Everglades Station Mimeo Rpt. EES64-19
CONTROL OF SOIL INSECTS AND SWEET CORN INSECTS/ '
Enmett D. Harris, Jr. 2/
The results shown in this report are not intended as insect control
recommendations. One should refer to Florida Agriculture Extension
Circular 1930 or consult the County Agent, Experiment Station Entomologist,
or the insecticide label for insect control recommendations.
SOIL INSECT CONTROL
Experiment I Screening Test for Southern Potato Wireworm, Conoderus
fall Lane, and Corn Wireworm, Melanotus communis (Gyll), Control.
Insecticides were applied broadcast on October 10, 1963, and immediately
disked into the soil to a depth of about 6 inches. Florigold 107 sweet
corn was planted on October 11.
Insecticide Formulation
Stauffer N-2788 10% gran. 40 Ibs.
Stauffer N-2790 10% gran. 40 lbs.
Thimet 10% granules 40 lbs.
Dibrom (8 lb/gal) E 0.5 pt.
Phosphamidon (4 lb/gal)Spray 1.0 pt.
Untreated --
Live Wireworms/100 plants
Southern
Amount Potato Corn
per Acre Wireworm Wireworm Total
0
0.5
0
5.0
4.0
10.0
5.0
9.5
3.5
7.5
16.0
5.0
5.0
10.0
3.5
12.5
20.0
15.0
Plants/Acre
,000
26
27
29
25-
.27
27
The above figures for wireworm populations were based on observations
on three dates. On October 25, Thimet seemed to be highly effective but
seemed to have lost its effectiveness by November 27.
Experiment II Diazinon and Kepone Formulations and Aldrin Spray for
Wireworm Control. Insecticides were applied broadcast on October 4,
1963, and immediately disked-in to a depth of about 6 inches. Florigold
107 sweet corn was planted on October 11.
(Table on the next page.)
1/ Prepared for presentation at the Annual Vegetable Crops Field Day
held at the Everglades Experiment Station, May 7, 1964.
2/ Associate Entomologist, Everglades Experiment Station, Belle Glade,
Florida.
Wireworms forced to
the soil surface
Insecticide Formulation
4% Kepone on Corimeal
5% Diazinon on Corn Grits
5% Diazinon on Walnut
Shell Gran.
Kepone (3 lb/gal)
Flowable
Diazinon (4 Ib/gal) EC
Aldrin (4 lb/gal) EC
Diazinon EC.- Aldrin EC
Untreated
Amount
per Acre
125 Ibs.
100
100
per 1,000
Southern
Potato
Wireworm
0
2.1
0.7
1.33 gal. 6.2
1.0
1.0
0.5 gal.
each
3.5
5.5
2.1
sq. ft.
Corn
Wire-
worm I
0
7.6
8.3
total
0
O 7
9.7
8.3
3.5 9.7
1.4
1.4
4.8
4.9
6.9
6.9.
Live Wireworms
per 100 plants
southern Corn
Potato Wire-
Wireworm worm Total
0 7.5 7.5
0.8 4.2 5.0
0 8.3 8.3
0 16.7 16.7
0 10.0 10.0
5.0 1o.o 15.0
0 14.2 14.2
0 0 1.7 20.0 21.7
Experiment III Kepone Baits. Baits were applied broadcast on October 10,
1963, and immediately disked-in to a depth of about 6 inches. Florigold 107
sweet corn was planted on October 11.
Insects per.100 Plants
Lbs.
per
Kepone and Bait Acre
4% on Cornmeal
4% on Sugarcane Bagasse
4% on Cornmeal + 5% Molasses
4% on Corn Cob Grits + 5%
Molasses
4% on Cornmeal
4% on Cornmeal + 5% Molasses
2% on Cornmeal
Untreated
100
100
100
100 .
