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Schedule for data collection and trial maintenance in 2018–2020_
| Task | 2018 | 2019 | 2020 |
|---|---|---|---|
| Preplant soil sample | May 16 (37 DBP)a | May 4 (40 DBP) | May 18 (24 DBP) |
| Fumigation | May 22 (31 DBP) | May 13 (31 DBP) | May 22 (20 DBP) |
| Nematicide broadcast spray applicationsb | June 11 (11 DBP) | June 4 (9 DBP) | June 3 (8 DBP) |
| Sweet potato planted | June 22 | June 13 | June 11 |
| Midseason soil sample | August 23 (64 DAP) | August 16 (64 DAP) | August 3 (53 DAP) |
| Harvest soil sample | October 4 (106 DAP) | October 31 (139 DAP) | November 6 (149 DAP) |
| Sweet potato harvest | October 23 (127 DAP) | November 1 (140 DAP) | November 11 (154 DAP) |
Sweet potato tuber yield (Mg/ha) by grade category and tuber gall rating as affected by nematicide treatments in 2019 and 2020_a
| Treatment | USDA 1 (Mg/ha)b | USDA 2 (Mg/ha) | Defects (Mg/ha) | Size outliers (Mg/ha) | Percent defectsc | Tuber galling (%)d |
|---|---|---|---|---|---|---|
| 2019 | ||||||
| Control | 1.03 b | 2.31 | 16.2 | 0.47 b | 84 | 0.41 |
| Fluazaindolizine | 2.76 ab | 2.60 | 16.29 | 0.87 ab | 74 | 1.06 |
| 1.12 kg/ha | ||||||
| Fluazaindolizine | 2.40 b | 4.84 | 17.56 | 0.94 ab | 68 | 0.03 |
| 2.24 kg/ha | ||||||
| Fluazaindolizine | 4.46 a | 4.70 | 16.82 | 2.49 a | 60 | 0.21 |
| 1.12 kg/ha + oxamyl | ||||||
| 1,3-D | 1.59 b | 4.17 | 20.99 | 0.85 ab | 76 | 0.67 |
| Fluopyram | 0.85 b | 4.30 | 16.06 | 1.03 ab | 73 | 1.14 |
| Oxamyl | 2.51 b | 4.97 | 14.92 | 0.27 b | 67 | 0.57 |
| 2020 | ||||||
| Control | 1.73 b | 1.93 b | 11.02 | 0.27 | 73 a | 7.14 ab |
| Fluazaindolizine | 1.57 b | 2.80 b | 13.71 | 0.25 | 75 a | 8.51 a |
| 1.12 kg/ha | ||||||
| Fluazaindolizine | 1.84 b | 2.24 b | 12.84 | 0.34 | 76 a | 6.18 ab |
| 2.24 kg/ha | ||||||
| Fluazaindolizine | 1.99 b | 2.62 b | 11.45 | 0.29 | 69 ab | 8.22 a |
| 1.12 kg/ha + oxamyl | ||||||
| 1,3-D | 7.64 a | 8.33 a | 20.16 | 0.20 | 55 b | 0.60 c |
| Fluopyram | 1.84 b | 2.04 b | 17.03 | 0.27 | 81 a | 3.93 bc |
| Oxamyl | 1.99 b | 1.86 b | 13.35 | 0.27 | 78 a | 6.50 ab |
Nematicide application treatment rates and application methods in 2018–2020 trials_
| Treatment | Product | Active ingredient | Product application rate | Application rate (a.i.) | Application method |
|---|---|---|---|---|---|
| 1 | Untreated control | ||||
| 2 | Salibroa | Fluazaindolizine | 2.24 L/ha | 1.12 kg/ha | Broadcast spray |
| 3 | Salibro | Fluazaindolizine | 4.48 L/ha | 2.24 kg/ha | Broadcast spray |
| 4 | Salibro + Vydate Lb | Fluazaindolizine + oxamyl | 2.24 L/ha + 9.35 L/ ha | 1.12 kg/ha + 2.14 kg/ha | Broadcast spray |
| 5 | Telone IIb | 1,3-D | 74 L/ha | 84 kg/ha | Broadcast shank fumigation |
| 6 | Velum Primec | Fluopyram | 499 mL/ha | 238 g/ha | Broadcast spray (2018–2019) Drench (2020) |
| 7 | Vydate L | Oxamyl | 9.35 L/ha | 2.14 kg/ha | Broadcast spray |