1 very light numbers 4 heavy populations
2 light numbers 5 very heavy populations
Yellow sugar Corn leaf Small leaf- Large leaf- Spittle Rhodes grass Armyworms, Grass
Variety cane aphid Greenbug aohid hoppers hoppers bug scale etc. hoppers
Pangola 5 5 3 4-5 2 5 3 5 4
Para 2-3 1-2 3 1-2 3 3-4 4 5 4
Carib 2-3 2-3 3 4-5 2-3 --- 5 5
St. Augustine 1-2 0 0 1-2 1-2 2-3 -- 2 2
Vasey 2 2 1 --- -- -
Napier 2 2 2 --- ------
Crab grass -S 5 3-4 4 3 -- -- 4-5
Bahias 1 1 0 2-3 1 -- 2-3
Natal 2-3 2-3 -- -- -- -- -
Bermuda 1-2 2-3 3-4 5 2-3 2-3 4 4-
Rye-grass* 4 5 -- -- -- -
Fescue 1 1 0 1 -- -- -
Oats 3-4 5 -- -- -- -- -
Rescueagrass 3-4 3-4 --- --
Molasses grass 0 0 0 0 0 -- --- -- 5
* Attacked by aphid only when young.
Data on Animal Insects and Their Control.
Insect Species Description Control
MosquitoesI Glades mosquito often occurs in Area treatment with fogging
immense numbers about time of fall machines. A common device is
rains, a rather large black mosquito the jeep fogger, in which an
that has been known to kill weak emulsifiable chlorinated insec-
animals through loss of blood and ticide is piped into manifold and
smothering by clogging nasal open- the material fogged out of the
ings. exhaust. The insecticide is
gravity fed into manifold. DDT
and lindene emulsions are most
commonly used, in fuel oil.
Venturi tyoe exhaust generators
have also been used on jeeps for
area treatment in mosquito con-
trol. Probably venturi genera-
tor would be superior to above
1 Psorophora confinis
anci other Culicidae.
(The Glades Mosquito)
Table 8. continued
Small black fly smaller than housefly.
Clusters on flanks, back, shoulders and
heads of cattle; tail lashing, flank
twitching indicate infestations of
1 Toxaphene: has given best control of all
materials used at Everglades Experiment
Station. 10 lbs. 40/% wettable powder per
100 gallons water. -pply 2 quarts spray
per adult animal. Horn flys roost on animals
so building need not be sprayed unless other
species also are to be controlled.
2 DDT: gives good control at 25 lbs. 50%
wettable per 100 gallons but is less ef-
fective at lower rates. DDT does not appear
as effective as formerly.
3 Lindane: -1 lbs. 25% gamma isomer per 100
h Methoxychlor: Use Ilbs. 50% wettable per
100 gallons; this material may be used on
lactating dairy cows.
5 Perthane: appears to have considerable
promise but requires further testing,
6 Strobane: appears to have considerable
promise but requires further testing.
7 Pyrenone: gives excellent initial kill,
but has shorter residual than materials
mentioned above. May be used on lactating
1 Siphona irritans (L.)
Table 8. continued .....
Insect species Description Control
Cattle grub Grubs under skin form lumps on Most chlorinated insecticides applied as sprays
backs of infested animals, or washes to back of animals have failed to give
adequate control. Potenone is the most effec-
tive material and is sometimes used in combina-
tion with chlorinated insecticides; 10 lbs.
Ox warble1 Cattle being attacked by egg rotenone powder plus 6.25 lbs. BHC 6% gamma
or laying adult flies buck and isomer or 10 lbs. rotenone plus 20 lbs. of 50%
Heel fly often run in terror stricken wettable DDT. It is essential to use power
manner, sprayers or to scrub backs of animals to loosen
Ticks Spray: 64 lbs. BHC wettable, 6F gamma isomer
plus 121 lbs. DDT 50% wettable,
Dip: h lbs. BHC wettable 6% gamma isomer plus
8 lbs. DDT 50% wettable per 100 gallons-.
1 Hypoderma lineatum
* Control derived from Handbook on Pesticides
and their Use in Florida, compiled by Fla.
Agr. Exp. Stations, Fla. Pgr. Extension
Service, Fla. Industry Organics Committee,
.and U. S. Fish and Uildlife Service.
Table 8. continued .....
* Little success in chemical control of these insects has been obtained.
Pyrenone insecticides are reported by Dove to give protection up to a
week or more (1).
These insects have been very scarce during control trials in Everglades
area. DDT, Methoxychlor and Lindane at rates given under hornfly control
are suggested. Other chlorinated insecticides are also known to be effec-
tive including chlordane and BHC wettable powders. Barns and other build-
ings housing livestock and accessible to flies should be treated to get
control of stable flies.
These insects may be controlled by spraying with DDT 50% wettable, 25 lbs.
per 100 gallons; BHC wettable powder as spray or dip, or spray using 50%
wettable Chlordane 16 lbs. per 100 gallons.
1 Tabanus atratus (Fab.)
3 Stomoxys calcitrans (L.)
4 Various species Haematopinidae
2 Chrysops sp.
* Horse fly control from V. E. Dove:
Horseflies (Tabanidae) Fla. Entomologist
Vol. XXXIII No. 3, Cept. 1950.
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