2006 CORN ROOTWORM EFFICACY AND YIELD TRIAL

 YIELDGARD ROOTWORM COMPARISON TO SOIL INSECTICIDES/SEED TREATMENTS1



Final Report




University of Nebraska

Agricultural Research and Development Center

Mead, Nebraska






Lance J. Meinke, Jim Brown,

 Laura Campbell, Bill McCormick


Department of Entomology

University of Nebraska

Lincoln, Nebraska 68583-0816

 








1 The data presented in this report are not to be released to the public without the written

   permission of the Department of Entomology, University of Nebraska, Lincoln, Nebraska.

 

Background information pertaining to the experiment conducted at the ARDC, near Mead, Nebraska during 2006.

 

 

 

Agronomic

 

            Hybrids:                                    DKC 60-13, DKC 60-17, DKC 60-18

            Row Spacing:                           30 inches

            Planting Date:                           20 April 2006

            Planter:                                     Kinze model 2100, 4 row cone

            Planting Depth:                         2 inches

            Application Equipment:            Granular insecticide

                                                              Planting: planter mounted cone-belt system

                                                            Liquid insecticide

                                                              Planter mounted CO2 pressurized sprayer

            Field Preparation:                    10 March 2006 - chopped and disked, 18 April 2006 - disked

            Herbicides Applied:                 28 April 2006: Cintch ATZ, 2.6 qt/A, pre emerge

                                                              5 June 2006: 1.0 oz/A SPIRIT

            Fertilizer Applied:                    150 lb. N/A applied as NH3, 13 April 2006 

            Previous Crop:                        Continuous corn (trap crop)

 

            Soil Information: 

                  Type:                                  Silty clay loam 

                  Ph:                                              6.4 

                  CEC:                                        29.4                                 

                  % organic matter:                        2.8 

                  % clay:                                     29.05 

                  % silt:                                       66.67                               

                  % sand:                                      4.28 

 

 

            Insecticide History:                   Insecticide free: 1999, 2001, 2003, 2005

                                                            Multiclass soil insecticide trials: 1998, 2000, 2002, 2004

                                                                                                                                                                                                      

Entomological

 

            Species present:                         Northern corn rootworm, Diabrotica barberi Smith and Lawrence, and western corn rootworm, D. virgifera virgifera LeConte. Initial rootworm egg hatch occurred between 27-29 May 2006 (predominantly western corn rootworm).

 

            Root Evaluation:                        0-3 root rating scale (Oleson et al. 2005) was used to evaluate larval corn rootworm damage in each treatment. Ten roots per replication were evaluated in each treatment.

 

            Root Evaluation Date:                20 July 2006

 

 

Experimental Design

 

            Design:                                     Randomized complete block design

                                                                    Replicated four times (except DKC 60-13 treatment: only 3 replications)

                                                                    Four-row treatments

 

            Row Length:                             60 feet

 

            Statistical Analysis:                   Root ratings, final stand, lodging, yields: Used SAS Mixed Procedure; Protected LSD test was used for mean separation (P ≤ 0.05) .

 

 

Environmental

 

 

            Conditions at planting:

 

                  Air temperature:                               18°C

                  Wind speed:                                     15 mph at 5 ft height

                  Wind direction:                                 N - NW

                  Soil temperature 2" depth:                19°C

                  Soil temperature surface:                  23°C

                  Soil moisture, 0-3" depth:                 not recorded

                  % cloud cover:                                60 % cloud cover

                  % relative humidity:                          not recorded

                  Residue on surface:                          40% of soil surface covered with crop residue; soil moist, some clods on surface

 

 

Rainfall

 

April    01  0.24 inches

            02  0.40

            06  0.91

            07  0.01

            15  0.12

            24  0.30

            25  0.23

            28  1.45

            29  0.30

April    30  0.17

Total         4.13

 

May     02  0.03 inches

            03  0.06

            08  0.35

            11  0.01  

            23  0.64

            26  0.04 

May     27  0.06 

Total         1.19

 

June     04  0.32 inches 

            16  0.60

            17  0.90

            24  0.34

            25  0.10

Total         1.94

 

July      02  0.16 inches

            08  0.42

            10  0.40

            13  1.65

            21  0.62

Total         3.25

 

Aug      01  0.13 inches

            02  0.02

            05  0.21

            06  0.72

07  0.50

            08  2.16

            10  0.13

            16  0.77

17  0.11

            18  0.19

            27  0.34

            28  0.01

Total         5.29

            

 

 

 

Irrigation (through August 2006):

 

Sprinkler irrigation was applied as needed throughout the season.

