2005 CORN ROOTWORM SOIL INSECTICIDE
EFFICACY EXPERIMENT1
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
Background information pertaining to the experiment conducted at the ARDC, near Mead, Nebraska during 2005.
| Background Information - Agronomic | Background Information - Entomology |
| Experimental Design | Environmental Conditions at Planting |
| Rainfall and Irrigation | Root Damage Evaluations |
| Hybrids: | DKC 60-15, DKC-12 |
| Row Spacing: | 30 inches |
| Planting Date: | 3 May 2005 |
| 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: | 17 March 2005 - chopped and disked, 18 April 2005 - disked |
| Herbicides Applied: | 4 May 2005: Harness Xtra, 2.0 qt/A, pre emerge |
| 7 June 2005: 1.0 oz/A SPIRIT | |
| Fertilizer Applied: | 150 lb. N/A applied as NH3, 1 April 2005 |
| 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/33.5' ± SEM = 37.9 ± 0.5. |
| Insecticide History: | Insecticide free: 1998, 2000, 2002 Multiclass soil insecticide trials: 1997, 1999, 2001, 2003 |
| Species present: | Northern corn rootworm, Diabrotica barberi Smith and Lawrence, and western corn rootworm, D. virgifera virgifera LeConte. Initial rootworm egg hatch occurred between 30-31 May 2005 (predominantly western corn rootworm). |
| Root Evaluation: | 1 - 6 (Hills and Peters, 1971) and 0 - 3 root rating scales (Oleson et al. 2005) were used to evaluate larval corn rootworm damage in each treatment. Five roots per replication were evaluated in each treatment. |
| Root Evaluation Date: | 14 July 2005 |
Design: Randomized complete block design
Replicated four times
Single-row treatments
Row Length: 33.5 feet
Statistical Analysis: Root Ratings, Lodging, Stand Counts: Used SAS Mixed Procedure; Protected LSD test was used for mean separation (P # 0.05) .
Environmental Conditions at planting:
Air temperature: 13.5EC
Wind speed: 5-10 mph at 5 ft height
Wind direction: N - NW
Soil temperature 2" depth: 17EC
Soil temperature surface: 22EC
Soil moisture, 0-3" depth: 10.41% water (gravimetric method)
% cloud cover: clear, 0 % cloud cover
% relative humidity: not recorded
Residue on surface: 20% of soil surface covered with crop residue; soil moist, some clods on surface
April 06 0.08 inch
10 0.21
11 0.98
12 0.57
16 0.01
18 0.25
20 0.84
21 0.10
22 0.13
Total 3.17
May 10 0.22 inch
11 0.86
12 1.12
18 0.05
25 0.21
26 0.01
29 0.09
31 0.65
Total 3.21
June 01 0.11 inches
03 0.61
04 0.63
05 0.04
09 0.68
10 0.23
11 0.06
21 0.01
25 0.04
27 0.14
29 0.01
Total 2.56
July 02 0.01 inches
17 0.82
18 0.02
25 2.92
26 0.18
Total 3.95
Aug 10 0.34 inches
12 0.01
13 0.01
17 0.01
26 0.28
Total 0.65
Irrigation (through July 2005):
Sprinkler irrigation was applied as needed prior to root damage evaluation
July 01 1.75 inches
07 1.5
11 0.5
12 2.0
22 1.5
Table 1. 2005 Corn Rootworm Soil Insecticide Experiment 1.
University of Nebraska Agricultural Research and Development Center, near Mead, NE
Root Damage and Lodging Evaluation
| Insecticide | Rate/Placementa | Mean Percentageb Lodged (+/- SE) | Mean Root Damage Ratingc (1 - 6 Scale) | Mean Root Damage Ratingc (0 - 3 Scale) |
|---|---|---|---|---|
| YieldGard Rootworm + Poncho 250 | 0.00 ± 0.00 | 2.20 a | 0.06 a | |
| Fortress 5G | 0.20 I smartbox appl. | 0.00 ± 0.00 | 2.60 ab | 0.18 ab |
| Aztec 4.67G | 0.14 TB smartbox appl. | 0.00 ± 0.00 | 2.65 ab | 0.14 ab |
| Counter 15G | 1.2 TB | 0.00 ± 0.00 | 2.65 ab | 0.19 ab |
| Aztec 2.1G | 0.141 TB | 0.00 ± 0.00 | 2.70 b | 0.18 ab |
| Regent 4 SC | see footnote d | 0.00 ± 0.00 | 2.70 b | 0.26 ab |
| Fortress 2.5G | 0.20 I | 3.13 ± 3.13 | 2.70 b | 0.31 abc |
| Capture 2EC | see footnote f | 0.00 ± 0.00 | 2.80 b | 0.29 abc |
| Lorsban 4E | see footnote e | 0.00 ± 0.00 | 2.85 bc | 0.30 abc |
| Lorsban 15G | 1.2 TB | 3.03 ± 2.14 | 2.90 bc | 0.30 abc |
| Force 3G | 0.12 TB | 0.00 ± 0.00 | 2.90 bc | 0.30 abc |
| Poncho 1250 | 1.25 mg ai/seed | 0.00 ± 0.00 | 2.90 bc | 0.35 abc |
| Thimet 20G | 1.2 TB | 0.00 ± 0.00 | 3.05 bc | 0.43 bc |
| Cruiser 5 FS | 1.25 mg ai/seed | 0.86 ± 0.86 | 3.30 c | 0.63 c |
| Untreated (1) | 18.04 ± 11.70 | 4.60 d | 1.82 d | |
| Untreated (2) | 19.90 ± 12.68 | 4.95 d | 2.10 d |
a Rate presented as oz ai per 1000 row ft except where other units listed:
TB = T-band, 7-inch band placed over the open seed furrow;
I = placed in the open seed furrow;
ST = seed treatment.
b On 16 August 2005, there were no significant differences (P > 0.05) in final stand count means; the
final overall mean number of plants per 33.5 ft ± SEM = 32.7 ± 0.6. The mean percentage of final
stands that were lodged are presented by treatment (lodged = plant leaning > 45E angle from vertical).
c Root rating scales used: 1 - 6 scale (Hills and Peters 1971); 0 - 3 scale (Oleson et al. 2005); 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).
d Regent 4SC rate: 0.13 lb ai/A; volume: 5 gallons water/A through microtube into open seed furrow
e Lorsban 4E rate: 1.2 oz ai/1000 ft; volume: 5 gallons water/A, TB application
f Capture 2EC rate: 0.09 oz ai/1000 ft; volume: 5 gallons water/A, TB application