50
50
100
Corn
Wire -
worms
4.6
4.6
7.1
7.1
7.5
9.6
9.2
14.2
Cucumber
Beetle
Grubs
0.8
0.8
1.3
1.7
2.1
2.5
1.7
4.6
Total
5.4
5.4
8.4
8.8
9.6
12.1
10.9
18.8
Plants/
Acre ,000
31.2
29.4
30.5
28.2
29.2
27.3
28.9
26.4
Experiment IV Aldrin, Kepone, and Parathion Combinations for Soil Insect
Control. These insecticides were applied in emulsions at the rate of 4
pounds of total actual toxicant per acre. In 2-way mixtures each insecti-
cide was used at 2 pounds of actual toxicant per acre. In the 3-way mixture
each was used at 1.33 pound. Treatments were applied broadcast on October
4, 1963, and immediately disked into the soil to a :depth of about 6 inches.
Florigold 107 sweet corn was planted on October.11.
(Table on the next page.)
Wireworms forced to
the soil surface per Live Soils Insects
1,000 sq. ft,,, per 100 Plants
Southern Corn Southern Corn Cucumber Plants/
Potato Wire- Potato Wire- Beetle Acre
Insecticides Wireworm wor4 Total Wireworm worm Grubs Total ,000
Parathion 1.7 8.7 10.4 0 6.7 0.4 7.1 27.9
Aldrin 1.0 2.4 3.4 7.1 10.4 0.4 17.9 25.3
Kepone 1.7 1.0 2.7 1.3 11.3 0.8 13.3 23.8
Parathion-Aldrin 110 13.9 14.9 0 8.3 1.3 9.6 27.3
Parathion-Kepone 1.4 3.8 5.2 0 6.7 0 6.7 26.9
Aldrin-Kepone 1.0 0.7 1.7 2.1 6.7 0.4 9.2 25.3
Pth-Ald-Kep 1.0 2.4 3.4 0.4 10.0 0.4 10.8 26.5
Untreated 0 1.4 1.4 5.8 12.1 2.1 20.0 23.8
Experiment V Kepone Bait, Diazinon Bait and Granules, and Parathion
Granules for Control of the Corn Wireworm. Insecticides were applied
broadcast at five pounds actual toxicant per acre on January 16, 1964,
and immediately disked-in to a depth of about 6 inches. Florigold 107
sweet corn was planted on January 30.
Live Corn Percent Plants/
Wireworms/ Damaged Acres
100 Plants Plants ,000
Kepone 4% on Cornmeal 1.4 0.5 25.5
Diazinon on Corn Grits 1.9 0 20.3
Diazinon 57 Walnut Shell Gran. 8.1 5.8 20.9
Parathion 10 Granules 6.7 1.7 21.2
Untreated 8.1 13.9 13.9
Experiment VI Parathion Granules for Wireworm Control. Three parathion
107% granular formulations were each applied broadcast to give 5 pounds of
actual toxicant per acre on January 29, 1964, and immediately disked-in
to a depth of about 6 inches. Florigold 107 sweet corn was planted on
January 30.
Live Wireworm/100 Plants
Southern Percent
Potato Corn Damaged Plants/
Wireworm Wireworm Total Plants Acre,000
Source A 1.0 5.2 6.2 3.1 27.5
Source B "Stabilized" 0.5 2.4 2.9 3.4 28.8
Source B "Unstabilized" 1.0 1.9 2.9 4.9 34.6
Untreated 6.2 3.3 9.5 3.9 31.2
-4-
Experiment VII Post-emergence Insecticide Applications for Corn
Wireworm and Cucumber Beetle Grub Control. Florigold 107 sweet corn
was planted on January 30, 1964. .Insecticides .were applied to the
soil in the row on February 19 and .covered to a depth of about 1 or
2 inches using a hand plow.
Live Insects/100 Plants
Lbs. Corn Cucumber Percent
per Wire- Beetle Damaged
Insecticide Formulation Acre worm Grubs Total Plants
1% Thimet on Soy Feed 100 1.2 6.7 7.9 0.6
1% Thimet on Cracked Corn 100 2.4 5.5 7.9 5.0
1% Thimet on Cornmeal 100 0.6 8.5 9.1 0.7
10% Thimet Granules 10 3.0 3.6 6.6 4.2
10% Thimet Granules 50 2.4 2.4 4.8 2.1
10% Parathion Granules 50 1.2 7.9 9.1 0.6
Untreated -- 4.8 12.7 17.5 .5.0
SUMMARIZATION OF WIREWORM EXPERIMENTS. The southern potato wireworm
is adequately controlled by phosphatic insecticides such as Diazinon and
parathion. However, the corn wireworm is considerably more difficult to
control.
