- Permanent Link:
- Systemic insecticides for cattle grub control
- Series Title:
- Everglades Station Mimeo Report
- Harris, E. D
Genung, William G., 1915-1982
Chapman, H. L ( Herbert L. ), 1923-
Everglades Experiment Station
- Place of Publication:
- Belle Glade Fla
- Everglades Experiment Station
- Publication Date:
- Physical Description:
- 4 leaves : ; 29 cm.
- Subjects / Keywords:
- Warble flies -- Control -- Florida ( lcsh )
Cattle -- Diseases and pests -- Florida ( lcsh )
Larvae ( jstor )
Cattle ( jstor )
Wildlife damage management ( jstor )
- non-fiction ( marcgt )
- General Note:
- "July, 15 1958."
- General Note:
- Caption title.
- Statement of Responsibility:
- E.D. Harris, Jr. , W.G. Genung and H.L. Chapman, Jr.
- Source Institution:
- University of Florida
- Rights Management:
- All applicable rights reserved by the source institution and holding location.
- Resource Identifier:
- 65388970 ( OCLC )
Everglades Station Mimeo Report 59-1
Systemic Insecticides for Cattle Grub Control .
E. D. Harris, Jr., W. G. Genung and H. L. Chapman, Ji.
The cattle grub, Hypoderma lineatum (De Vill.), which may also be called .
the heel fly or ox warble, has become of increasing concern to the Everglades
cattleman. During the winter and spring cattle can be seen running rapidly
across the field with their tails in the air. These animals are being chased
by a hairy fly about the size of a honey bee. These flies lay eggs on hairs
on the lower portion of the legs or the belly of the animal. The eggs hatch
in three to seven days and the small maggot or grub crawls down the hair and
bores into the skin. Each maggot tunnels through the animal's body for about
six months until it reaches the back. It bores a hole in the hide through which
it breathes. It stays at this location for about two months where it grows to
be about one inch in length. When mature the maggot squeezes its way through
the hole and falls to the ground where it seeks protection on or in the soil.
It then forms a hard skin about itself and remains in this condition which is
called the pupal stage for about a month before the case is broken open and an
adult fly emerges from it. Adult flies soon mate and the females begin laying
eggs on cattle. In the Everglades, grubs have been noticed in the backs of the
animals during nearly every month of the year, but mainly occur during a period
extending from about September through April.
Until recently there was no satisfactory method for controlling these pests.
The grubs in the backs of the animals could be killed by rotenone sprays or dusts
but at this time they had already caused the animal much irritation and damaged
the meat and the hide. About the only thing that this measure can accomplish is
to lower the population of adult flies but even this is ineffective unless all
of the cattlemen in an area participate.
Recently two insecticides that will kill cattle grubs anyplace within the
animal's body have been approved by the U.S.D.A. for use on cattle. These insecti-
cides, Trolene and Co-ral, are also effective against screw-worms, horn flies,
and many other insect pests of livestock. Both materials were tested this yeat
at the Everglades Experiment Station in an effort to find the most effective
material and the best month for application to control cattle grub.
Each animal was given only a single application of either Trolene or Co-ral
on May 6-7, June 3-4, July 8, August 22, or September 16. Ten yearling cattle
were treated with each chemical on each date. These cattle were approximately
eight to nine months old at the first treatment date. Trolene was administered
as an oral drench whereas Co-ral was applied as a spray to the backs of the
animals. Twenty-five animals were left untreated to determine the level of
infestation. The grubs in the back of each animal were counted at two week
intervals from October 11, 1957 until April 9, 1958, for a total of fourteen
Assistant Entomologist, Assistant Entomologist and Associate Animal Nutritionist,
July 15, 1958
At the time of treatment some grubs were already present in the backs of
September-treated animals. On October 11 there was an average of 0.4 grubs per
animal among the animals treated with Co-ral in September and 0.2 grubs per anima.
among those treated with Trolene in August or September. There were no grubs
found among the other treated animals. At this time there was an average of 1.6
grubs per animal among the untreated cattle.
The greatest number of grubs appeared in the backs of untreated animals on
January 15 (Table 1) and among the treated animals on February 12 when there was
an average of 2.7 grubs per animal among those treated with Trolene in June.
Either chemical applied during any month greatly reduced the number of grubs per
animal. The other treatments gave significantly better grub control than Trolene
applied in June. Otherwise the dates of treatment and the chemicals were about
equally effective on these two dates of observation.
The 14 dates of observation were averaged to give a comparison of the treat-
ments over the entire grub period (Table 2). The Co-ral treatment in May gave
significantly better grub control than all other treatments other than Co-ral in
July or August or the September Trolene treatment. The Trolene treatment in June
gave significantly poorer control than the other treatments. The relatively poorer
control shown by this treatment may be related to the fact that the animals were
weaned in late May only a few days before receiving the June treatment. Co-ral
with an average of 0.07 grubs per animal over the observation period gave signi-
ficantly better cattle grub control than Trolene with an average of 0.37 grubs
It is advisable to apply control measures as soon as possible after grubs are
in the body of the animal, but after most of the adult fly activity has passed.
Although the May treatments gave good control this year, a treatment in May might
possibly be a little too early during some years, as adult fly activity may occur
later. Therefore, the best month for treatment would seem to be either June or
Trolene is marketed as a bolus which can be administered in a multiple ball-
ing gun or mixed with water and applied as a drench. Co-ral is marketed as a
wettable powder to be mixed with water and applied to the backs of the animals as
a spray. Before using either material the instructions on the container should
be read thoroughly and carefully followed.
Table 1. Number of cattle grubs in the backs of treated and untreated
animals on January 15, 1958
CHEMICAL TREATMENT DATE GRUBS/ANIMALa
Co-ral May, July 0
Trolene May, September 0
Trolene August 0.1
Co-ral August, September 0.1
Co-ral June 0.2
Trolene July 0.4
Trolene June 1.9
UNTREATED .--. 18.1
a Figures joined by the vertical line are not significantly different;
those not joined by the line are significantly different.
Table 2. Number of cattle grubs in the backs of treated and untreated
animals averaged for 14 observation dates.
CHEMICAL TREATMENT DATE GRUBS/ANIMALa
Co-ral May 0
Co-ral July 0.04
Trolene September 0.04
Co-ral August 0.09
Co-ral June 0.11
Co-ral September 0.14
Trolene May 0.19
Trolene August 0.23
Trolene July 0.29
Trolene June 1.13
UNTREATED ---- 8.58
a Figures joined by the same vertical line are not significantly
different; figures not joined by the same vertical line are signi-