Efficacy of mefenoxam is affected by a lag period between application and inactivation of <em>Pythium</em> species

A study was undertaken to investigate whether inactivation of Pythium by mefenoxam takes place as soon as it comes in contact with the fungicide. Laboratory experiments were conducted which involved three sensitive isolates of P. aphanidermatum (EC50<1 µg mL-1), three sensitive isolates of P. spi...

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Main Author: Abdullah AL-SADI
Format: Article
Language:English
Published: Firenze University Press 2012-08-01
Series:Phytopathologia Mediterranea
Subjects:
Online Access:https://oajournals.fupress.net/index.php/pm/article/view/5484
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author Abdullah AL-SADI
author_facet Abdullah AL-SADI
author_sort Abdullah AL-SADI
collection DOAJ
description A study was undertaken to investigate whether inactivation of Pythium by mefenoxam takes place as soon as it comes in contact with the fungicide. Laboratory experiments were conducted which involved three sensitive isolates of P. aphanidermatum (EC50<1 µg mL-1), three sensitive isolates of P. spinosum (EC50<1 µg mL-1) and two resistant isolates of P. aphanidermatum (EC50>100 µg mL-1). In liquid cultures, inactivation of the sensitive Pythium isolates by mefenoxam took place between 12 hr and >96hr at concentrations from 1 to 100 µg mL-1. The time required for inactivation was negatively correlated with the concentration of mefenoxam (P<0.05). Colonization of cucumber seeds placed at different distances from the sensitive Pythium inoculum in soil amended with 1 and 5 µg mL-1 mefenoxam occurred in the first 12 hr. However, colonization was reduced after 24 hr and was completely inhibited after 96 hr. Efficiency of colonization in the sensitive Pythium populations was found to have a negative correlation with the concentration of mefenoxam used. Growth and colonization by the resistant Pythium isolates were not found to be affected with mefenoxam. This study appears to be the first report of presence of a lag period between application of mefenoxam and time taken to inactivate Pythium.
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spelling doaj.art-d726f457a8824925970be4f3f4ac48752022-12-21T20:45:15ZengFirenze University PressPhytopathologia Mediterranea0031-94651593-20952012-08-0151210.14601/Phytopathol_Mediterr-962510125Efficacy of mefenoxam is affected by a lag period between application and inactivation of <em>Pythium</em> speciesAbdullah AL-SADIA study was undertaken to investigate whether inactivation of Pythium by mefenoxam takes place as soon as it comes in contact with the fungicide. Laboratory experiments were conducted which involved three sensitive isolates of P. aphanidermatum (EC50<1 µg mL-1), three sensitive isolates of P. spinosum (EC50<1 µg mL-1) and two resistant isolates of P. aphanidermatum (EC50>100 µg mL-1). In liquid cultures, inactivation of the sensitive Pythium isolates by mefenoxam took place between 12 hr and >96hr at concentrations from 1 to 100 µg mL-1. The time required for inactivation was negatively correlated with the concentration of mefenoxam (P<0.05). Colonization of cucumber seeds placed at different distances from the sensitive Pythium inoculum in soil amended with 1 and 5 µg mL-1 mefenoxam occurred in the first 12 hr. However, colonization was reduced after 24 hr and was completely inhibited after 96 hr. Efficiency of colonization in the sensitive Pythium populations was found to have a negative correlation with the concentration of mefenoxam used. Growth and colonization by the resistant Pythium isolates were not found to be affected with mefenoxam. This study appears to be the first report of presence of a lag period between application of mefenoxam and time taken to inactivate Pythium.https://oajournals.fupress.net/index.php/pm/article/view/5484cucumber
spellingShingle Abdullah AL-SADI
Efficacy of mefenoxam is affected by a lag period between application and inactivation of <em>Pythium</em> species
Phytopathologia Mediterranea
cucumber
title Efficacy of mefenoxam is affected by a lag period between application and inactivation of <em>Pythium</em> species
title_full Efficacy of mefenoxam is affected by a lag period between application and inactivation of <em>Pythium</em> species
title_fullStr Efficacy of mefenoxam is affected by a lag period between application and inactivation of <em>Pythium</em> species
title_full_unstemmed Efficacy of mefenoxam is affected by a lag period between application and inactivation of <em>Pythium</em> species
title_short Efficacy of mefenoxam is affected by a lag period between application and inactivation of <em>Pythium</em> species
title_sort efficacy of mefenoxam is affected by a lag period between application and inactivation of em pythium em species
topic cucumber
url https://oajournals.fupress.net/index.php/pm/article/view/5484
work_keys_str_mv AT abdullahalsadi efficacyofmefenoxamisaffectedbyalagperiodbetweenapplicationandinactivationofempythiumemspecies