Efficacy of registered and experimental insecticides for control of European corn borer in Illinois, 1996

John T. Shaw, Michael E. Gray, Kevin L. Steffey and James W. Finger

Summary

Plot Information and Methods

Location

University of Illinois Foundation Shaw Farm, Urbana, Illinois.

Plot Size

Each plot consisted of 4 (30-inches wide) rows by 60 feet long with 4 replications. Treatments were applied to the center 2 rows of each plot leaving 2 untreated rows between each plot.

Experimental Design

A randomized complete block design with 4 replications was utilized. Two untreated control plots were included in each replication and were averaged for the ANOVA.

Planting Date and Agronomic Factors

See Table 10.1.

Weather Information

See Appendix A, Table A.4 and Table A.5

Soil Information

See Appendix B

Manual ECB Infestation

On July 18 and 19, 15 consecutive plants in each of the middle 2 rows of a 4-row plot were infested by placing 2 ECB egg masses (black-head stage) in the whorl of each plant on each date. On the day of infestation, corn plants were in the V9 to V11 development stage (Ritchie et al. 1993, How A Corn Plant Develops, Iowa State University, Cooperative Extension Service.)

Pre-Treatment Population

On August 1, (two days prior to treatment) 20 infested plants were examined for surviving ECB larva. An average of 1.6 larvae per plant was recorded.

Method of Insecticide Application

All insecticide treatments were applied with a modified John Deere 6000 high-clearance vehicle (HCV).

Granular insecticides were metered through Noble units mounted in brackets on the rear of the HCV. The Noble units were driven with electric motors, and the granules were applied over the whorls in a 7-inch band. The banders were similar to banders on conventional row-planters that are used to deliver soil insecticides.

Liquid insecticides were applied with 2 8003 TeeJet flat fan nozzles (1 per row), in a band over the row, with a compressed-air system calibrated to deliver 11 gpa at 15 psi and a speed of 2.5 mph. The height of the nozzles above the whorls was 10 to 12 inches.

Post-Treatment Evaluations

of Injury

On August 26, 10 corn plants (5 from each of the middle 2 rows) that were manually infested were split with a corn knife for evaluation. The number of plants with cavities and the total length of cavities per plant were recorded. The mean percentage of plants with cavities and the mean percentage control (based on the untreated check) were determined for each plot (Table 10.2). The length of stalk tunneling (inches) per plant and the number of cavities per plant were also determined (Table 10.3).

Statistical Analysis

Data were analyzed with the Pesticide Research Manager version 5.0, from Gylling Data Management, Inc.(GDM).

Other Observations

During the mixing process it was noted that the TD2351-04 4FM went into solution quite well, much better than most.

Results and Discussion

The untreated control plots had significantly more cavities per plant and higher percentages of plants with cavities than the insecticide-treated plots. The TD2351-04 4FM treatment was the only treatment that was not significantly different from the untreated control for the mean percentage of plants with cavities and the mean cavity length per plant. For the most part the granular formulations of registered chemicals performed better than liquid formulations, with the 2 Pounce 1.5G and the 2 Dipel (10G and 5SG) treatments being the top performers. The liquid formulations of Decis 180EC, Warrior 1EC, TD2351-01 4FM, Mustang 1.5EC, and TD2344-02 .83E all were found not to be significantly different from the top performing granular treatments.

References Cited

How a Corn Plant Develops, Special Report, No. 48, Iowa State University of Science and Technology, Cooperative Extension Service, Ames, Iowa. Ritche et al. Reprinted June, 1993.

Table 10.1: Agronomic factors for First-generation European corn borer efficacy trial, Urbana, Illinois, 1996

Variables

Urbana

Planting date

June 17

Hybrids

Ill. Foundation Seed

Plant population

26,100

Row spacing

30-inch

Soil condition
(top 2-3 inches)

moist

Previous crop

Corn (1995)

Soil insecticides

none

Herbicides

Dual II 2 pt/A postemergence

Fall tillage

Chisel plow

Spring tillage

Disk, Tilthmaster

Infestation dates

Corn developmental stage

July 18 and July 19
(2 egg masses per plant per date)

V-9 to V-11

Treatment date
Wind
Temperature

August 3
0-5 MPH
75°F

Evaluation date

August 26

Table 10.2 Mean percent of plants with cavities and percentage control after manual infestation for first-generation of European corn borer, Urbana, Illinois 1996¹

Treatment

Rate²

Placement

Mean % of plants with cavities³

% Control⁴

Pounce 1.5G

5 lb prod./acre

band

2.50 g

96

Dipel 10G

5 lb prod./acre

band

7.50 fg

88

Pounce 1.5G

10 lb prod./acre

band

10.00 fg

85

Dipel 5SG

5 lb prod./acre

band

15.00 efg

77

Decis 180EC

0.16

broadcast

17.50 d-g

73

Warrior 1EC

0.025

broadcast

17.50 d-g

73

TD2351-01 4FM

0.75

broadcast

20.00 d-g

69

Mustang 1.5EC

0.047

broadcast

22.50 c-g

65

TD2344-02 .83E

0.03

broadcast

22.50 c-g

65

Scout X-tra .9EC

0.016

broadcast

25.00 c-f

62

Penncap-M 2EC

0.75

broadcast

27.50 c-f

58

Mustang 1.5EC

0.038

broadcast

32.50 b-e

50

TD2351-02 4FM

0.75

broadcast

32.50 b-e

50

ABG-6422 5SG

5 lb prod./acre

band

37.50 bcd

42

M-Peril 4.5G

5 lb prod./acre

band

37.50 bcd

42

MYD-2049 4.5G

5 lb prod./acre

band

42.50 bc

35

TD2351-04 4FM

0.75

broadcast

50.00 ab

23

Control

65.00 a

0

Table 10.3 Mean number of cavities per plant and mean cavity length per plant (inches) after manual inoculation of first-generation European corn borers, Urbana, Illinois 1996¹

Treatment

Rate²

Placement

Mean number of cavities per plant³

Mean cavity length per plant (in)³

Pounce 1.5G

5 lb prod./acre

band

0.03 h

0.01 e

Dipel 10G

5 lb prod./acre

band

0.08 gh

0.16 de

Pounce 1.5G

10 lb prod./acre

band

0.10 fgh

0.14 de

Dipel 5SG

5 lb prod./acre

band

0.15 e-h

0.13 de

Decis 180EC

0.16

broadcast

0.20 d-h

0.14 de

Warrior 1EC

0.025

broadcast

0.20 d-h

0.25 de

TD2351-01 4FM

0.75

broadcast

0.25 d-h

0.35 cde

Mustang 1.5EC

0.047

broadcast

0.28 c-h

0.33 cde

TD2344-02 .83E

0.03

broadcast

0.30 c-h

0.43 cde

Scout X-tra .9EC

0.016

broadcast

0.32 c-h

0.29 de

Mustang 1.5EC

0.038

broadcast

0.35 c-g

0.39 cde

Penncap-M 2EC

0.75

broadcast

0.40 c-f

0.62 cd

M-Peril 4.5G

5 lb prod./acre

band

0.43 cde

0.53 cd

ABG-6422 5SG

5 lb prod./acre

band

0.43 cde

0.62 cd

TD2351-02 4FM

0.75

broadcast

0.48 bcd

0.57 cd

MYD-2049 4.5G

5 lb prod./acre

band

0.57 bc

0.80 bc

TD2351-04 4FM

0.75

broadcast

0.75 b

0.90 ab

Control

1.23 a

1.45 a

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