Standorteigenschaften und Anbaumanagement erklären regionale Unterschiede im Kohlherniebefall in Deutschland

Abstract

Befallsintensitäten aufwiesen. In unserer Untersuchung beeinflussten die Bodenart, der Sandgehalt sowie der BodenpH-Wert das Vorkommen von P. brassicae. Bodenarten mit Sandgehalten von 30 bis 35 % und niedrigen BodenpH-Werten von unter 5,6 korrelierten auf den untersuchten Praxisschlägen mit hohen Befallsintensitäten. Schlüsselwörter Regionales Auftreten · Einflussfaktoren · Brassica napus · WinterrapsAbstract In the years 2013 and 2014 the presence and the infestation level of Plasmodiophora brassicae in six federal states of Germany were assessed using a bioassay method. Soils were sampled from 237 oilseed rape fields and the farmers provided information about the soil type, the soil pH values and the last year of oilseed rape cultivation. Clubroot was detected in 66 % of the fields investigated with a mean disease severity (BI) of 0.34. Between and within the federal states differences in presence and infestation level of P. brassicae were detected. In Schleswig-Holstein significantly more fields were infected by P. brassicae (90 %) and BI was relatively high (0.49) compared to Lower Saxony, Mecklenburg-Western Pomerania and North Rhine-Westphalia with 50 % infected fields and a mean BI of 0.27. Highly infested fields (BI > 0.8) were prevalent on 15 and 25 % of fields investigated in every federal state. Within the federal states the soil climate regions (BKR) differed significantly from each other. In BKR with light and sandy soils P. brassicae was less widespread compared to neighboring BKR with loamy soils. In addition, BKR with high infestation levels on fields invesZusammenfassung Um die Verbreitung und die Befallsintensität von Plasmodiophora brassicae in Deutschland zu erfassen, wurden in den Jahren 2013 und 2014 Bodenproben von insgesamt 237 Rapsflächen in sechs Bundesländern mit Hilfe eines Biotests untersucht. Durch Befragung der Landwirte wurden der Boden-pH-Wert, die Bodenart und das letzte Rapsanbaujahr der Untersuchungsstandorteerhoben. Insgesamt waren 66 % der untersuchten Flächen mit Kohlhernie befallen, und der mittlere Befallsindex lag bei 0,34. Signifikante Unterschiede im Pathogenauftreten und in der Befallsintensität traten sowohl zwischen als auch innerhalb der untersuchten Bundesländer auf. In Schleswig-Holstein waren 90 % der untersuchten Flächen mit Kohlhernie befallen und der mittlere Befallsindex lag bei 0,49. In Mecklenburg-Vorpommern, Niedersachsen und Nordrhein-Westfalen waren ca. 50 % der beprobten Flächen mit Kohlhernie befallen und hatten einen mittleren Befallsindex von 0,27. Der Anteil der Flächen mit einem sehr hohen Befallsindex von über 0,8 lag in allen untersuchten Bundesländern zwischen 15 und 25 %. Innerhalb der Bundesländer unterschieden sich die Bodenklimaräume (BKR) signifikant im Pathogenauftreten und der Befallsintensität: Die untersuchten Flächen der BKR, in denen leichte Sandböden dominieren, wie z. B. das Landesinnere von Mecklenburg-Vorpommern und die Geestböden in Schleswig-Holstein, wiesen mehr befallsfreie Fläche auf als die besseren diluvialen Böden in angr...

Variation in pathotypes and virulence of Plasmodiophora brassicae populations in Germany

“…This observation is in agreement with a recent study by Strehlow et al . (). In their study, 66% of 237 farm fields investigated using a bioassay of soil samples showed clubroot infestation, with a mean disease severity of 34%.…”

“…However, the populations of the pathogen used in the present study were not single‐spore isolates and this may have resulted in the differences observed. Previously confirmed Mendel resistance‐breaking isolates originated from the Lower Saxony, Saxony, Hesse, Bavaria, West German Emsland and Westphalia regions (Strehlow et al ., ). The present investigation also found virulent isolates in Baden Würtemberg, Rhineland‐Palatinate and Thuringia.…”

“…These results are in close agreement with Strehlow et al . () who showed infestation levels were significantly influenced by soil type, content of sand and soil pH; soil with a sand content of 30–35% and pH < 5.6 showed high clubroot severity and disease incidence. Wallenhammar () showed that the highest levels of clubroot often appeared in soils with the lowest soil organic matter and that clubroot was mostly detected in fields with higher quantities of clay or silt particles.…”

Transcriptome Analysis of Arabidopsis thaliana in Response to Plasmodiophora brassicae during Early Infection

“…Clubroot has been reported in more than 60 countries or regions around the world, and, in recent years, the disease has become increasingly serious. In Europe, North America, East Asia, and other regions, clubroot has become a major threat (Dixon, 2009; Chittem et al, 2014; Galdames et al, 2014; Strehlow et al, 2014; Wallenhammar et al, 2014; Strelkov et al, 2016). …”

Reducing the build‐up of Plasmodiophora brassicae inoculum by early management of oilseed rape volunteers

“…Clubroot of oilseed rape ( Brassica napus ; OSR), caused by an obligate biotroph pathogen Plasmodiophora brassicae , is a destructive disease and an emerging threat to German OSR production (Lüders et al ., ; Diederichsen et al ., ; Strehlow et al ., ; Zamani‐Noor, ). Differences in clubroot disease incidence and severity were observed among German Federal States due to the differences in the pathotype complex, OSR genotypes, regional weather conditions and agricultural practices (Strehlow et al ., ; Zamani‐Noor, ).…”