No Wireworm treatment has consistently been as effective as we would
desire. In general, baits and insecticide combinations have shown promise
and will be closely studied in future research.
As mentioned earlier, the data included in this report should not be.
construed as recommendations.
Before using any insecticide on a crop or on land to be planted to a
crop, the grower should be certain that the insecticide is approved for use
on that crop and in the manner that he plans to use it.
-5-
BUDITORM CONTROL ON STREET CORN
Experiment I Parathion, DDT, Toxaphene, Sevin and Two-Insecticide
Combinations for Budworm Control. Florigold 107 sweet corn was planted
on September 10, 1963. Plots were treated equally with a DDT-Toxaphene
mixture twice weekly from September 13 to September 19 for corn stem
weevil control. No more insecticide treatments were made before experimental
applications were begun on October 9. Experimental applications were
made at 100 gallons per acre on October 9 and 16, and at 150 gallons per
acre on October 21 and 24. Nearly all of the budworms encountered were
fall armyworms, Laphygma frugiperda (J. E. Smith). Coth earworms, Heliothis
zea (Boddie), were infrequent.
Pints Percent Budworm
/100 Damaged Plants
Insecticide Formulation Gals.. Oct. 17 Oct.25
Parathion 4 lb/gal Flowable 0.5 37 39
DDT 2 lb/gal EC 4.0 40 50
Toxaphene 8 lb/gal EC 1.5 45 50
Sevin 4 Ib/gal Flowable 2.0 45 59
Parathion-DDT 0.25 2.0 36 36
Parathion-Toxaphene 0.25 0.75 42 47
Parathion-Sevin 0.25 1.0 54 55
DDT-Toxaphene 2.0 0.75 32 31
DDT-Sevin 2.0 1.0 40 55
Toxaphene-Sevin 0.75 1.0 41 64
Untreated-------- 49 68
Under the conditions of the experiment, none of the treatments were
satisfactory. After budworms have become established in the whorl, as in
this experiment, control is more difficult. Also, better control may
have been obtained had one of the insecticides in each combination been
used at recommended strength, or if sprays had been applied twice weekly.
Parathion was the most promising insecticide when used alone. Among
mixtures, parathion-DDT and DDT-toxaphene showed the greatest promise.
Experiment II DDT, Sevin, and DDT-Sevin Combinations for Budworm Control.
Florigold 107 sweet corn was planted on February 7, 1964. All plots were
treated equally with a DDT-toxaphene mixture twice weekly until February 24.
Experimental applications were made twice weekly from February 24 to March 9
and then weekly until April 7. Each spray was applied at 100 gallons per
acre. Only fall armyworms were observed in the whorls. DDT was used as
a 2 pound per gallon emulsifiable concentrate, Sevin as an 80 percent
Sprayable powder.
Insecticide
DDT
DDT Sevin
DDT Sevin
DDT Sevin
Sevin
Untreated
Pound
Act. Txc./Acre
1
1-1
1- 0.5
1.- 0.25
1
-------
Percent Budworm Damaged Plants
Mar. 23 Mar. 30 Apr. 6
7
8
7
11
16
27
In short, DDT was more effective than Sevin
was not increased by the addition of Sevin.
and its effectiveness
Experiment III DDT, Toxaphene, and DDT-Toxaphene Combinations for
Budworm Control. Florigold 107 sweet corn was planted on March 11, 1964.
All plots were treated equally with DDT-Toxaphene sprays on March 16
and 19 for corn stem weevil control. Experimental sprays were applied
twice weekly from March 23 to April 6. Since then, they have been
applied weekly. The application rate has been 100 gallons per acre.
As of April 23, this experiment is still in progress.
Insecticide Formulation
DDT (2 lb/gal) EC
Toxaphene (8 Ib/gal) EC
DDT Toxaphene
DDT Toxaphene
DDT Toxaphene
Untreated
Pints of
Formulation
/100 gals.
4 .
