Fusarium avenaceum - Fuß- und Wurzelkrankheitserreger der Erbse

Root and foot rot is economically important disease of peas and is caused by complex of more than 20 different species of soil-borne pathogens. In recent years in Germany, Fusarium avenaceum is emerging as important and devastating pathogen and it is together with several other species, including F. solani, F. oxysporum, F. redolens and Phoma medicaginis among the casual agents of the disease that is commonly referred to as pea root rot complex. In 2012, after severe black frost in February that caused failure of the pea crop, F. avenaceum was isolated in high percentage, 42% of assessed roots. All of tested F. avenaceum isolates caused moderate to severe disease symptoms on pea variety Santana. All of composts as well as endophytic F. equisety isolates were able to suppress the root rot disease caused by the F. avenaceum. The suppressive effect of composts was lost after -irradiation

A Novel Real Time PCR Method for the Detection and Quantification of Didymella pinodella in Symptomatic and Asymptomatic Plant Hosts

Didymella pinodella is the major pathogen of the pea root rot complex in Europe. This wide host range pathogen often asymptomatically colonizes its hosts, making the control strategies challenging. We developed a real-time PCR assay for the detection and quantification of D. pinodella based on the TEF-1 alpha gene sequence alignments. The assay was tested for specificity on a 54- isolate panel representing 35 fungal species and further validated in symptomatic and asymptomatic pea and wheat roots from greenhouse tests. The assay was highly consistent across separate qPCR reactions and had a quantification/detection limit of 3.1 pg of target DNA per reaction in plant tissue. Cross-reactions were observed with DNA extracts of five Didymella species. The risk of cross contamination, however, is low as the non-targets have not been associated with pea previously and they were amplified with at least 1000-fold lower sensitivity. Greenhouse inoculation tests revealed a high correlation between the pathogen DNA quantities in pea roots and pea root rot severity and biomass reduction. The assay also detected D. pinodella in asymptomatic wheat roots, which, despite the absence of visible root rot symptoms, caused wheat biomass reduction. This study provides new insights into the complex life style of D. pinodella and can assist in better understanding the pathogen survival and spread in the environament.info:eu-repo/semantics/publishedVersio

Screening verschiedener Leguminosenakzessionen auf ihre Anfälligkeit gegen wichtige Wurzelpathogene

Leguminous species could provide multiple beneficial services to agroecosystems when grown as cover crops (CC) and/or living mulch species (LM) in rotations with cereals. However, these benefits can only become effective if the pathological risks are thoroughly assessed and solutions for potential problems identified. In order to assess suitability for inclusion of novel leguminous LM and CC species into the rotations, a total of 62 accessions were screened under controlled conditions for their susceptibility/resistance to major legume root infecting pathogens. Majority of tested plant accessions were highly susceptible to Fusarium avenaceum, and low to moderately susceptible to F. oxysporum and F. solani. Peyronelaea pinodella and Didymella pinodes most severely affected Lathyrus accessions, otherwise infections were low

Anfälligkeit einer Sommererbse gegenüber Isolaten von Pathogenarten, die von symptomfreien Kleearten und Wicken isoliert wurden

Integration of additional leguminous living mulch and cover crop species holds a great potential for reducing external inputs and improving agricultural sustainability. However, changes towards legume rich crop rotations raises concerns as many of the species of interest share important soil-borne pathogens with some important main crops such as peas, beans and cereals. The pathogenicity towards the spring pea variety Santana was determined for 67 isolates of Fusarium oxysporum, F. solani, F. avenaceum, Didymella spp., Phoma medicaginis and Phoma spp. obtained from seemingly healhty roots of Trifolium subterraneum, T. repens, Vicia villosa and V. sativa. Only one isolate of F. solani and two isolates of Phoma spp. were nonpathogenic. F. avenaceum isolates were the most virulent with disease index up to 100 and reduction of fresh weights up to 98% compared with control plants

Aggressivität von Fusarium avenaceum, Fusarium solani f. sp pisi und Mycosphaerella pinodes auf Wintererbsen (Pisum sativum L.) unter kontrollierten Bedingungen

Climate change scenarios exhibit a definite warming trend (Schröter et al. 2005), and it will have an impact on crop management strategies. Increase in winter precipitation and higher temperatures favour soil borne pathogens and can lead to an increase in survival rate and to more rapid population buildup (Chakraborty et al. 2000). In recent years, one of the main reasons for declining production of summer pea in organic farming in Germany are foot and root rot pathogens (Pflughöft 2008). On the other hand, predicted increase in winter temperatures is expected to favour winter pea over summer pea varieties. The hope is also, that winter peas are less susceptible to root rot as summer peas. However, few data are available. The present study was carried out to evaluate the susceptibility of winter pea variety EFB 33 against different isolates of Fusarium avenaceum, Fusarium solani f. sp pisi and Mycosphaerella pinodes under controlled conditions in sterile sand. Three weeks after sowing and inoculation, disease symptoms were assessed and plant growth parameters measured. All of the tested pathogens caused root discoloration and development of disease symptoms on pea seedlings. F. avenaceum was the most aggressive pathogen causing severe wilting symptoms and highest reduction in fresh weight of pea. No significant differenceses in aggressivness between F. solani and M. pinodes were observed

Auswirkungen von Fusarium solani f. sp pisi, Fusarium avenaceum und Mycosphaerella pinodes auf Sommererbsen im Topfversuch

