Table 1.
Locations, crop information, SCN sampling dates, and initial SCN counts for each field site in this study.
| Year | Location | Experiment | Planting Date | Harvest Date | Previous Crop | Irrigationz | Sampling Date for SCN | Date of SCN Female Count | Initial SCN County | |
|---|---|---|---|---|---|---|---|---|---|---|
| At Planting | End of Season | |||||||||
| 2020 | Georgetown, DE | 1 | 19 Apr | 22 Oct | Soybean | Yes | 19 Apr | 14 Sept | 16 Jun | 936 |
| 2021 | Georgetown, DE | 1 | 27 Apr | 5 Nov | Soybean | Yes | 27 Apr | 27 Aug | 3 Jun | 61 |
| 2021 | Queenstown, MD | 1 | 4 Jun | 12 Nov | Corn | No | 18 May | 1 Sept | 7 Jul | 31 |
| 2020 | Georgetown, DE | 2 | 19 Apr | 22 Oct | Soybean | Yes | 19 Apr | 6 Oct | 15 Jun | 34263 |
| 2021 | Georgetown, DE | 2 | 27 Apr | 5 Nov | Soybean | Yes | 27 Apr | 13 Sept | 3 Jun | 3917 |
z Water was applied through overhead irrigation during the summer months to supplement natural rainfall.
y Initial soybean cyst nematode (SCN) counts in spring prior to or at the time of planting. Experiment 1 is the average number of SCN J2 and cysts/500 cm3 soil across all plots for each year and Experiment 2 is the average number of SCN eggs/250 cm3 soil across all plots for each year.
Table 2.
Seed treatments used in field trials from 2020–2021.
| Treatment Name | Product Name | Active Ingredient (AI) | Application Rate | Mode of Action | Group |
|---|---|---|---|---|---|
| Nontreated1,2 | n/a | n/a | n/a | n/a | n/a |
| Fungicide + Insecticide base2 | Allegiance FL Stamina Systiva XS Xemium Poncho 600 | Metalaxyl Pyraclostrobin Fluxapyroxad Clothianidin | 4 g a/100 kg 7.5 g a/100 kg 5 g a/100 kg 0.11 mg a/seed | PA QoI SDHI nAChR | Group 4 Group 11 Group 7 Group 4(A) |
| Saltro1 + base2 | Saltro® | Pydiflumetofan | 0.075 mg a/seed | SDHI | – |
| ILEVO1 + base2 | ILEVO® | Fluopyram | 0.15 mg a/seed | SDHI | N-3 |
| Clariva + base2 | Clariva®pn | P. nishizawae | 130 ml/100 kg | Biologic | N-UNB |
| Trunemco + base2 | Trunemco™ | B. amyloliquefaciens cis–jasmone | 20.2 ml/100 kg | Biologic | N-UNB |
| Aveo EZ + base2 | Aveo™ EZ | B. amyloliquefaciens strain PTA-4838 | 2 ml/100,000 seeds | Biologic | N-UNB |
| BioST + base2 | BioST®Nematicide100 | Burkholderia rinojenses | 195 ml/100 kg | Biologic | N-UNB |
1 Indicates use in Experiment 1
2 Indicates use in Experiment 2
Table 3.
Experiment 1 - Emergence, nematode Reproductive Factor (Rf) values, female counts, and yield data.
| Trial Information | % Emergence 14 DAPz | % Emergence 28 DAP | Rfy | Transformed Rfx | Root female counts | Females per gram of root | Yield(kg/ha) | Yield difference from nontreated seed (kg/ha) |
|---|---|---|---|---|---|---|---|---|
| 2020, Georgetown | ||||||||
| Nontreated | 26.2c | 54.0b | 0.6 | −0.33 | 189.0a | 19.1a | 2125.1 | – |
| Saltro | 54.3b | 90.5a | 0.2 | −0.67 | 179.2a | 23.9a | 2313.4 | +188.3 |
| ILEVO | 70.0a | 86.4a | 0.2 | −0.83 | 53.8b | 5.4b | 2447.9 | +322.8 |
| p-value | 0.0001 | 0.0001 | ns | ns | 0.03 | 0.01 | ns | |
| 2021, Georgetown | ||||||||
| Nontreated | 53.3c | 56.8c | 7.6 | 0.19 | 531.6 | 125.8 | 2838 | – |
| Saltro | 82.4a | 85.5a | 3.6 | 0.75 | 473.4 | 94.8 | 3275.1 | +437.1 |
| ILEVO | 68.9b | 79.5b | 6.6 | 0.69 | 482.2 | 115.3 | 3281.9 | +443.9 |
| p-value | <0.001 | 0.0001 | ns | ns | ns | ns | ns | |
| 2021, Queenstown | ||||||||
| Nontreated | 53.3c | 56.8b | 76.17 | 0.74 | 1.6 | 0.1 | 4848.8 | – |
| Saltro | 82.5 | 85.5a | 46.2 | 1.91 | 2.6 | 0.1 | 4815.2 | −33.6 |
| ILEVO | 68.9a | 79.5a | 8.51 | −0.06 | 0.8 | 0.05 | 4909.3 | +60.5 |
| p-value | <0.001 | <0.0001 | ns | ns | ns | ns | ns | |
z Means followed by the same letter are not significantly different based on Fisher's Least Significant Difference (LSD; α = 0.05). ns = not significant.
