<abstract xml:lang="en" xmlns="http://www.w3.org/1999/xhtml">This study was carried out to investigate the toxic effects of the fungicide thiram (TMTD) against five nitrogen fixers and the thiram target pest <italic>Fusarium oxysporum</italic> under laboratory conditions. Nitrogen fixing bacteria <italic>Falvobacterium</italic> showed the highest values of LD50 and proved to be the most resistant to the fungicide followed by <italic>Fusarium oxysporum</italic>, while <italic>Pseudomonas aurentiaca</italic> was the most affected microorganism. LD50 values for these microorganisms were in 2-5 orders of magnitude lower in comparison with LD50 value for <italic>Fusarium oxysporum</italic>. Thiram was most toxic to <italic>Pseudomonas aurentiaca</italic> followed by <italic>Azospirillum</italic>. The lowest toxicity index was recorded for <italic>Fusarium oxysporum</italic> and <italic>Flavobacterium</italic>. The slope of the curve for <italic>Azomonas, Fusarium oxysporum</italic> and <italic>Flavobacterium</italic> is more steep than that of the other curves, suggesting that even a slight increase of the dose of the fungicide can cause a very strong negative effect. Thiram was more selective to <italic>Pseudomonas aurentiaca</italic> followed by <italic>Azospirillum, Rhizobium meliloti</italic> and <italic>Azomonas</italic>. The lowest selectivity index of the fungicide was recorded for <italic>Falvobacterium</italic> followed by <italic>Fusarium oxysporum</italic>. The highest safety coefficient of the fungicide was assigned for <italic>Flavobacterium</italic>, while <italic>Pseudomonas aurentiaca</italic> showed the lowest value.</abstract>

This study was carried out to investigate the toxic effects of the fungicide thiram (TMTD) against five nitrogen fixers and the thiram target pest Fusarium oxysporum under laboratory conditions. Nitrogen fixing bacteria Falvobacterium showed the highest values of LD50 and proved to be the most resistant to the fungicide followed by Fusarium oxysporum, while Pseudomonas aurentiaca was the most affected microorganism. LD50 values for these microorganisms were in 2-5 orders of magnitude lower in comparison with LD50 value for Fusarium oxysporum. Thiram was most toxic to Pseudomonas aurentiaca followed by Azospirillum. The lowest toxicity index was recorded for Fusarium oxysporum and Flavobacterium. The slope of the curve for Azomonas, Fusarium oxysporum and Flavobacterium is more steep than that of the other curves, suggesting that even a slight increase of the dose of the fungicide can cause a very strong negative effect. Thiram was more selective to Pseudomonas aurentiaca followed by Azospirillum, Rhizobium meliloti and Azomonas. The lowest selectivity index of the fungicide was recorded for Falvobacterium followed by Fusarium oxysporum. The highest safety coefficient of the fungicide was assigned for Flavobacterium, while Pseudomonas aurentiaca showed the lowest value.

Sensitivity of some nitrogen fixers and the target pest <italic>Fusarium oxysporum</italic> to fungicide thiram

Biofertilization Department, Environment and Natural Resource Research Institute, National Center for Research, Sudan

Botany Department, Faculty of Science, University of Khartoum, Khartoum, Sudan

Interdisciplinary Toxicology

Sensitivity of some nitrogen fixers and the target pest  to fungicide thiram

This study was carried out to investigate the toxic effects of the fungicide thiram (TMTD) against five nitrogen fixers and the thiram target pest Fusarium...

Sensitivity of some nitrogen fixers and the target pest Fusarium oxysporum to fungicide thiram

Published Online: May 11, 2012

Page range: 25 - 29

DOI: https://doi.org/10.2478/v10102-012-0005-6

Keywords
nitrogen fixers, fusarium oxysporum, thiram, toxicology

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