S" JAN 2 3 1964
Table NORTH FLORIDA EXPERIMENT STATION
_FLA. STA. MIMEO REPORT NFS 64-4
A PRELIMINARY REPORT OF FLEA BEETLE CONTROL ON SHADE TOBACCO
William B. Tappan
EarliL- Assistant Entomologist
3-13/Okina The tobacco flea beetle, Epitrix hirtipennis (Melsheimer), was reported by
Junegold/E lin and Madden (1942) as a major pest of shade tobacco in the Quincy area. They
FV 345-10 .:hat satisfactory insecticidal control resulted from applications of barium
Maygold ;dlicate, paris green, or rotenone dusts. About 1947, DDT was made available to the
Maygolcdcco grower, and became the primary material for flea beetle control. The beetle was
13-54/Nen.nger a major pest of the crop after the introduction of DDT, but a small population
Robin red on volunteer tobacco and other cultivated and wild hosts. Since that time, endrin
Bonanza ifan, parathion, TDE, and toxaphene were added to the list of effective insecticides.
12-28/Ranc however, toxaphene was deleted from the recommended control program due to adverse
Maygold/0Os of flavor tests.
B3-777 Other types of tobacco also suffered from flea beetle attack probably more so
Flordaque'riade tobacco due to less frequent insecticide application during the growing season.
Meadowlark. As 1957, Dominick (1959) found that foliar applications of DDT on flue-cured
2-6/37-23 'r*.;n Virginia were more effective in preventing flea beetle injury than soil
Flordahome3. .s of some other chlorinated-hydrocarbon insecticides. Recently, however, Dominick
Flordaque.. 4 norted flea beetle control difficulties with foliar applications of various
B7-45 :~t; .ai-hydrocarbon insecticides, but obtained very rapid control with Zectran. On
F55-74 1 '- co in 1962, pdio control of the pest was observed in commercial plant beds,
Suwannee/':- i fields which had bhep treated with 1% parathion + 10% DDT or 1% parathion + 2%
FV 240-1 1- weekly schedule. This indicates that the beetle was once again increasing in
Suwannee 3 & as a major pest.
F62-77 Chamberlin and Madden (1942) observed that most flea beetle injury to shade
Texas A1624 "n the field resulted from the foliar feeding'of second-brood adults. This
Sunhigh/Oka -n occurred in 1962, whenrimost control failures were reported by growers a few days
FV 243-64 tve second brood emerged. The effectiveness of flea beetle control on shade tobacco
Saturn/S3S ike that on any other type of tobacco in that it is dependent upon prevention of
2-10/Nema? to the foliage.
Fortyniner Recently, Schuster (1963) found that the tobacco flea beetle transmitted tobacco,
3-17/37-6 ;t virus from certain infected hosts to susceptible hosts. Earlier, Glass (1940) had
4-14/37-1i that the flea beetle fed occasionally upon a number of hosts, a few of which belong
7 same genera reported by Schuster (1963) as hosts of tobacco ringspot virus. Wolf
noted that the ringspot virus probably occurs throughout the world, wherever
diam- o is grown commercially, but is seldom destructive except to scattered plants. He
** diaimpinted out that weed hosts, some of which are common to the Quincy area, are
ily responsible for survival of the virus, and that means of transmission to tobacco
definitely known. Insect vectors were suggested by Valleau (1932), but Fenne (1931)
bible to transmit the disease from burley tobacco using the flea beetle, E. hirtipennii
iimer), and hornworm, Protoparce quinquemaculata (Haworth). Later, Schuster (1963)
that the flea beetle did not transmit the disease from infected burley tobacco to
cucumber. In view of these facts, however, the tobacco flea beetle could be a
ial vector of the ringspot virus to shade tobacco, and its capability of disease
mission only compounds its undesirability on the crop. Therefore, a preliminary
'as conducted in 1963 to determine the effectiveness and phytotoxicity of several
trials for control of second-brood adults, and to observe the incidence of ringspot
n hosts of the flea beetle.
p:.. aratidns for planting were begun in October of 1962. On February 15,
was injected broadcast with Telone, at 17 gallons per acre, for nematode
field was planted with Dixie Shade variety on April 4.
0.-Nts were four rows wide and approximately 32 feet long. Rows were 4 feet
each row contained 32 plants set on 12-inch centers. The two center rows
the experimental plot, and the remaining two rows served as buffer rows
.Vacant alleys, 8 feet wide, separated blocks of plots. A randomized
-izck design was used and treatments were replicated three times.
`.'-, nations s of the various dust treatments were begun on May 21, which was
l y three weeks before the second-brood adults began emerging on June 13. This
: saary to obtain additional information regarding control of other insect pests
ie crop. Some of the materials were combined into the same formulation, which in
nercial practice reduces the cost of application and gives added protection from other
-sects and diseases. Four applications, at various rates and concentrations, were made
ith Hudson 806B rotary hand dusters at 7-day intervals. The last application was made
- r .ine 11, since the crop harvest was completed on June 20.
The number of flea beetle-injured leaves, regardless of the extent of injury, was
counted on June 17, six days after the last treatment application. The last remaining
tix leaves of harvestable size were counted on each of ten random plants in the two center
rows. Phytotoxicity observations were made concurrently, and the treatments were rated
by the following system: 0 = none, 1 = slight, 2 = moderate, 3 = heavy, and 4 = severe
RESULTS AND DISCUSSION
A definite line of demarcation existed between the first and second broods, as
all leaves injured by the first brood had been harvested before the second brood emerged.
