Corn Rootworm Larva Insecticide Evaluations 2000 |
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Conducted by:
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Keith
Jarvi University of Nebraska Northeast Research and Extension Center 601 E Benjamin Avenue Suite 104 Norfolk NE 68701-0812 (402) 370-4016 |
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| Background information | ||
| Background information pertaining to corn rootworm larva insecticide experiments conducted at the University of Nebraska Haskell Ag Lab near Concord, NE, 2000. | ||
| Species | ||
| Diabrotica
virgifera virgifera LeConte (western corn rootworm) Diabrotica barberi Smith and Lawrence (northern corn rootworm) |
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| Agronomic | ||
Hybrid: |
Novartis 58D1 |
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Row Spacing: |
30 inches |
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Planting Date: |
May |
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Furadan Application: |
6 June |
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Planter: |
John Deere Maxemerge, 2 row |
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Planting Depth: |
2 inches |
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Application Equipment: |
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| Granules
at planting: Planter mounted cone-belt system Regent liquid formulations: Microtube
in-furrow at 1 or 5 gal solution/acre |
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| Field Preperation | Fall disk 20 Oct 1999 | |
| Fertilization: | Urea 48-0-0 applied 3/30 disked in 4/4 173 lb (80 lb actual) | |
| Herbicides: | Harness Extra at 2.3 qts/acre 5/1 disked in 5/2 AM | |
| Cultivation: | 19 June | |
| Previous Crop: | Corn (trap) | |
| Soil Type: | Kennebec silt loam | |
| Organic Matter: | 3 % | |
| ph | 6.5 | |
| Field History: | Late planted mixed variety field corn trap 1999 | |
| Irrigation: | None | |
| Plot Direction: | North-South | |
| Experimental Design and Evaluation | ||
| Randomized
complete block with 4 replications Ratings: Iowa 1-6 scale |
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| Comments: Warm, mild winter favored egg survival. Untreated check plot had heavy damage. Started the year with very short subsoil moisture, May and June slightly above average rainfall, then very dry again. Plots flooded for several hours on June 25. Growing degree days near average. See attached sheet for rainfall events. | ||
Corn Rootworm
Insecticide Screening Experiment |
| 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 6 June MT = Microtube at planting |
Insecticide
Screening Concord, Nebraska |
| Treatment | Application Method |
Rate |
Rate |
Root Rating |
| Counter 20 CR | TB | 6 oz | 1.20 | 2.50 a |
| Fortress 5 G | TB | 3 oz | 0.15 | 2.55 ab |
| Fortress 5 G | IF | 3 oz | 0.15 | 2.60 ab |
| Aztec 2.1 G | TB | 6.7 oz | 0.14 | 2.70 ab |
| Aztec 2.1 G BD | TB | 6.7 oz | 0.14 | 2.80 abc |
| Lorsban 15 G | TB | 8 oz | 1.20 | 2.90 abcd |
| Counter 20 CR | IF | 6 oz | 1.20 | 3.00 bcde |