y The reproductive factor (Rf) was calculated by dividing the final population density [Pf] by the initial population density [Pi] to generate a ratio to measure the change in number of SCN J2's per 500 cm3 of soil over the entire growing season for each plot. When Rf=1, no change in SCN population density occurred in the season; if Rf <1, there was a decrease in SCN population density over the season; if Rf >1, there was an increase in SCN population density.
Table 4.
Experiment 2 – Emergence, nematode Reproductive Factor (Rf) values, female counts, and yield.
| Trial Information | % Emergence 14 DAPz | % Emergence 28 DAP | Rfy | Transformed Rfx | Root female counts | Females per gram of root | Yieldkg/ha | Yield difference from base seed treatment (kg/ha) |
|---|---|---|---|---|---|---|---|---|
| Georgetown, 2020 | ||||||||
| Nontreated | 74.6 | na | 0.5 | −0.40 | 239 | 40.5 | 2353.8 | +316.1 |
| Fungicide + Insecticide Base | 73.1 | na | 0.6 | −0.29 | 380 | 57.7 | 2037.7 | − |
| BioST | 70.6 | na | 0.5 | −0.39 | 323 | 46.8 | 2454.6 | +416.9 |
| Aveo + Base | 75.4 | na | 0.7 | −0.37 | 270.8 | 39.2 | 2528.6 | +490.9 |
| Clariva + Base | 76.2 | na | 0.4 | −0.40 | 290.7 | 37.8 | 2750.5 | +712.8 |
| ILEVO + Base | 77.0 | na | 0.7 | −0.25 | 200.8 | 34.6 | 2219.3 | +181.6 |
| Trunemco + Base | 76.0 | na | 0.6 | −0.29 | 292.0 | 43.9 | 2313.4 | +257.7 |
| Saltro + Base | 77.7 | na | 0.6 | −0.30 | 333.0 | 50.0 | 2084.8 | +47.1 |
| p-value | ns | na | ns | ns | ns | ns | ns | |
| Georgetown, 2021 | ||||||||
| Nontreated | 47.3c | 48.51c | 6.8 | 0.77 | 341.5 | 55.6 | 2885.1 d | −416.9 |
| Fungicide + Insecticide Base | 69.9ab | 76.07ab | 6.4 | 0.78 | 450.8 | 71.5 | 3302 b | − |
| BioST | 69.2ab | 74.4ab | 8.4 | 0.84 | 392.7 | 52.1 | 3328.9 b | +26.9 |
| Aveo + Base | 70.3ab | 78.8a | 6.4 | 0.78 | 394.9 | 55.4 | 3059.9 c | −242.1 |
| Clariva + Base | 76.1a | 78.7a | 6.9 | 0.79 | 428.8 | 62.9 | 3080.1 c | −221.9 |
| ILEVO + Base | 68.0ab | 74.0ab | 8.0 | 0.82 | 202.8 | 36.5 | 3402.9 b | +100.9 |
| Trunemco + Base | 73.5ab | 76.6ab | 8.7 | 0.90 | 276.2 | 44.0 | 3295.3 b | −6.7 |
| Saltro + Base | 66.9b | 72.5b | 6.9 | 0.80 | 305.5 | 46.3 | 3813.1 a | +511.1 |
| p-value | <0.0001 | <0.0001 | ns | ns | ns | ns | 0.0005 | |
z Means followed by the same letter are not significantly different based on Fisher's Least Significant Difference (LSD; α = 0.05). ns = not significant.
y The reproductive factor (Rf) was calculated by dividing the final population density [Pf] by the initial population density [Pi] to generate a ratio to measure the change in number of SCN eggs per 250 cm3 of soil over the entire growing season for each plot. When Rf=1, no change in SCN population density occurred in the season; if Rf <1, there was a decrease in SCN population density over the season; if Rf >1, there was an increase in SCN population density.