The counts showed no significant difference between the treated plots, but there was a
difference between plots treated with 5% Zectran, 3% Nia 9203, 1% parathion + 10% Sevin,
5% Bayer 44646, 1% parathion + 10% DDT + 6.5% zineb, 10% Sevin, 5% Kelthane, and the
untreated plots (Table 1). The best protection resulted from treatments with 5% Zectran
and 3% Nia 9203, although these materials did not prevent some injury to the foliage.
Under commercial conditions, 1% parathion + 10% Sevin and 5% Bayer 39007 would not be
suitable in the formulations tested for application on shade tobacco due to phytotoxicity.
The results showed that parathion + Sevin was much more phytotoxic than Sevin alone,
which indicated that these materials were not compatible in dust formulation.
In addition to the hosts published by Glass (1940), thorny-amaranth, Amaranthus
spinosus Linnaeus, and Florida-beggarweed, Meiobomia purpurea Vail, were found to be two
new hosts fed upon occasionally by the flea beetle.
Wild hosts of tobacco ringspot virus are prevalent in the Quincy area and could
pose a problem should the virus occur in any of these hosts. No plant was found with
ringspot symptoms, which would indicate that the disease, if present, must be endemic.
There does not appear to be any reason for serious concern regarding an outbreak of the
disease, for it is probable that the disease could be effectively contained through flea
The incidence of flea beetles in treated commercial fields has increased since
1961. Preliminary evidence of control in 1963 did not compare with that prior to 1962.
From 1955 until 1962, no live flea beetles were observed in any treated shade tobacco
field in the area. Observations in 1963 showed that 1% parathion + 10% DDT or 1% parathiol
+ 2% endrin were less effective than in 1962, since at least two applications per week,
rather than one, were required to effect control. The increased incidence of the beetle
in treated fields suggested that the pest has developed a certain degree of tolerance to
the presently recommended insecticidal materials. Although the chlorinated-hydrocarbon
insecticides give some control, they are far from being adequate. The recommended
materials must be replaced with newer effective materials, and those showing the most
promise belong to the carbamate and organic phosphate groups.
Control of the tobacco flea beetle on shade tobacco in the Quincy area with the
recommended insecticidal materials began failing in 1962. Observations showed these
materials to be even less effective in 1963. A preliminary study was conducted in 1963
to determine the effectiveness and phytotoxicity of various dust materials for control of
second-brood adults, and observe the incidence of tobacco ringspot virus in hosts of the
No significant differences between treated plots were found, however,
significantly fewer flea beetle-injured leaves were found in plots treated with 5%
Zectran, 3% Nia 9203, 1% parathion + 10% Sevin, 5% Bayer 44646, 1% parathion + 10% DDT +
6.5% zineb, 10% Sevin, and 5% Kelthane than in untreated plots. The most effective
materials from the standpoint of protection were 5% Zectran and 3% Nia 9203. Treatments
with 1% parathion + 10% Sevin and 5% Bayer 39007 were phytotoxic; apparently parathion
and Sevin are not compatible.
Two new hosts, Amaranthus spinosus Linnaeus and Meiobomia purpurea Vail, were
found to be occasional food plants of the beetle. No symptoms of tobacco ringspot were
observed on any host of the beetle, and the disease is probably of low incidence in the
area, if present at all.
All evidence indicates that the flea beetle has developed a certain degree of
tolerance to the recommended control materials. Those materials will have to be replaced
with newer, more effective materials, probably from the carbamate and organic phosphate
Chamberlin, F. S., and A. H. Madden.
tobaccos in the Southern
C. B. 1959.
1942. Insect pests of cigar-type
districts. U. S. Dept. Agric. Circ.
Feeding of overwintered tobacco flea beetles and
emergence following soil treatment with insecticides.
Ent. 52(4): 753-4.
C. B. 1962. Tests with insecticides applied to the soil and
foliage for tobacco flea beetle control. Jour. Econ. Ent.
B. 1931. Field studies on the ring-spot disease of Burley
tobacco in Washington County, Virginia. Phytophathology 21:
H. 1940. Host plants of the tobacco flea beetle. Jour. Econ.
Ent. 33(3): 467-70.
M. F. 1963. Flea beetle transmission of tobacco ringspot virus
in the lower Rio Grande Valley. Plant Disease Reptr.
Valleau, W. D. 1932. Seed transmission and sterility studies of two
strains of tobacco ringspot. Ky. Agric. Expt. Sta. Bull.
Wolf, F. A. 1935. Rev. and enl. 2nd ed. 1957. Tobacco diseases and
decays. Seeman Printery, Inc., Durham, N. C. 140-6.
Table 1.- Effectiveness and Phytotoxicity of Four Ihsectii
of Second-Brood Adult Flea Beetles on Shade Tobi
Dust Applications made at 7-Day Intervals for Control
Nia 9203, 3
Parathion, 1 + Sevin, 10
Bayer 44646, 3
Parathion, 1 + DDT, 10 + Zineb, 6.5
Diazinon, 4 + Endrin, 2 + Zineb, 6.5
Bayer 39007, 5
Diazinon, 4 + Endrin, 2
* Treatments having a common letter are not significantly different at
the 5% level.
Injured Leaves (%) Phytotoxicity Rating
(6 Days After Last Application)* (Avg. Thru Replications)