Foot rot is an important limiting factor in pea production in Germany (Pflughöft, 2008). The disease is caused by a pathogen complex consisting of Ascochyta complex pathogens (Mycospharella pinodes, Phoma medicaginis and Ascochyta pisi) and Fusarium spp. However, little is known about the specificity of single pathogens of the complex and their impact on plant performance. In order to address this problem pot experiments with five isolates each of Fusarium solani f.sp pisi, Fusarium avenaceum and Mycosphaerella pinodes were carried out in controlled conditions. Three weeks after sowing and inoculation disease symptoms were assessed and plant growth parameters measured. All pathogens caused root discoloration and development of disease symptoms on pea seedlings. However, there were significant differences in symptom severity and effects on plant performance. Fusarium avenaceum was the most aggressive pathogen causing severe wilting symptoms and high reduction in fresh weight of pea. Fusarium solani f.sp pisi was the second most aggressive pathogen, but did not significantly affected plant weight. On the other hand, symptoms due to inoculation with M. pinodes appeared less severe. Nevertheless, plant fresh weights were greatly reduced as a result of infection

Suppression of pathogens causing foot rot of pea by application of yard waste compost

Legume foot and root diseases are mostly caused by broad host-range pathogens. These cannot be managed by rotations alone as often cover crops also are susceptible. Organic amendments such as high quality composts are key management tools for dealing with pathogen pressure. A pot experiment under controlled conditions was carried out to evaluate the suppressive potential of Yard Waste Compost (YWC) against foot rot disease of pea caused by Mycosphaerella pinodes, Phoma medicaginis, Fusarium solani f. sp pisi and F. avenaceum. The spring pea Santana and winter pea EFB33 were grown in sterile sand or sand amended with 3.5 % or 20 % (v/v) YWC as a substrate for three weeks. They were either inoculated at sowing with spore suspensions or left uninoculated. Regardless of variety and pathogen, all application rates of compost significantly reduced the severity of foot rot

Shifts in the composition of plant parasitic nematodes under different tillage sytems, living mulch, and compost application

Plant parasitic nematodes may cause massive yield reductions in organic farming. Long rotations, often high amounts of weeds and a high frequency of legumes favour parasitic nematodes with a broad host range such as Meloidogyne spp. und Pratylenchus spp. The EU- Projekt OSCAR (Optimizing Subsidiary Crop Applications in Rotations) aims at improving soil conservation through minimum tillage combined with living mulches, cover crops and the use of suppressive composts. An experiment was set up with a rotation of 2-year grass-clover mix followed by wheat and then potatoes. Experimental factors were tillage, cover crops, and compost application. Until now Nematodes were sampled before and after wheat and before potatoes. Population dynamics over time were more affected by the time of the year than by the treatments applied. Sampling will continue will be presented Pratylenchus, Meloidogyne und Helicotylechus/Rotylenchus increased in the first year in all treatments. In the first half of the second year it appears that Meloidogyne has increased with no obvious effect of the treatments so far

A Novel Real Time PCR Method for the Detection and Quantification of Didymella pinodella in Symptomatic and Asymptomatic Plant Hosts

Didymella pinodella is the major pathogen of the pea root rot complex in Europe. This wide host range pathogen often asymptomatically colonizes its hosts, making the control strategies challenging. We developed a real-time PCR assay for the detection and quantification of D. pinodella based on the TEF-1 alpha gene sequence alignments. The assay was tested for specificity on a 54-isolate panel representing 35 fungal species and further validated in symptomatic and asymptomatic pea and wheat roots from greenhouse tests. The assay was highly consistent across separate qPCR reactions and had a quantification/detection limit of 3.1 pg of target DNA per reaction in plant tissue. Cross-reactions were observed with DNA extracts of five Didymella species. The risk of cross contamination, however, is low as the non-targets have not been associated with pea previously and they were amplified with at least 1000-fold lower sensitivity. Greenhouse inoculation tests revealed a high correlation between the pathogen DNA quantities in pea roots and pea root rot severity and biomass reduction. The assay also detected D. pinodella in asymptomatic wheat roots, which, despite the absence of visible root rot symptoms, caused wheat biomass reduction. This study provides new insights into the complex life style of D. pinodella and can assist in better understanding the pathogen survival and spread in the environment

Einflüsse des Ackerbohnenkäfers (Bruchus rufimanus) und von Bodenpathogenen auf Feldaufgang und Ertrag bei bunt- und weißblühenden Ackerbohnensorten (Vicia faba)

We compared field emergence and yield of a white- and a coloured-flowered variety of faba bean (Vicia faba) in relation to Bruchus rufimanus seed damage in a factorial, hand sown mini-plot field experiment. Further manipulating factors at sowing were, foot root rot inoculation with a 4-species Fusarium-mixture, a seed dressing with powdered testa material of the coloured-flower variety and sowing depth. In both varieties Fusarium-inoculation was the most detrimental and significant factor to field emergence and yield, interacting with a concordant B. rufimanus effect. Expectedly, the white-flowered variety was most affected. Tannin-containing testa meal did not reduce or compensate the impact of fungal inoculation and/or B. rufimanus. We hypothesize that B. rufimanus testa damage affects seedling vigour via reported faster water imbibition, causing cellular rupture and higher solute leakage which may enhance soilborne foot root rot incidence and finally yield. The results are discussed in the context of future research objectives