 

June    01  1.00 inches                                       August 04 1.50 inches

          15  1.00                                     

          30  2.00

 

July     07 1.00 inches

          26 1.25

 

             

 

 

 

 

 


Table 1. 2006 Corn Rootworm Soil Insecticide / Neonicotinoid

Seed Treatment Efficacy and Yield Experiment

 

University of Nebraska Agricultural Research and Development Center, near Mead, NE

 

Root Damage Rating, Final Stand, Percentage Lodging + SE

 

 

 

TreatmentTreatment Rate1Mean Root Rating 2
0 - 3 Scale		Final3
Stand		Percentage4
Lodging
MON 863 DKC 60-13 plus Poncho
Cry 3Bb1 (YieldGard Rootworm)		Clothianidin 0.25 mg ai/seed, ST0.04 + 0.01 a149.3 + 8.2 a0.0 + 0.0a
DKC 60-18 plus Poncho 250
Cry3Bb1, Cry1Ab (YieldGard Plus)		Clothianidin 0.25 mg ai/seed0.05 + 0.01a142.5 + 1.7 a2.2 + 1.4a
Isoline DKC 60-17 plus Poncho 1250
and Aztec 2.1G		Clothianidin 1.25 mg ai/seed, ST
Aztec: 0.141 oz ai/ 1000 row-ft, TB		0.18 + 0.03 a146.8 + 4.0 a0.0 + 0.0 a
Isoline DKC 60-17 plus Poncho 250
and Aztec 2.1G		Clothianidin 0.25 mg ai/seed, ST
Aztec: 0.141 oz ai/ 1000 row-ft, TB		0.24 + 0.03 a147.3 + 2.7 a0.0 + 0.0 a
Isoline DKC 60-17 plus Aztec 2.1GAztec: 0.141oz ai / 1000 row-ft, TB0.38 + 0.14 ab145.5 + 3.1 a1.8 + 1.1 a
Isoline DKC 60-17 plus Poncho 1250Clothianidin 1.25 mg ai/seed, ST0.71 + 0.22 bc142.0 + 6.0 a2.9 + 1.7 a
Isoline DKC 60-17 plus Cruiser 5 FSThiamethoxam 1.25 mg ai/seed, ST0.86 + 0.28 c142.3 + 3.3 a13.2 + 13.2 a
Isoline DKC 60-17 plus Poncho 250Clothianidin 0.25 mg ai/seed, ST1.27 + 0.14 d141.8 + 3.4 a7.7 + 2.6 a
Isoline DKC 60-17 1.39 + 0.09 d152.5 + 1.3 a8.3 + 3.8 a

             

 

Planting date: 20 April 2006; Plot size: four rows x 60 ft per treatment per replication, 4 replications; means within columns followed by the same letter are not significantly different (P > 0.05, Fishers Protected LSD Test).

 

1 ST=seed treatment, TB=T-band (7 inch band placed over open seed furrow)

2 Root evaluation date: 20 July 2006, rated 10 roots from two outside rows per treatment per replication using 0-3 node injury scale (Oleson et al. 2005)

3 Final stand = number of plants per 100 ft harvested in two center rows of each plot, stands recorded during October 2006 during harvest

4 Percentage lodging = proportion of final stand leaning >45 degree angle x 100

 

 

Table 2. 2006 Corn Rootworm Soil Insecticide / Neonicotinoid

Seed Treatment Efficacy and Yield Experiment

 

University of Nebraska Agricultural Research and Development Center, near Mead, NE

 

Mean Root Damage Rating and Yield + SE

 

 

TreatmentTreatment Rate 1Mean Root Rating 2
(0 - 3 scale)		Bulk Yield 3
(bushels per acre)
MON 863 DKC 60-13 plus Poncho
Cry 3Bb1 (YieldGard Rootworm)		Clothianidin 0.25 mg ai/seed, ST0.04 + 0.01 a193.3 + 5.4 a
DKC 60-18 plus Poncho 250
Cry3Bb1, Cry1Ab (YieldGard Plus)		Clothianidin 0.25 mg ai/seed0.05 + 0.01a196.5 + 4.9a
Isoline DKC 60-17 plus Poncho 1250
and Aztec 2.1G		Clothianidin 1.25 mg ai/seed, ST
Aztec: 0.141 oz ai/ 1000 row-ft, TB		0.18 + 0.03 a178.2 + 13.9 a
Isoline DKC 60-17 plus Poncho 250
and Aztec 2.1G		Clothianidin 0.25 mg ai/seed, ST
Aztec: 0.141 oz ai/ 1000 row-ft, TB		0.24 + 0.03 a191.8 + 4.7 a
Isoline DKC 60-17 plus Aztec 2.1GAztec: 0.141oz ai / 1000 row-ft, TB0.38 + 0.14 ab192.3 + 8.9 a
Isoline DKC 60-17 plus Poncho 1250Clothianidin 1.25 mg ai/seed, ST0.71 + 0.22 bc183.2 + 4.2 a
Isoline DKC 60-17 plus Cruiser 5 FSThiamethoxam 1.25 mg ai/seed, ST0.86 + 0.28 c179.5 + 12.7 a
Isoline DKC 60-17 plus Poncho 250Clothianidin 0.25 mg ai/seed, ST 1.27 + 0.14 d171.1 + 4.8 a
Isoline DKC 60-17 1.39 + 0.09 d180.0 + 7.5 a

 

             

 

Planting date: 20 April 2006; Plot size: four rows x 60 ft per treatment per replication, 4 replications; means within columns followed by the same letter are not significantly different (P > 0.05, Fishers Protected LSD Test).

 

1 ST=seed treatment, TB=T-band (7 inch band placed over open seed furrow)

2 Root evaluation date: 20 July 2006, rated 10 roots from two outside rows per treatment per replication using 0-3 node injury scale (Oleson et al. 2005)

3 Bulk yields: hand harvested and shelled middle 50 ft of the two inside rows / plot during October 2006, presented as bushels of corn @ 15.5% moisture