Dennis Mills, Extension Associate, Plant Pathology
Tony Nye, Agriculture and Natural Resources Extension Agent, Clinton County
James Wiedenheft, Agriculture and Natural Resources Extension Agent, Ottawa County
Chris Bruynis, Agriculture and Natural Resources Extension Agent, Wyandot County
Anne E. Dorrance, Assistant Professor, Plant Pathology
To evaluate the efficacy and economics of utilizing seed treatments for management of early season Phytophthora seed rot and damping off.
| Cooperator | Ralph Hertlein |
Joe Bailey |
Craig Blausey |
Bob Millinger |
Gary Walter |
| Town | Martinsville | Blanchester | Martin | Graytown | Upper Sandusky |
| County | Clinton | Clinton | Ottawa | Ottawa | Wyandot |
| Soil Type | Avonburg silt loam |
Avonburg silt loam |
Nappanee silty clay loam |
Toledo silty clay |
Pewamo silty clay loam |
| Plot Size | 40' x 765' | 40' x 900' | 45' x 1547' | 25' x 750' | 40' x 800' |
| Planting Date | 5 May | 19 Jun | 20 Jun | 10 May | 14 May |
| Harvest Date | 1 Oct | 30 Oct | 8 Nov | 1 Nov | 2 Oct |
| Moisture (avg.) | 10.0% | 12.4% | 10.8% | 12.8% | 11.6% |
This study was conducted on farmers' fields at five locations in Ohio. One fungicide seed treatment was evaluated — Rival XL (4 fl oz/cwt) plus Allegiance (1.5 fl oz/cwt) and an untreated control at each location. The soybean variety, Resnik, with moderate (5) partial resistance, was used. The study design was side-by-side comparisons used across the fields with a minimum of four to 14 replications per farm. Seed was treated by Ohio Foundation Seeds prior to purchase. Plot size varied per farm based on field size, equipment widths, and seed available (10A). Early and mid-season population stand counts were taken from eight to 14 subplots that measured 3 feet x 3 feet.
| Table 1. Soybean Stand Count and Yield. | ||||
| Location | Treatment | Stand | Yield | |
| Early Season Plants per 9 ft2 |
Mid-Season Plants per 9 ft2 |
bu/A | ||
| Hertlein | untreated | 30.4 | 26.4 | 50.5 |
| treated | 24.0 | 24.4 | 51.9 | |
| LSD (0.05) | NS | NS | NS | |
| Bailey | untreated | 30.6 | 29.8 | 37.7 |
| treated | 33.0 | 32.8 | 39.7 | |
| LSD (0.05) | NS | NS | NS | |
| Millinger | untreated | 31.7 | 32.7 | * |
| treated | 34.4 | 38.2 | * | |
| LSD (0.05) | NS | 3.8 | ||
| Blausey | untreated | 50.7 | 49.8 | * |
| treated | 47.3 | 47.0 | * | |
| LSD (0.05) | NS | NS | ||
| Walter | untreated | 26.3 | 26.0 | 38.1 |
| treated | 28.5 | 29.2 | 39.3 | |
| LSD (0.05) | NS | NS | NS | |
| * Missing data | ||||
Seed treatments did not negatively impact yield nor did they significantly benefit yield at these five locations. In the Millinger, Ottawa County, trial, mid-season stand counts were significantly different. Weather conditions following planting did not favor development of Phytophthora or Pythium. Planting was delayed due to wet conditions early at the Blausey and Bailey locations, but soils dried out following planting and were unfavorable for disease development. A seed treatment will only be effective if environmental conditions for disease develop within the first three weeks after planting.
For additional information, contact:
Dennis Mills
OARDC Plant Pathology
1680 Madison Avenue
Wooster, OH 44691
330-202-3566
mills.255@osu.edu