ivin, C. L. Smith. H. E. Parish, and W. L. Barrett, Jr.,
Division of Insects Affecting Man and Animals
number of years there has been a great need among owners of
3 of domestic animals in the screwworm-infested area of the
for an efficient remedy which combines materials that will
7ms infesting wounds and protect susceptible animal tissues
;tation. Previous recommendations by the Department of Agri-
required the use of one material to kill the maggots in the
econd to prevent reinfestation. Where large numbers of ani-
e treated, this method is time-consuming and leads to care-
)h results in failure to kill all the worms.
rch by the Bureau of Entomology and Plant Quarantine during
Ll has developed a remedy which, when applied to infested
fficient in rapidly killing all screwworms in a wound. At
a this remedy gives as good protection to all wounds against
ttack as materials heretofore recommended for this purpose,
r protection. 2/
"emedy is relatively inexpensive and consists of a correct
of the two principal materials at present advocated by the
f Agriculture for the treatment and prevention of screwwQrm
is remedy has not been tested throughout the screwworm-in-
)f the United States, but experiments conducted in Texas indi-
can be used generally throughout the Southwest.
search is under way on a number of different materials and
t show promise in screwworm control; however, experimental
the mixture described herein have been so satisfactory that
leuided to give this formula to the public and in the future
i changes in the recommendations as the later results may
The remedy known as Formula (or Smear) No. 62 is composed of the
Diphenylamine / (technical grade) - 3-1/2 parts by weight
Benzol 3/ (commercial) ------- 3-1/2 parts i
Turkey red oil (pH-10 or neutral) - 1 part i
Lamp black A/ ------------ 2 parts i
The diphenylamine is dissolved in the benzol, preferably by plac-
ing the two substances together and allowing them to stand 12 or 24 hours.
In no event should the dissolving of the diphenylamine in benzol be at-
tempted by heating over an open flame. Benzol is highly flammable and
should be kept away from flames and lighted cigarettes or cigars. If heat
is used to hasten solution, the container holding the benzol and di-
phenylamine may be placed in a vessel of hot water, the benzol container
being left uncorked until the diphenylamine is dissolved.
After the diphenylamine is dissolved the turkey red oil is added
and the mixture thoroughly shaken. The lamp black is then stirred in
gradually and the mixing continued until the compound attains a smooth
even texture of about the consistency of molasses. It is then ready for
Use of Remedy on Wounds
The remedy is best applied with a 1-inch paint brush.
In treating an animal infested with screwworms, the material is
swabbed into the wound, care being taken that it is pushed well into all
the pockets ade by the maggots and painted around the wound where blood
and wound exate have made the surrounding tissue attractive to flies
and susceptible to infestation or to fly blows.
3/ Diphenylamine and benzol are two substances recommended by the
Department of Agriculture in Bureau of Entomology and Plant Quarantine
Circular E-481 for the treatment and prevention of screwworm infestations.
In this formula these substances are combined for greater efficiency.
A/ The quantity of lamp black necessary to give the proper consist-
ency to the smear will vary somewhat with the grade used. The grade of
lamp blach used in the formula is that ordinarily sold by lumber yards
and paint stores for tinting paints. Besides imparting the proper tex-
ture to the e ear, lamp black appears to increase the killing action of
benzol and to impart a greater efficiency to diphenylamine for protecting
the wound against infestation.
It is not necessary to remove the dead worms from the wound, bu
most of the larger dead worms may be picked or wiped out with the brush
if desired. If the worms are removed the wound should be treated again
with the smear before the animal is released.
For protecting uninfested wounds, such as those caused by shear
cuts, castrations, dehorning, and docking, it is sufficient to cover he1
raw tissues and surrounding area thoroughly with a coating of the saear.
In treating castration wounds some of the material should be pushed
slightly into the openings of both sides of the scrotum.
This remedy kills screwworms quickly, and after its application
large numbers of them soon drop out of the wound, carrying a considerable
amount of the protective chemical with them. For this reason it is indi-
cated to be a good practice to apply a second treatment from 24 to 48
hours after the first one to insure a proper coating of the wound sur-
face. Thereafter, under average conditions, regular treatments twice
each week should be given until the wound is healed. It is especially
recommended that infested animals be kept in a hospital pasture when this
schedule of treatment is followed. When flies are unusually active and
abundant more frequent treatments may be necessary.
This material has been applied to wounds on several hundred sheep,
goats, and cattle, and no harmful effects have been observed. Further-
more, in tests in which large doses of the mixture, as well as diphenyl-
amine alone, were applied to sheep and goats, and in which Dr. W. C
Mitchell of the Bureau of Animal Industry cooperated, no ill effects
whatever were apparent.
This smear will cost approximately $1.50 per gallon. and I galilo
will treat from 200 to 250 wounds one time.
Precautions in Preparing and Using Screwworm Smear No. 62
1. Prepare the remedy well away from open flames and do not have
lighted cigarettes or cigars around during the process.
2. Benzol, in the form in which it occurs in the smear, is highly
volatile and will evaporate quickly from the smear if left in an open
container. It is therefore advisable that the smear be kep t igtly
covered in a cool place when not in use. It is also recommended that only
an amount necessary for a few days' use be removed at a time from the
larger supply container. Even when animals are actually being treated
the container should be kept covered as much as possible. In case the
smear, through evaporation, becomes too thick for easy application, an
additional amount of benzol may be stirred in to bring it back to its
UNIVERSITY OF FLORIDA
4 4- I '.s
3. When infestations located near the eyes are being treated,
care should be taken not to get an excessive amount of the smear into the
unaffected parts of the eye. If this is done accidentally it is ad-
visable to wash the eye immediately with plain water, as the material
is irritating to the eyes.
4. Do not add oil, grease, or any other substances to the formula,
or its efficiency will be greatly impaired, if not entirely destroyed,
Use of Remedy for Fleece Worms
Preliminary tests on sheep infested with fleece worms, or wool
maggots, show that Formula No. 62 is efficient in killing these worms
and gives a considerable measure of protection against reinfestation.
The material is applied to the affected part and well rubbed into
the wool with a brush.
Source of the Material
For the information of those who wish to purchase the ingredients
for- th mixing of this smear there is given below a list of companies
vihiclh ianufacture then. No claim is made that the list is complete, nor
is e ny guarantee here expressed or implied for the products of the com-
D r hnyJaiine should be obtainable from the larger wholesale drug
co~panins i- cre,,,o: -iufestod territory. It is manufactured by the
E. i Du Pont dc Ne.ours & Company, Inc., Wilmington, Del.
icderle Laboratories, i- ., 30 Rockefeller Plaza, New York, N. Y.
EastmIan Kodak Cox pany, Chemical Sales Division, Rochester, N. Y.
The Dow Chemical Company, Midland, Mich.
Turkey red oil is manufactured by the following companies:
Apex Chemical Co., iic., 200-214 So. First St., Elizabethport,
L. 2onneborn Sons, Inc., 88 Lexington Ave., New York, N. Y.
Lamp black is fianufacturcd by the following companies:
General Carbon Co., Los Angeles, Calif.
The L. Martin Co. (Germantown Eagle or Velvet Brand), Tacony, Pa.
Whittaker, Clark & Daniels, Inc., 260 West Broadway, New York,