2006 CORN ROOTWORM EFFICACY TRIAL:

 HERCULEX RW™ COMPARISON TO SOIL INSECTICIDES AND SEED TREATMENT1



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:                                    Pioneer® Brand Hybrids 34A15, 34A19

            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 

 

 

            Plant Population:                       There were no significant differences (P > 0.05) among treatment stand count means at V3 growth stage (Hanway 1997). The overall mean number of plants per 33.5 ft + SEM = 45.7 + 0.5

 

            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. Five roots per replication were evaluated in each treatment.

 

            Root Evaluation Date:               12 July 2006

 

 

Experimental Design

 

            Design:                                    Randomized complete block design

                                                                    Replicated four times

                                                                    Four-row treatments

 

            Row Length:                            33.5 feet

 

            Statistical Analysis:                  Root ratings, stand: 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

 

April010.24 inches
 020.40
 060.91
 070.01
 150.12
 240.30
 250.23
 281.45
 290.30
 300.17
AprilTotal4.13 inches

 

May020.03 inches
 030.06
 080.35
 110.01
 230.64
 260.04
 270.06
MayTotal1.19 inches

 

June040.32 inches
 160.60
 170.90
 240.34
 250.10
JuneTotal1.94 inches

 

July020.16 inches
 080.42
 100.40
 131.65
 210.62
JulyTotal3.25 inches

 

August010.13 inches
 020.02
 050.21
 060.72
 070.50
 082.16
 100.13
 160.77
 170.11
 180.19
 270.34
 280.01
AugustTotal5.29 inches

            


 

 

 

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 Experiment 4.

Pioneer Hi-Bred Herculex Rootworm™ Corn Rootworm Efficacy Study

 

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

 

Root Damage Evaluation

 

 

 

TreatmentTreatment Rate1Mean Root Rating 2
Pioneer ® Brand Hybrid 34A19
Cry 34/35 plus Poncho®250
(Herculex Rootworm®)		Clothianidin 0.25 mg ai per seed, ST0.05 + 0.01 a
Pioneer® Brand Hybrid 34A15
plus Regent® 4SC		0.13 lb ai per acre, I, 5 gpa, MT0.18 + 0.05 a
Pioneer® Brand Hybrid 34A15
plus Aztec® 2.1G		0.141 oz ai per 1000 row-ft, TB0.33 + 0.10 ab
Pioneer® Brand Hybrid 34A15
plus Poncho® 1250		Clothianidin 1.25 mg ai per seed, ST0.71 + 0.15 b
Pioneer® Brand Hybrid 34A15 1.80 + 0.22 c

 

             

 

Planting date: 20 April 2006; Plot size: four rows x 33.5 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 I= placed in the open seed furrow, ST=seed treatment, TB=T-band (7 inch band placed over open seed furrow),

  MT=microtube application

2 Root evaluation date: 12 July 2006, rated 5 roots from two inside rows per treatment per replication using 0-3

  node injury scale (Oleson et al. 2005)