Changes of tomato rhizosphere microflora following application of the herbicide diphenamid to soil infested withFusarium oxyspommf.sp.lycopersici
✍ Scribed by M. S. El-Abyad; M. Ghareeb
- Publisher
- Springer Netherlands
- Year
- 1991
- Tongue
- English
- Weight
- 505 KB
- Volume
- 113
- Category
- Article
- ISSN
- 0301-486X
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✦ Synopsis
Significant variations were detected in species composition between untreated rhizosphere and nonrhizosphere soils of tomato plants. Application of different concentrations of active ingredient of the herbicide diphenamid (5-250 ppm) to these soils caused significant alterations in species assemblages as compared with untreated soils. Also variations in species composition were denoted between treated rhizosphere and non-rhizosphere soils.
Diphenamid concentrations of 10-100 ppm significantly affected microbial counts in soil and rhizosphere of tomato plants. Counts have been stimulated at diphenamid concentrations ranging from 10-50 ppm for fungi and 10-100 ppm for bacteria. At concentrations higher than the upper limits of these ranges, R/S values were not significantly affected.
The results also indicated that Fusarium oxysporum f.sp. lycopersici populations were unaffected by diphenamid at the recommended field rate (10 ppm). Above this concentration and within the conditions of the experiment, the pathogen maintained its population at detectable inocula. Population counts of Aspergillus candidus, a species reported to be able to degrade diphenamid, were high in both treated rhizosphere and non-rhizosphere soils.