1.5
4 1.5
4 0.75
2 1.5
Percent Budworm
Damaged Plants
April 15 April 21
4
2
8
20
15
26
8
4
S9
29-
So far there seems to be a definite advantage in using DDT-toxaphene
in combination over using either material alone.
Experiment IV DDT, Parathion, and DDT-Parathion Combinations for Budworm
Control. Planting and application procedures are the same as those in
Experiment III.
Insecticide Formulation
DDT (2 lb/gal) EC
Parathion (4 Ib/gal) EC
DDT Parathion
DDT Parathion
DDT Parathion
Untreated
. Pints of
.Formulation
/100 gals.
4
0.5
4 0.5
4 0.25
2 0.5
aain a
Percent Budworm
Damaged Plants
April 15 April 21
To date DDT-parathion combinations seem considerably more effective
than DDI or parathion alone.
Experiment V The Effect of Mineral Oil on Budworm Control with Toxaphene
and DDT Emulsions. Toxaphene (8 lb/gal) EC was used at 1.5 pints per
100 gallons, DDT (2 Ib/gal) EC at 4 pints, and Sun Superior Spray Oil 7-E
at 10 pints. Planting and application procedures are the same as in
Experiment III with the exception that the weekly spray scheduled for
April 14 was omitted in this experiment because some of the plots were
showing mineral oil burn. Weekly sprays were resumed on April 21.
Percent Budworm Damaged Plants
Treatments April 15 April 21
DDT 1 18
DDT Oil 0 1 16
Toxaphene "11 35
Toxaphene Oil 3 24
Untreated 15 28
It seems that the addition of the mineral oil had a greater effect
on toxaphene sprays than on DDT sprays. The plant damage from mineral oil
was very slight to slight but perhaps a strong indication that we are
using it too often or at too high a rate. The poor control obtained on
April 21 was probably caused by too long an interval since the previous
spray.
CONTROL OF EARTORMS ON SIEET CORN
Experiment I Spray Gallonages and Intervals Between Applications for
Earworm Control. Florigold 107 sweet corn that silked on May 6, 1963,
and was harvested on May 24, was sprayed from May 7.until May 23.
One gallon of DDT (2 Ib/gal) EC per acre was applied in 12.5, 25, and
50 gallons of spray per acre at 1-day and at 2-day intervals. In
untreated check plots, 46 percent of the earworms were corn earworms,
Heliothis zea (Boddie), and 54 percent were fall armyworms, Laphygma
frugiperda -(. E. Smith).
Gallons
per Acre Spray Frequency Percent Worm-free Ears
12.5 every day 56
12.5 every other day 42
25 every day 74
25 every other day 56
50 every day 74
50 every other day 58
Untreated
100
-8-
There is a strong indication that our earworm control measures
should be greatly improved or that we should quit planting sweet corn
to be harvested as late as May. Even daily sprays did not adequately
control earworms.. Gallonages per acre of 25 and 50 were about equally
effective but decidedly superior to 12.5.
Experiment II Parathion, DDT, Toxaphene, Sevin and Two-Insecticide
Combinations for Earworm Control. Experimental applications were made
twice weekly from October 28, 1963, to November 14, and were applied
at 50 gallons per acre. The-Florigold 107 sweet corn was harvested
on November 18 and 19.
Insecticide
Formulation
Pints/
50 gals.
/Acre
Percent Percent Percent
Worm-free Corn Fall
Ears Earworm Armyworm
Parathion
DDT
Toxaphene
Sevin
Parathion-DDT
Parathion-Toxaphene
Parathion-Sevin
DDT-Toxaphene
DDT-Sevin
Toxaphene-Sevin
Untreated
With the exception
more effective than the
by itself. However, it
of both insecticides in
treatments in which one
are used at the regular
4 lb/gal Flowable
2 lb/gal EC
8 Ib/gal EC
4 lb/gal Flowable
1
8
3
4
0.5 8
0.5 1.5
0.5 2
4.0 -1.5
4.0 -2.0
1.5 -2.0
------me,
.of DDT-Sevin, no insecticide combination was
most effective of the insecticides when applied
was probably a mistake to half the concentration
the combination. Future experiments will contain
or both of the insecticides in a combination
rate.
EES64-19
400 copies
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