Journal of Plant Diseases and Protection (2012) 119, 85-91
Jan Nechwatal and Jürgen Leiminger (2012)
Evidence for the involvement of Aphanomyces cochlioides and Pythium spp. in 'girth scab' disease of sugar beet in Bavaria
Journal of Plant Diseases and Protection 119 (3), 85-91
Abstract: The term 'girth scab' describes a chronic disease of sugar beet roots (Beta vulgaris ssp. vulgaris) for which the causes still remain unclear. While pathogenicity of the oomycete Aphanomyces cochlioides to sugar beet has been known for along time, most practical guides and other professional literature refer to actinobacteria as the causal agents. In this study, we try to provide some clarification of the aetiologyof this disease by studying affected sugar beets from different regions in Bavaria, with a focus on the involvement of A. cochlioides and other soilborne oomycetes. In parallel, the samples were investigated for the presence of actinobacteria. A. cochlioides and several Pythium spp. were isolated from the samples in both 2010 and 2011, among these P. recalcitrans , P. intermedium and P. sylvaticum . In a soil infestation test, A. cochlioides in particular proved to be highly aggressive to young beet plants, causing severe symptoms of 'girthscab', and a significant biomass reduction. P. recalcitrans also caused mild scab, while the other species led to biomass reductiononly. Bacteriological studies showed that Streptomyces spp. found on some samples were most likely non-pathogenic strains that were not primarily involved in the disease. Our results show that A. cochlioides rather than actinobacteria is most probably the causal agent of the 'girth scab' disease. The wet weather conditions and the massive occurrence in 2010 make the contribution of this moisture-associated oomycete most plausible. The role of several Pythium spp. that caused similar symptoms remains to be clarified.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Jan Nechwatal, Jürgen H. Leiminger
Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution
Pest and/or beneficial records:
| Beneficial | Pest/Disease/Weed | Crop/Product | Country | Quarant.
|
|---|---|---|---|---|
| Aphanomyces cochlioides | Beet/sugarbeet (Beta vulgaris) | Germany | ||
| Globisporangium intermedium | Beet/sugarbeet (Beta vulgaris) | Germany | ||
| Globisporangium sylvaticum | Beet/sugarbeet (Beta vulgaris) | Germany | ||
| Pythium recalcitrans | Beet/sugarbeet (Beta vulgaris) | Germany |
