Corn Rootworm
Final Report 1999
Keith Jarvi
Integrated Pest Management
Background information pertaining to corn rootworm larva insecticide
experiments conducted at the University of Nebraska Northeast Research and Extension
Center near Concord, NE, 1999.
Species
- Diabrotica virgifera virgifera LeConte (western corn rootworm)
Diabrotica barberi Smith and Lawrence (northern corn rootworm)
Agronomic
| Hybrid: |
Pioneer 3394 |
| Row Spacing: |
30 inches |
| Planting Date: |
10 May |
| Furadan Application: |
21 June |
| Planter: |
John Deere Maxemerge 2 row |
| Planting Depth: |
2 inches |
| Application Equipment: |
Granules at planting: Planter mounted
cone-belt system |
| v |
Regent liquid formulations: Microtube at 1 or
5 gal solution/acre |
| Field Preparation: |
Disked 7 Nov 1998 20 April 1999 Field
cultivate 10 May
1999 |
| Herbicides: |
Extrazine DF 3 lb/acre 18 May |
| Cultivation: |
23 June |
| Fertilizer: |
Anhydrous 100 lbs actual N 13 April |
| Previous Crop: |
Corn (trap) |
| Soil Type: |
Kennebec silt loam |
| Organic Matter: |
3 % |
| ph |
6.5 |
| Field History: |
Late planted mixed variety field corn trap
1998 |
| Irrigation: |
None |
| Plot Direction: |
North-South |
Experimental Design and Evaluation
- Randomized complete block with 4 replications
- Ratings: Iowa 1-6 scale
- Dug and rated 14 - 15 July
- Plant populations taken 25 June, plants per 30 ft of row
Comments: Warm, mild winter favored egg survival. Untreated check plot had light
damage. Early growing season wet with excess moisture. Plots in standing water June 27-28
may have reduced rootworm populations significantly. Growing degree days near average. See
attached sheet for rainfall events.
Corn Rootworm Insecticide Screening Experiment
Haskell Ag Lab, Concord NE 1999.
Keith Jarvi
Application Methods:
- TB = 7 inch T-band in front of press wheel at planting time
- IF = In-furrow in front of press wheel at planting time
- B = 15" Band over the row on 18 June
- MT = Microtube at planting
- ST = Seed Treatment
Insecticide Screening Concord, NE 1999 Root Ratings
Treatment |
Application Method |
Rate
Form./Acre |
Rate
lb AI/Acre |
Root Rating |
| Counter 20 CR |
TB |
6 oz |
1.20 |
1.80 a |
| Counter 20 CR |
IF |
6 oz |
1.20 |
2.00 ab |
| Force 3 G |
TB |
4 oz |
0.12 |
2.10 abc |
| Regent 4 SC |
MT |
5 gal |
0.13 |
2.10 abc |
| Aztec 2.1 G |
IF |
6.7 oz |
0.14 |
2.20 abc |
| Aztec 2.1 G BD |
TB |
6.7 oz |
0.14 |
2.25 abc |
| Force 3 G |
IF |
4 oz |
0.12 |
2.25 abcd |
| Furadan 4 F |
B |
1 qt broadcast rate simulation |
1.00 |
2.35 abcd |
| Lorsban 15 G |
TB |
8 oz |
1.20 |
2.35 abcd |
| Aztec 2.1 G |
TB |
6.7 oz |
0.14 |
2.40 abcd |
| American Ag Services #1 |
Pre-treated seed |
x |
x |
2.40 abcd |
| Untreated |
x |
x |
x |
2.50 bcd |
| American Ag Services #2 |
Pre-treated seed |
xx |
xx |
2.50 bcd |
| American Ag Services #3 |
Pre-treated seed |
xxx |
xxx |
2.55 bcd |
| Lorsban 15 G |
IF |
8 oz |
1.20 |
2.60 bcd |
| Regent 4 SC |
MT |
1 gal |
0.14 |
2.70 cd |
| American Ag Services #4 |
Pre-treated seed |
x |
x |
2.85 d |
Means with the same letter are not significantly different. (LSD =
0.6225; alpha = 0.05)
Insecticide Screening Concord, NE 1999
Plant Population
Treatment |
Application
Method |
Rate
Form./Acre |
Rate
lb AI/Acre |
Plant
Population |
| Regent 4 SC |
MT |
1 gal |
0.13 |
35.25 a |
| Force 3 G |
TB |
4 oz |
0.12 |
34.75 ab |
| Aztec 2.1 G |
IF |
6.7 oz |
0.14 |
34.25 abc |
| Counter 20 CR |
TB |
6 oz |
1.20 |
34.00 abc |
| American Ag
Services #3 |
Pre-treated seed |
x |
x |
34.00 abc |
| Force 3 G |
IF |
4 oz |
0.12 |
33.75 abc |
| Lorsban 15 G |
IF |
8 oz |
1.20 |
33.50 abc |
| Regent 4 SC |
MT |
5 gal |
0.13 |
33.00 abcd |
| Aztec 2.1 G BD |
TB |
6.7 oz |
0.14 |
33.00 abcd |
| Counter 20 CR |
IF |
6 oz |
1.20 |
32.75 abcd |
| Aztec 2.1 G |
TB |
6.7 oz |
0.14 |
32.75 abcd |
| Untreated |
x |
x |
x |
32.25 abcd |
| Furadan 4 F |
B |
1 qt broadcast
rate simulation |
1.00 |
31.50 abcd |
| American Ag
Services #1 |
Pre-treated seed |
x |
x |
31.50 abcd |
| Lorsban 15 G |
TB |
8 oz |
1.2 |
31.00 bcd |
| American Ag
Services #4 |
Pre-treated seed |
x |
x |
30.50 cd |
| American Ag
Services #2 |
Pre-treated seed |
x |
x |
29.50 d |
Means with the same letter are not significantly different. (LSD =
3.9478; alpha = 0.05)
Rainfall
May 10 - July 14, 1999, Concord, NE (Events at least .05 inch)
Total Rainfall 10.36 inches
May 10 |
v |
0.59 |
|
June 1 |
v |
1.92 |
|
July 2 |
v |
0.69 |
17 |
v |
0.07 |
|
3 |
v |
0.06 |
|
8 |
v |
0.14 |
20 |
v |
0.17 |
|
4 |
v |
0.24 |
|
Total |
v |
0.83 |
22 |
v |
0.91 |
|
5 |
v |
0.15 |
|
v |
v |
v |
30 |
v |
0.45 |
|
9 |
v |
0.06 |
|
|
|
|
31 |
v |
0.36 |
|
10 |
v |
1.04 |
|
|
|
|
Total |
v |
2.55 |
|
15 |
v |
1.21 |
|
|
|
|
| v |
v |
v |
|
27 |
v |
2.25 |
|
|
|
|
|
|
|
|
30 |
v |
0.05 |
|
|
|
|
|
|
|
|
Total |
v |
6.98 |
|
|
|
|
|
|
|
|
v |
v |
v |
|
|
|
|
|