2003 CORN ROOTWORM SOIL
INSECTICIDE EVALUATION1

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 - AgronomicBackground Information - Entomology
Experimental DesignEnvironmental Conditions at Planting
Rainfall and Irrigation
Root Damage Evaluations

Background Information - Agronomic

Hybrid: Pioneer 33G26
Row Spacing: 30 inches
Planting Date: 28 April 2003
Planter: Kinze model 2100, 4 row cone
Planting Depth: 2 inches
Application Equipment: Granular insecticides
Planting: planter mounted cone-belt system or Smartbox system
 Liquid insecticides
Planter mounted CO2 pressurized sprayer
Field Preparation: 16 April 2003 - deep chiseled and disked
28 April 2003 - field cultivated
Herbicides Applied: 28 April 2003: Bicep II Magnum, 2.5 qt/A, pre emerge
9 April 2003: 4 oz Distinct and 0.67 oz Accent / A
Fertilizer Applied: 150 lb. N/A applied as NH3, 3 April 2003
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/ Phytotoxicity: Hard rains after planting and crusting problems during germination resulted in a sub-optimal stand across treatments. A statistical analysis of stand counts among treatments was not conducted because of potential confounding effects of environment and treatment on stand. The overall mean number of plants/33.5' ± SEM = 34.4 ± 4.9.
Insecticide History: Insecticide free: 1994 - 1996, 1998, 2000, 2002
Multiclass soil insecticide trials: 1993, 1997, 1999, 2001

Background Information - 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 31 May - 2 June 2003 (predominantly western corn rootworm).
Root Evaluation: 1-6 (Hills and Peters 1971) and 0-3 (J. Oleson, Iowa State University) root rating scales were used to evaluate larval corn rootworm damage in each treatment. Five roots were evaluated in each treatment and replication.
Root Evaluation Date: 22 July 2003

Background Information - Experimental Design

Design: Randomized complete block design
Replicated four times
Single row treatments
Row Length: 33.5 feet
Statistical Analysis: Root Ratings: Used SAS Mixed Procedure; Protected LSD test was used for mean separation (P less than or equal to 0.05)

Background Information - Environmental

Conditions at planting:
Air temperature: 24°C
Wind speed: 10 mph at 5 ft height
Wind direction: East
Soil temperature 2" depth: 19°C
Soil temperature surface: 29°C
Soil moisture,0-3" depth: 15.3 % water (gravimetric method)
% cloud cover: clear, 0 % cloud cover
% relative humidity: not recorded
Residue on surface: 40% of soil surface covered with crop residue; soil moist, somewhat cloddy

Background Information - Rainfall and Irrigation

April     May     June     July    
  04 0.32 inch   04 2.05 inch   01 0.20 inch   31 0.20 inch
  06 0.66 inch   05 0.08 inch   02 0.28 inch      
  18 0.04 inch   06 0.32 inch   05 0.39 inch      
  19 0.04 inch   08 1.06 inches   06 0.04 inch      
  21 0.04 inch   10 0.20 inch   07 0.51 inch      
  23 0.20 inch   22 0.04 inch   09 0.24 inch      
  24 0.04 inch   24 0.20 inch   12 0.43 inch      
  28 0.08 inches         18 1.38 inches      
  29 0.95 inch         22 0.04 inch      
  30 0.12 inch                  
  Total 2.49 inches   Total 4.93 inches   Total 3.51 inches   Total 0.20 inches

Irrigation (through July 2003):

Sprinkler irrigation was applied periodically between planting and root damage evaluation.

July32.5 inches
 210.5 inches
 252.0 inches

Root Damage Evaluations

Table 1. 2003 Corn Rootworm Soil Insecticide Experiment 1.
University of Nebraska Agricultural Research and Development Center, near Mead, Ne

Root Damage Evaluation

Insecticide Rate/Placementa Mean Root Damage Ratingb
    (1 - 6 scale) (0 - 3 scale)
Regent 4 SC see footnote c 2.30a 0.06a
Regent 4 SC see footnote d 2.40ab 0.11a
Fortress 5G 0.22 I, smartbox appl. 2.50ab 0.09a
Aztec 4.67G 0.137 I, smartbox appl. 2.55ab 0.17a
Aztec 4.67G 0.137 TB, smartbox appl. 2.65ab 0.17a
Capture 2EC see footnote e 2.65ab 0.17a
Capture 2EC see footnote f 2.70ab 0.14a
Force 3G 0.12 TB 2.70ab 0.14a
Aztec 2.1G 0.141 TB 2.70ab 0.18a
Poncho 600 ST, 1.25 mg ai/seed 2.75ab 0.28ab
Fortress 5G 0.18 I, smartbox appl. 2.75ab 0.34ab
Thimet 20G 1.2 TB 2.75ab 0.31ab
Counter 20CR 1.2 TB 2.85abc 0.16a
Lorsban 15G 1.2 I 2.85abc 0.24a
Cruiser 5FS ST, 1.25 mg ai/seed 2.95abc 0.48ab
Lorsban 15G 1.2 TB 3.05 bc 0.40ab
Untreated   3.55 cd 0.80 bc
Untreated   4.00 d 1.21 c
a placement:
TB = T-Band, 7-inch band placed over the open seed furrow;
I = placed in the open seed furrow;
ST = seed treatment

b Root rating scales used: 1 - 6 scale (Hills and Peters 1971); 0 - 3 scale (J. Oleson, Iowa State University); Within columns, mean root rating values followed by the same letter are not significantly different from each other (Fisher's protected LSD test @ 0.05 significance level).

c Regent 4 SC: rate:0.13 lb ai/A; volume: 4 gallons water/A through microtube into open seed furrow.

d Regent 4 SC: rate:0.13 lb ai/A; volume: 1 gallon water/A, through microtube into open seed furrow.

e Capture 2EC: rate:0.0875 oz ai/1000': volume: 5 gallons water/A, TB application.

f Capture 2EC: rate 0.075 oz ai/1000': volume: 5 gallons water/A, TB application.