Efficacy of Soil Insecticides for the Control of Wireworms, White Grubs, and Grape Colaspis in Field Corn, Logan County, Illinois, 2000
John T. Shaw, Michael E. Gray, and Kevin L. Steffey

Summary

Plot Information and Methods

Cooperator and Location

The field used for this insecticide efficacy trial was obtained with the help of Mr. Rick Reed of AG Land FS, Mt. Pulaski, Logan County, Illinois.

Plot Size

Each treatment was applied to a single row (30-ft long) in each of four replicates.

Experimental Design

A randomized complete block with four replications was utilized as the experimental design. Two untreated control plots were included within each replication. Data collected from the untreated control plots were averaged for the analysis of variance (ANOVA).

Planting Dates and Agronomic Factors

See Table 3.1.

Pre-treatment Population

In late March of 2000, bait stations were established at the experimental site and later revealed an infestation of wireworm larvae. Annual white grubs also were found in the bait stations when they were examined in April.

Method of Application for Granules at Planting Time

Granular insecticides were applied at planting and metered through computer controlled SmartBox (SBX) granular applicators or NobleŽ units mounted on each row of an ALMACOŽ four-row precision planter. Insecticides were applied in-furrow or in a 7-inch band ahead of the firming wheels on the planter. Spring tines mounted behind each planter unit were used to incorporate the insecticide. All rates are specified as lb. (AI)/acre based on a 30-inch row spacing.

Method of Application for Liquids at Planting Time

Regent 4SC and Force WF2829 30CS were delivered in-furrow at planting through microtubes calibrated to deliver 2.1 gpa at 30 psi at a speed of 3.0 mph. Capture 2EC, Force WF2829 30CS, and Warrior T 1CS were applied through a single 8003 (flat fan) nozzle in-furrow or as a band and calibrated to deliver 4.9 gpa at 21 psi at a speed of 3.0 mph.

Seed Treatments

All seed treatments were applied to NK 58D-1 seed by the respective company. This same seed variety also was utilized for all granular and liquid treatments.

Post-Treatment Evaluations

On May 23 insect abundance was estimated by removing a trench of soil 39.4 in. (1 meter, length) X 4 in. (width) X 4 in. (depth) and counting the number of insects found. The number of live plants, grape colaspis larvae, white grubs, and wireworms were determined for each trench. Plants were in the V2 to V3 leaf stage (Ritchie et al. 1993).

Phytotoxicity

Symptoms of phytotoxicity were not observed for any of the insecticide treatments.

Statistical Analysis

Data were analyzed with the Agriculture Research Manager (ARM) version 6.1.6, from Gylling Data Management, Inc.(GDM). Means were separated by Duncan's New Multiple Range Test (P=0.05).

Results and Discussion

Despite the presence of numerous wireworms in bait stations earlier in the spring, very few larvae were discovered in this experimental trial (Table 3.2). Even though significantly fewer live wireworms were observed in every insecticide treated row compared with the control, less than two wireworms were found per meter of row in the check plots. No significant differences in the number of dead wireworms per meter of row were observed among any of the treatments, including the control plots.

Significantly fewer grape colaspis larvae were found in most insecticide-treated rows with only the following exceptions (Table 3.3): Capture 2EC (band, 0.04 lb. (AI)/acre), EX-1 and EX-2 seed treatments, Maxim XL 2.7FS + Adage 5FS seed treatment, Force 2829 30CS, and Gaucho 1.3 mg per seed.

Significantly fewer white grubs were found in all insecticide treated rows compared with the control plots (Table 3.3). However, overall white grub pressure was minimal in this experiment.

References Cited

Ritchie, S.W., J. J. Hanway, and G.O. Benson. 1993. How a corn plant develops. Special Report No. 48, Iowa State University of Science and Technology, Cooperative Extension Service, Ames.

Table 3.1 Agronomic factors and evaluation dates for the grape colaspis efficacy trial in Menard County, Illinois, 2000.

Variables

Logan County

Planting date

May 3, 2000

Hybrid

NK58 D-1

Plant population

28,500 seeds per acre

Row spacing

30 inches

Soil condition (top 2-3 inches)

Moist

Soil temperature (4-inch level)

62°F

Air temperature

73°F

Wind

0-5 mph

Previous crop

Soybeans

Soil insecticides

None

Fall tillage

None

Spring tillage

Disc once

Evaluation dates:

May 23, 2000

Table 3.2 Mean number of live and dead wireworms in one meter of row, Logan County, Illinois, 2000.

