Submitted to: Fungicide and Nematocide Tests
Publication Type: Research Notes
Publication Acceptance Date: 2/18/2006
Publication Date: 4/15/2006
Citation: Gundersen, B., Inglis, D., Porter, L. 2006. Evaluation of seed, in-furrow, and foliar treatments for control of root rot of peas 2005. Fungicide and Nematocide Tests (online). Report 61:V130/ DOI:10.1094/FN61. The American Phytopathological Society, St. Paul, MN. Interpretive Summary: Organic and commercial pea growers are constantly looking for ways to reduce the negative impact of seed and root rotting pathogens on plant health and production. Organic pea growers are limited in the seed treatments they can apply to seed to protect it from root rotting pathogens due to strict regulations. The purpose of the present study was to identify seed, in-furrow, and foliar treatments for commercial and organic pea production that would positively effect plant emergence, growth, and yield, while reducing disease. Of the organic seed treatments tested (GB34, Kodiak, Micro 108, Serenade ASO and T-22 Planter Box) Serenade ASO was the only biological product that significantly improved plant growth and yield compared to nontreated seed and may have potential as an organic seed treatment. In-furrow and foliar application of Phostrol present promising alternatives for commercial pea production in northwestern Washington since application of the product increased plant emergence, growth and yield.
Technical Abstract: Seven biological seed treatments (GB 34, Heads Up 1 and 2, Kodiak, Micro 108, T-22 Planter Box, and Serenade ASO), one commercial seed treatment (Allegiance + Captan), three Phostrol treatments (applied in-furrow only, applied in-furrow + at emergence, and applied at emergence + 14 days later), and one nontreated control were evaluated in a field (Puget Silt Loam soil) at WSU-NWREC near Mount Vernon, WA. The site has a long history of continuous pea production and isolates of A. euteiches, F. oxysporum f.sp. pisi, Fusarium solani f.sp. pisi, P. medicaginis, and Pythium spp. have frequently been recovered from rotted roots of diseased peas. The trial was planted to Charo at 250 lb/A on 3 May using a six-row belt planter. Treatments were replicated four times in plots arranged in a randomized complete block design. Each plot was 10 ft long with a row spacing of 7 in., seed spacing of 2 in., and seeding depth of 3 in. A pre-plant incorporated application of Treflan (1 pt/A) + Command 4EC (0.5 pt/A) was made the day before planting for weed control. Fertilizer (0-45-0 @ 150 lb/A) was applied with the seed at planting. Asana XL (9.6 oz/A) was applied to plants on 16 and 25 May for Sitona lineatus (pea leaf weevil) control. Total precipitation 3 May - 11 Jul was 3.57 in., and average maximum and minimum temperatures were 64.8 and 49.6o F, respectively. Emergence was taken on 26 May and plant height on 26 May, and 2, 9 and 15 Jun. Root rot was evaluated on 24 Jun and 11 Jul. Fresh pea yield was taken on 15 Jul when tenderometer (tenderness measured by a Food Technology Corp. Texture-Gage 4B) readings approximated 105; plants were cut and threshed from the middle 3.3 ft.2 mid-section of each plot, pods were counted and weighed, and then the peas from 100 pods were also weighed. All treatment comparisons were by analysis of variance (SAS, Cary, NC). Emergence was significantly higher for Allegiance + Captan, Phostrol in-furrow and Phostrol in-furrow + emergence compared to the other treatments. Similarly, AUPHPC was highest for Allegiance + Captan, Phostrol in-furrow and Phostrol in-furrow + emergence treatments compared to other treatments. Initial root rot ratings on 24 Jun were not significantly different among treatments although the Phostrol in-furrow + emergence treatment had the lowest root rot index. Conversely, final root rot ratings prior to harvest were significantly higher for Phostrol in-furrow and Phostrol in-furrow + emergence than the non-treated control. Allegiance + Captan, Phostrol in-furrow and Phostrol in-furrow + emergence treatments had significantly higher yields than all biological treatments (GB 34, Heads Up 1 and 2, Kodiak, Micro 108 and T-22 Planter Box) except for Serenade ASO. When adjusted for 105T, green pea yields for the Phostrol in-furrow and Phostrol in-furrow + emergence treatments were significantly higher than all treatments except for Captan + Allegiance, Phostrol at emergence + 14 days and Serenade ASO treatments. T-22 Planter Box treatment had the lowest yield followed by Heads Up 1 and Micro 108 treatments which had lower adjusted yields than the non-treated control. Among the biologicals, emergence, AUPHPC, root rot and yield were similar although Serenade ASO was one of the highest yielding treatments in the trial. In-furrow and foliar applications of Phostrol present a promising alternative for pea production in northwestern Washington.