Management of seedling diseases caused by Oomycetes, Phytophthora spp., Phytopythium spp. and Pythium spp. using seed treatment in Ohio.

Bibliographic Details
Main Author:	Vargas, Amilcar
Language:	English
Published:	The Ohio State University / OhioLINK 2018
Subjects:	Agricultural Chemicals Agriculture Agronomy Plant Pathology Watermolds Pythium Phytophthora Phytopythium
Online Access:	http://rave.ohiolink.edu/etdc/view?acc_num=osu1524060260234098

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spelling	ndltd-OhioLink-oai-etd.ohiolink.edu-osu15240602602340982021-08-03T07:06:16Z Management of seedling diseases caused by Oomycetes, <i>Phytophthora</i> spp., <i>Phytopythium</i> spp. and <i>Pythium</i> spp. using seed treatment in Ohio. Vargas, Amilcar Agricultural Chemicals Agriculture Agronomy Plant Pathology Watermolds Pythium Phytophthora Phytopythium Watermolds that affect soybean seed and seedlings contribute to significant losses each year due to reduced plant population and yield. In Ohio, <i>Pythium</i> and <i>Phytophthora</i> populations are diverse, with more than 30 species of <i>Pythium</i> being recovered from symptomatic soybean seedlings. This includes species of <i>Pythium</i> that were recently reclassified as <i>Phytopythium</i>. Fungicide seed treatments and host resistance are the main strategies to manage seedling diseases caused by watermolds in Ohio. The reduced sensitivity of watermold populations towards the current active ingredients in the market has led to an increased interest to identify and evaluate new active ingredients. The objectives of this study were to evaluate the efficacy of oxathiapiprolin alone or in combination with metalaxyl/mefenoxam or ethaboxam as a soybean seed treatment and the pathogenicity of <i>Phytopythium mercuriale</i> on three soybean cultivars with different levels of resistance towards watermolds.Oxathiapiprolin was evaluated through lab, greenhouse, and field-based studies at 14 different environments across Ohio. In amended agar plates inoculated with different species of watermolds, oxathiapiprolin significantly limited mycelial growth of <i>Phytopythium helicoides</i>, <i>Phy. litorale</i>, <i>Phytopythium delawarense</i>, <i>Phy. mercuriale</i>, <i>Phytophthora sojae</i> and <i>Phytophthora sansomeana</i>, but not <i>Pythium torulosum</i>, <i>Py. ultimum</i> var. <i>ultimum</i>, <i>Py. lutarium</i>, <i>Py. attrantheridium</i>, <i>Py. inflatum</i>, <i>Py. oopapillum</i>, <i>Py. diclinum</i>, <i>Py. pleroticum</i>, <i>Py. heterothallicum</i>, <i>Py. nodosum</i>, <i>Py. middletonii</i> and <i>Py. dissotocum</i>. In a greenhouse cup assay, there was no significant difference between the non-treated and seed treated with oxathiapiprolin (P > 0.05) that was inoculated with <i>Pythium</i> spp. In field based studies there was a significantly higher number of plants per hectare in 5 of 10 environments and yield (kg/ha) in 6 of 10 environments when seed of a moderately susceptible cultivar was treated with oxathiapiprolin alone or in combination with metalaxyl/mefenoxam or ethaboxam. Early plant population and yield (kg/ha) were also significantly (P < 0.05) higher for 6 of 7 cultivars in at least 1 of 4 environments. These results indicate that oxathiapiprolin can be used to protect soybean plant establishment and yield in regions prone to heavy rains shortly after planting where diseases caused by <i>Phytophthora</i> and <i>Phytopythium</i> are prevalent. Care should be taken to combine oxathiapiprolin with another active ingredient targeting species of <i>Pythium</i>.Based on a seed plate and seedling root rot experiments, <i>Phytopythium mercuriale</i> isolates collected in Ohio, significantly inhibited germination, reduced seed health, and caused seedling root rot on soybean. Based on the distribution in North America including, Arkansas, Kansas, Nebraska, Ontario and now Ohio, this is a specie that requires more evaluation and most likely has a wider distribution and host range. 2018-08-15 English text The Ohio State University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=osu1524060260234098 http://rave.ohiolink.edu/etdc/view?acc_num=osu1524060260234098 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.
collection	NDLTD
language	English
sources	NDLTD
topic	Agricultural Chemicals Agriculture Agronomy Plant Pathology Watermolds Pythium Phytophthora Phytopythium
spellingShingle	Agricultural Chemicals Agriculture Agronomy Plant Pathology Watermolds Pythium Phytophthora Phytopythium Vargas, Amilcar Management of seedling diseases caused by Oomycetes, <i>Phytophthora</i> spp., <i>Phytopythium</i> spp. and <i>Pythium</i> spp. using seed treatment in Ohio.
author	Vargas, Amilcar
author_facet	Vargas, Amilcar
author_sort	Vargas, Amilcar
title	Management of seedling diseases caused by Oomycetes, <i>Phytophthora</i> spp., <i>Phytopythium</i> spp. and <i>Pythium</i> spp. using seed treatment in Ohio.
title_short	Management of seedling diseases caused by Oomycetes, <i>Phytophthora</i> spp., <i>Phytopythium</i> spp. and <i>Pythium</i> spp. using seed treatment in Ohio.
title_full	Management of seedling diseases caused by Oomycetes, <i>Phytophthora</i> spp., <i>Phytopythium</i> spp. and <i>Pythium</i> spp. using seed treatment in Ohio.
title_fullStr	Management of seedling diseases caused by Oomycetes, <i>Phytophthora</i> spp., <i>Phytopythium</i> spp. and <i>Pythium</i> spp. using seed treatment in Ohio.
title_full_unstemmed	Management of seedling diseases caused by Oomycetes, <i>Phytophthora</i> spp., <i>Phytopythium</i> spp. and <i>Pythium</i> spp. using seed treatment in Ohio.
title_sort	management of seedling diseases caused by oomycetes, <i>phytophthora</i> spp., <i>phytopythium</i> spp. and <i>pythium</i> spp. using seed treatment in ohio.
publisher	The Ohio State University / OhioLINK
publishDate	2018
url	http://rave.ohiolink.edu/etdc/view?acc_num=osu1524060260234098
work_keys_str_mv	AT vargasamilcar managementofseedlingdiseasescausedbyoomycetesiphytophthoraisppiphytopythiumisppandipythiumisppusingseedtreatmentinohio
_version_	1719453712133390336

Management of seedling diseases caused by Oomycetes, <i>Phytophthora</i> spp., <i>Phytopythium</i> spp. and <i>Pythium</i> spp. using seed treatment in Ohio.

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