2000 Corn Rootworm Soil Insecticide Trials

University of Nebraska-Lincoln

2000 CORN ROOTWORM SOIL INSECTICIDE EVALUATIONS
AGRICULTURAL RESEARCH AND DEVELOPMENT CENTER
MEAD, NEBRASKA

Lance J. Meinke, Jim Brown, Jenny Stebbing, Bill McCormick
Department of Entomology
University of Nebraska
Lincoln, Nebraska 68583-0816

Background Information - Agronomic	Background Information - Entomology
Experimental Design	Environmental Conditions at Planting
Environmental Conditions: Furadan Applications	Rainfall and Irrigation
Experimental Compounds Tested	Root Damage Evaluations

Background Information -Agronomic


Hybrid:	Pioneer 33G26
Row Spacing:	30 inches
Planting Date	28 April 2000
Planter:	Kinze model 2100, 4 row
Planting Depth:	2 inches
Application Equipment:	Granular Insecticides Planting: Planter mounted cone-belt system Liquid Insecticides CO₂ pressurized sprayer
Field Preparation:	Spring 2000 - disked and harrowed
Herbicides Applied:	4 May 2000: Bicep II Magnum, 2.1 qt./A, pre-emerge
Fertilizer Applied:	150 lb. N/A applied as NH₃ on 4 April 2000
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:	Overall mean number of plants/33.5' ± SEM = 48.4 ± 0.3
Phytotoxicity:	There were no significant differences (P > 0.05) among treatment stand count means or among number of abnormal plants/treatment at V2-3 growth stage (Hanway 1997).
Insecticide History:	Insecticide free: 1991, 1993, 1994, 1997-1999 Multiclass soil insecticide trials: 1990, 1992, 1995-1996

Background Information - Entomology

Species Present:	Northern corn rootworm, Diabrotica barberi Smith and Lawrence, and western corn rootworm, D. virgifera virgifera LeConte. Initial rootworm egg hatch detected 24 May 2000 (predominantly western corn rootworm)
Root Evaluation:	A 1-6 root rating scale (Hills and Peters, 1971) was used to evaluate larval corn rootworm damage in each treatment. Five roots were evaluated in each treatment per replication. (See Nebguide G92-1108-A for rating scale description.)
Root Evaluation Date:	10 July 2000

Experimental Design

Design:	Randomized complete block design Replicated four times Single row treatments except for broadcast Furadan 4F plots which were 3 rows wide
Row Length:	33.5 feet
Statistical Analysis:	Root Ratings: Standard ANOVA procedures, LSD test was used for mean separation where statistical differences (P less than or equal to 0.05) occurred.

Environmental Conditions at Planting

Air Temperature:	17^oC
Wind speed:	5-10 mph at 5 ft. height
Wind direction:	NW
Soil temperature 2" depth:	14.5^oC
Soil temperature surface:	16^oC
Soil moisture, 0-3" depth:	23.5% water (gravimetric method)
% cloud cover:	25%
% relative humidity:	not recorded
Residue on surface:	20% of soil surface covered with crop residue; soil very moist

Environmental Conditions:Furadan applications

Air temperature:	20^oC
Wind speed:	10 mph at 5 ft. height
Wind direction:	N
Soil temperature 2" depth:	25^oC
Soil temperature surface:	26^oC
Soil moisture, 0-3" depth:	24.8% water (gravimetric method)
% cloud cover:	0% (clear)
% relative humidity:	not recorded
Soil surface condition:	some crop residue on the surface, cultivated in well after Furadan 4F application
Crop stage:	V5 (Hanway 1997)

Rainfall and Irrigation

April	10	0.45 inch
	15	0.55 inch
	27	0.45 inch
	30	0.20 inch
Total			1.65 inches
May	08	0.75 inch
	18	0.40 inch
	20	0.20 inch
	26	0.90 inch
	30	0.25 inch
Total			2.50 inches
June	10	0.70 inch
	12	0.30 inch
	13	0.45
	15	0.20 inch
	20	0.80 inch
	24	1.80 inches
	25	2.20 inches
Total			6.45 inches
July	02	0.20 inch
	04	0.50 inch
	12	0.50 inch
	16	0.25 inch
	18	0.80 inch
	20	0.20 inch
	28	0.60 inch
	29	0.30 inch
Total			3.35 inches

Irrigation was applied once between planting and root damage evaluation - 9 June 2000, 0.60 inches

Experimental Formulations/Applications Evaluated - 2000

Compound	Company
Aztec 2.1G BD	Bayer
CRAG-00011	Stockhausen, Inc.
Force CS	Zeneca

Root Damage Evaluation


Insecticide	Rate/Placement^a oz ai/1000 ft.	Mean Root Damage Rating (1-6 scale)

Counter 20 CR	1.2 TB	2.15 a
Regent 4 SC	see footnote b	2.15 a
Force 3G	0.12 TB	2.30 ab
Force CS	0.12 I 2 gpa, mtube	2.50 a-c
Regent 4 SC	see footnote c	2.60 a-d
Aztec 2.1G	0.141 TB	2.70 a-e
Pilot 15G	1.2 TB	2.75 a-e
Force CS	0.12 TB 5 gpa	2.75 a-e
Force 3G	0.12 I	2.80 b-f
Furadan 4F	see footnote d	2.80 b-f
Aztec BD 2.1G	0.141 TB	2.85 b-f
Capture 2EC	0.0875 TB 5 gpa	2.90 b-f
Capture 2EC	0.0875 I 2 gpa, mtube	2.95 c-f
Capture 2EC	0.075 TB 5 gpa	3.05 c-f
CRAG-00011 20G	0.9 TB	3.05 c-f
Lorsban 15G	1.2 I	3.05 c-f
Lorsban 15G	1.2 TB	3.15 d-f
Capture 2EC	0.075 I 2 gpa, mtube	3.15 d-f
Aztec BD 2.1G	0.110 TB	3.30 e-g
CRAG-00011 20G	1.2 TB	3.40 fg
Capture 2EC	see footnote e	3.90 gh
CRAG 00011 20G	0.6 TB	4.35 hi
Thimet 20G	1.2 TB	4.40 hi
Untreated		4.80 ij
Untreated		5.15 j

Means followed by the same lower case letter are not significantly different from each other (ANOVA, LSD test, P > 0.05).

^a placement:
I = Placement directly into open seed furrow
TB = T-band, 7-inch band placed over the open seed furrow
mtube = microtube, gpa = gallons per acre

^bRegent:
rate: 0.13 lb ai/A; volume: 4 gallons 10-34-0 fertilizer/A through microtube into open seed furrow

^cRegent:
rate: 0.13 lb ai/A; volume: 1 gallon water/A through microtube into open seed furrow

^dFuradan:
rate: 1.0 lb ai/A; broadcast application on 2 June 2000, 28.8 gpa, 20 psi, Teejet 8004 nozzle tips

^eCapture:
rate: 0.05 oz ai/1000' I, 2 gpa mtube; 0.025 oz ai/1000' banded over closed seed furrow

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