| Regent 4 SC | IF MT 5 gal |
0.24 oz | 0.13 | 3.20 cdef |
| Lorsban 15 G | IF | 8 oz | 1.20 | 3.20 cdef |
| Force 3 G | TB | 4 oz | 0.12 | 3.25 cdef |
| Force 2.5 CS | TB | 0.384 oz | 0.01 | 3.35 defg |
| Regent 4 SC | IF MT 1 gal |
0.24 oz | 0.13 | 3.40 efg |
| Capture 2 EC | TB | 0.30 oz | .0046 | 3.55 fg |
| Capture 2 EC | TB | 0.35 oz | .0054 | 3.60 fg |
| Force 3 G | IF | 4 oz | 0.12 | 3.75 gh |
| Capture 2 EC | IF | 0.30 oz | .0046 | 4.20 hi |
| Capture 2 EC | IF | 0.35 oz | .0054 | 4.45 ij |
| Capture 2 EC Split | IF MT TB |
0.20 oz 0.10 oz |
.0046 | 4.70 j |
| Untreated | - | - | - | 5.85 k |
| Furadan 4 F | B | 1 qt formulation/acre broadcast rate | - | 5.90 k |
Means with the same letter are not significantly different. (LSD = 0.4718; alpha = 0.05)
Insecticide
Screening Concord, NE 2000 |
Treatment |
Application Method |
Rate |
Rate |
Plant Population |
| Aztec 2.1 G BD | TB | 6.7 oz | 0.14 | 34.00 a |
| Force 3 G | IF | 4 oz | 0.12 | 33.75 ab |
| Force 2.5 CS | TB | 0.384 oz | 0.01 | 32.75 abc |
| Regent 4 SC | IF MT 1 gal |
0.24 oz | 0.13 | 32.50 abc |
| Capture 2 EC Split | IF MT TB |
0.20 oz 0.10 oz |
.0046 | 32.00 abc |
| Counter 20 CR | TB | 6 oz | 1.20 | 31.75 abcd |
| Lorsban 15 G | IF | 8 oz | 1.20 | 31.50 abcd |
| Force 3 G | TB | 4 oz | 0.12 | 31.25 abcd |
| Aztec 2.1 G | TB | 6.7 oz | 0.14 | 31.00 abcd |
| Capture 2 EC | TB | 0.30 oz | .0046 | 30.75 abcd |
| Counter 20 CR | IF | 6 oz | 1.20 | 30.50 abcd |
| Fortress 5 G | IF | 3 oz | 0.15 | 30.25 abcd |
| Capture 2 EC | IF | 0.30 oz | .0046 | 30.00 abcd |
| Regent 4 SC | IF MT 5 gal |
0.24 oz | 0.13 | 29.50 abcd |
| Capture 2 EC | IF | 0.35 oz | .0054 | 29.50 abcd |
| Fortress 5 G | TB | 3 oz | 0.15 | 29.00 bcd |
| Untreated | - | - | - | 29.00 bcd |
| Lorsban 15 G | TB | 8 oz | 1.20 | 28.50 cd |
| Capture 2 EC | TB | 0.35 oz | .0054 | 28.25 cd |
| Furadan 4 F | B | 1 qt formulation/acre broadcast rate | - | 27.00 d |
| Means with the same letter are not significantly different. (LSD = 4.8561; alpha = 0.05) | ||||
Rainfall at the Haskell Ag Lab, Concord, NE January 1 – July 14, 2000 |
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| Month | Date | Amount | Month | Date | Amount |
| January | 18 | .133 | February | 7 | .215 |
| 23 | .429 | 23 | .429 | ||
| Total | .644 | Total | .644 | ||
| March | 8 | .290 | April | 4 | .02 |
| 14 | .101 | 7 | .03 | ||
| 17 | .184 | 15 | .07 | ||
| 18 | .155 | 16 | .64 | ||
| 19 | .02 | 20 | .01 | ||
| 19 | .123 | 25 | .07 | ||
| 23 | .292 | 26 | .39 | ||
| Total | 1.145 | 27 | .07 | ||
| - | 30 | .01 | |||
| May | 7 | .44 | Total | 1.31 | |
| 8 | .04 | ||||
| 10 | .01 | July | 1 | .03 | |
| 17 | .68 | 2 | .01 | ||
| 25 | .59 | 4 | .03 | ||
| 26 | .67 | 5 | .16 | ||
| 29 | .94 | 10 | .04 | ||
| 30 | .12 | 11 | .32 | ||
| Total | 5.49 | 14 | .02 | ||
| - | Total | .61 | |||
| June | 1 | .14 | |||
| 3 | .18 | ||||
| 12 | .42 | ||||
| 13 | .15 | ||||
| 14 | .01 | ||||
| 15 | .05 | ||||
| 19 | .29 | ||||
| 20 | .11 | ||||
| 23 | 1.55 | ||||
| 24 | .08 | ||||
| 25 | 2.37 | ||||
| 27 | .76 | ||||
| 28 | .08 | ||||
| 29 | .01 | ||||
| Total | 6.20 | ||||