2002 Corn Rootworm Insecticide Evaluation, Mead, Nebraska

2002 CORN ROOTWORM SOIL
INSECTICIDE EVALUATION¹

Final Report

University of Nebraska
Agricultural Research and Development Center
Mead, Nebraska

Lance J. Meinke, Jim Brown, Jenny Stebbing,
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 - Agronomic Background Information - Entomology

Experimental Design Environmental Conditions at Planting

Rainfall and Irrigation Experimental Compounds Tested
Root Damage Evaluations

Background Information - Agronomic

Hybrid: Pioneer 33G26

Row Spacing: 30 inches

Planting Date: 3 May 2002

Planter: Kinze model 2100, 4 row cone

Planting Depth: 2 inches

Application Equipment: Granular insecticides
Planting: planter mounted cone-belt system

Liquid insecticides
Planter mounted CO2 pressurized sprayer
Field Preparation: Spring 2002 - disked and harrowed

Herbicides Applied: 3 May 2002: Bicep II Magnum, 2.0 qt/A, pre emerge
31 May 2002: 1.0 oz Permit and 0.5 oz Accent / A

Fertilizer Applied: 150 lb. N/A applied as NH3, 5 April 2002

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: There were no significant differences (P > 0.05) among treatment stand count means, or among number of abnormal plants per treatment at V2-3 growth stage (Hanway 1997). Because there was a strong trend toward plant stand differences among treatments (P = 0.06) stands ą SEM are presented for each treatment in Table 1. The overall mean number of plants/33.5' ą SEM = 47.0 ą 0.3.

Insecticide History: Insecticide free: 1993, 1997, 1999, 2001
Multiclass soil insecticide trials: 1994-1996, 1998, 2000

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 - 3 June 2002 (predominantly western corn rootworm).

Root Evaluation: 1-6 (Hills and Peters 1971) 0-3 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: 16 July 2002

Background Information - Experimental Design

Design: Randomized complete block design
Replicated four times
Single row treatments

Row Length: 33.5 feet

Statistical Analysis: Plant Stands, Root Ratings: Standard ANOVA procedures; LSD test was used for mean separation where statistical differences (P = 0.05) occurred.

Background Information - Environmental

Conditions at planting:
Air temperature: 23°C

Wind speed: 15-20 mph at 5 ft height

Wind direction: South

Soil temperature 2" depth: 21°C

Soil temperature surface: 28°C

Soil moisture,0-3" depth: 18.5 % water (gravimetric method)

% cloud cover: clear, 0 % cloud cover

% relative humidity: not recorded

Residue on surface: 30% of soil surface covered with crop residue; soil very moist, somewhat cloddy

Background Information - Rainfall and Irrigation

April May June July

08 0.04 inch 01 0.08 inch 10 0.20 inch 06 0.51 inch

11 0.24 inch 06 0.20 inch 11 0.04 inch 07 0.24 inch

16 0.39 inch 10 0.04 inch 12 0.28 inch 10 0.12 inch

20 0.35 inch 11 1.14 inches 21 0.08

21 0.04 inch 17 0.04 inch 22 0.24 inch

22 0.08 inch 22 0.12 inch 26 0.24

24 0.04 inch 23 0.04

27 1.61 inches 24 0.67 inch

26 0.35 inch

28 0.28

Total 2.79 inches Total 2.96 inches Total 0.52 inches Total 1.43 inches

Irrigation (through July 2002):

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

June 25 1.0 inch July 5 1.5 inches

28 2.5 inches 26 2.0 inches

Experimental Formulations/Applications Evaluated - 2002

Compound Company

Leverage 2.7 SE Bayer

HM0117 1.15 G Helena

HM2042B Helena

Fortress 3.5 G AMVAC

Root Damage Evaluations

Table 1. 2002 Corn Rootworm Soil Insecticide Experiment 1.
University of Nebraska Agricultural Research and Development Center, near Mead, Ne

Root Damage Evaluation

Insecticide Rate/Placement^a Mean Root Damage Rating^b Plant Stand

(1 - 6 scale) (0 - 3 scale) Per 33.5 ft row
± SEM

Leverage 2.7SE see footnote c 2.00a 0.06a 49.8± 1.1

Aztec 4.67G 0.14 I smartbox appl. 2.30ab 0.09a 48.5± 0.6

Aztec 2.1G 0.141 TB 2.55a-c 0.21a 47.5± 1.7

Capture 2EC see footnote d 2.60a-c 0.26ab 48.3± 0.9

Regent 4SC see footnote e 2.70a-d 0.44a-c 48.5± 0.9

Aztec 4.67G 0.14 TB smartbox appl. 2.75a-d 0.25ab 46.0± 1.8

Lorsban 15G 1.2 TB 2.80a-d 0.44a-c 47.5± 1.2

Force 3G 0.12 TB 2.80a-d 0.43a-c 47.8± 1.2

Fortress 3.5G 0.18 I smartbox appl. 2.90a-e 0.46a-c 47.3± 0.9

Counter 20CR 1.2 TB 3.15a-e 0.72a-c 44.0± 2.0

Fortress 5G 0.18 I smartbox appl. 3.20a-e 0.65a-c 50.3± 0.9

HM2042B see footnote f 3.30a-f 0.68a-c 47.5± 1.4

Counter 20CR 1.2 I 3.40b-f 0.98a-d 47.8± 0.9

Lorsban 15G 1.2 I 3.45 b-f 0.89a-d 45.5± 1.2

Fortress 2.5G 0.18 I 3.55b-f 1.07a-e 45.5± 1.3

HM0117 1.15G 0.068 I 3.65c-f 1.02a-d 46.8± 1.5

HM0117 1.15G 0.09 TB 4.00d-g 1.31b-e 45.3± 2.0

HM0117 1.15G 0.09 I 4.00d-g 1.36c-e 48.5± 0.5

HM0117 1.15G 0.068 TB 4.15e-g 1.48c-e 46.0± 1.1

Thimet 20G 1.2 TB 4.15e-g 1.40c-e 45.8± 0.9

Untreated 4.60fg 1.82de 44.8± 0.9

Untreated 5.10g 2.15e 45.0± 1.8

^a placement:
TB = t-Band, 7-inch band placed over the open seed furrow;
I = placed in the open seed furrow;

^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 Leverage 2.7 SE rate: 1.68 oz ai/1000 ft row; volume: 5 gallons water/A, TB application.
^d Capture 2EC rate: 0.075 oz ai/1000 ft row; volume: 5 gallons water/A, TB application.
^e Regent 4SC rate: 0.13 lb ai/A; volume: 4 gallons water/A through microtube into open seed furrow.
^f HM2042B rate: 0.34 oz formulation/1000 ft row; volume: 2 gallons water/A through microtube into open seed furrow.