Haskell Ag Lab, Concord NE 1998
Background information pertaining to corn rootworm larva insecticide experiments conducted at the University of Nebraska Northeast Research and Extension Center near Concord, NE, 1998.
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 | 5 May |
| Furadan Application | 18 June |
| Planter | John Deere Maxemerge , 2 row |
| Planting Depth | 2 inches |
| Application Equipment | Granules at planting: Planter mounted cone-belt system |
| Regent liquid formulations: | Microtube at 1 or 2 gal solution/acre |
| Field Preparation | Disked twice 4 May |
| Herbicides | Extrazine DF 3 lb/acre 20 May |
| Cultivation | 22 June |
| Fertilizer | Anhydrous 100 lbs actual N 30 April |
| Previous Crop | Corn (trap) |
| Soil Type | Kennebec silt loam |
| Organic Matter | 3 % |
| Field History | Late planted mixed variety field corn trap 1997 |
| Irrigation | None |
| Plot Direction | North-South |
Experimental Design and Evaluation
Randomized complete block with 4 replications
Ratings: Iowa 1-6 scale
Dug and rated 16 July
Comments: Warm, mild winter favored egg survival. Untreated check plot had moderate damage. Growing season good with excellent moisture. Growing degree days near average. See attached sheet for rainfall events.
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
Insecticide Screening Concord, NE 1998
Treatment |
Application Method |
Rate |
Rate |
Root Rating |
| Force 3 G | TB | 4 oz | 0.12 | 1.90 a |
| Furadan 4 F | B | 1 qt broadcast rate simulation | 1.0 | 2.05 ab |
| Aztec 2.1 G | TB | 6.7 oz | 0.14 | 2.10 abc |
| Force 3 G | IF | 4 oz | 0.12 | 2.10 abc |
| Aztec 4.67 G | IF | 3 oz | 0.14 | 2.20 abc |
| Lorsban 15 G | TB | 8 oz | 1.20 | 2.25 abcd |
| Aztec 2.1 G | IF | 6.7 oz | 0.14 | 2.30 abcd |
| Aztec 4.67 G | TB | 3 oz | 0.14 | 2.35 abcd |
| Regent 4 SC | MT | 4 qt | 0.13 | 2.40 bcd |
| Regent 80 WG | MT | 4 qt | 0.13 | 2.45 bcde |
| Regent 80 WG | MT | 8 qt | 0.13 | 2.55 cde |
| Counter 20 CR | IF | 6 oz | 1.20 | 2.70 def |
| Counter 20 CR | TB | 6 oz | 1.20 | 2.90 ef |
| Lorsban 15 G | IF | 8 oz | 1.20 | 3.10 f |
| Untreated | - | - | - | 3.60 g |
Means with the same letter are not significantly different. (LSD = 0.4667; alpha = 0.05)
May |
June |
July |
|||
| 5 | 0.14 | 3 | 0.15 | 3 | 0.28 |
| 11 | 0.08 | 4 | 0.05 | 5 | 0.07 |
| 12 | 0.53 | 5 | 0.32 | 6 | 0.14 |
| 16 | 1.12 | 7 | 0.17 | 7 | 0.94 |
| 20 | 0.45 | 8 | 0.62 | 9 | 0.56 |
| 22 | 0.50 | 9 | 0.85 | 22 | 0.08 |
| 24 | 0.05 | 12 | 0.51 | 30 | 0.42 |
| Total | 2.87 | 15 | 0.94 | Total | 2.49 |
| 17 | 0.14 | ||||
| 18 | 0.71 | ||||
| 24 | 0.47 | ||||
| 30 | 1.16 | ||||
| Total | 6.42 | ||||