Treatment

Rate¹

Placement

Number of wireworms²

Live

Dead

Capture 2EC

0.040

Furrow

0.00

b

0.75

a

Capture 2EC

0.080

Furrow

0.50

b

0.75

a

Capture 2EC

0.040

Band

0.25

b

0.25

a

Capture 2EC

0.080

Band

0.50

b

0.00

a

Force 3G

0.150

Furrow

0.00

b

0.50

a

Force 3G

0.130

Band

0.00

b

0.50

a

EX-1

seed treatment

0.25

b

0.00

a

EX-2

seed treatment

1.00

b

0.25

a

EX-3

seed treatment

0.25

b

0.00

a

Counter 20CR

1.300

Furrow

0.25

b

0.75

a

Aztec 2.1BD

0.150

Band

0.50

b

0.50

a

Maxim XL 2.7FS

0.060

seed treatment

0.25

b

0.00

a

Maxim XL 2.7FS
+ Adage 5FS

0.060
0.800

seed treatment

0.75

b

0.25

a

Maxim XL 2.7FS
+ Kernel Guard Supreme

0.060
1.800

seed treatment

0.25

b

0.00

a

Regent 4SC

0.130

Microtube

0.50

b

0.25

a

Force 2829 30CS

0.120

Band

0.25

b

0.25

a

Warrior T 1CS

0.030

Band

0.25

b

0.25

a

Lorsban 15G

1.300

Band

0.25

b

1.00

a

Lorsban 15G

1.300

Furrow

0.00

b

0.75

a

ProShield

seed treatment

0.25

b

0.50

a

Gaucho

1.300

seed treatment

0.25

b

0.25

a

Fortress 5G

0.160

Furrow

0.00

b

0.00

a

Control

1.88

a

0.00

a

¹ Rates are specified as lb (AI)/acre.
² Means in a column followed by the same letter are not significantly different (P=0.05; Duncan's New MRT).

Table 3.3 Mean number of grape colaspis and grubs in one meter of row for the wireworm efficacy trial, Logan County, Illinois, 2000

Treatment

Rate¹

Placement

Number of live larvae²

Grape
Colapsis

Grubs

Capture 2EC

0.040

Furrow

0.00

c

0.00

b

Capture 2EC

0.080

Furrow

0.75

c

0.00

b

Capture 2EC

0.040

Band

1.25

abc

0.50

b

Capture 2EC

0.080

Band

0.50

c

0.25

b

Force 3G

0.150

Furrow

0.50

c

0.25

b

Force 3G

0.130

Band

0.50

c

0.00

b

EX-1

seed treatment

3.00

ab

0.25

b

EX-2

seed treatment

1.50

abc

0.25

b

EX-3

seed treatment

0.50

c

0.00

b

Counter 20CR

1.300

Furrow

0.00

c

0.00

b

Aztec 2.1BD

0.150

Band

0.50

c

0.00

b

Maxim XL 2.7FS

0.060

seed treatment

0.75

c

0.25

b

Maxim XL 2.7FS
+ Adage 5FS

0.060
0.800

seed treatment

1.50

abc

0.25

b

Maxim XL 2.7FS
+ Kernel Guard Supreme

0.060
1.800

seed treatment

1.00

bc

0.00

b

Regent 4SC

0.130

Microtube

0.25

c

0.00

b

Force 2829 30CS

0.120

Band

1.50

abc

0.00

b

Warrior T 1CS

0.030

Band

1.00

bc

0.00

b

Lorsban 15G

1.300

Band

1.00

bc

0.50

b

Lorsban 15G

1.300

Furrow

0.25

c

0.50

b

ProShield

seed treatment

0.00

c

0.00

b

Gaucho

1.300

seed treatment

1.25

abc

0.75

b

Fortress 5G

0.160

Furrow

1.00

bc

0.25

b

Control

3.13

a

1.75

a

¹ Rates are specified as lb (AI)/acre, except for seed treatments which are expressed as mg/seed.
² Means in a column followed by the same letter are not significantly different (P=0.05; Duncan's New MRT).

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