The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform

Maja Ravnikar - One of the best experts on this subject based on the ideXlab platform.

  • Elimination of Bean Seed-Borne Bacteria by Thermotherapy and Meristem Culture
    Plant Cell Tissue and Organ Culture, 1997
    Co-Authors: Mateja Grum, Marjana Camloh, Klaus Rudolph, Maja Ravnikar
    Abstract:

    Common and halo blights caused by Xanthomonas campestris pv. phaseoli, and Pseudomonas syringae pv. phaseolicola, respectively, are major world-wide Seed-Borne Diseases of bush bean (Phaseolus vulgaris L.) [1], Seeds contaminated either internally or externally constitute the primary source of the inoculum. In annual plants the main mode of bacterial disease transmission is via the seeds.

Anders Borgen - One of the best experts on this subject based on the ideXlab platform.

  • Novel development of heat treatment techniques for seed surface sterilisation
    2005
    Co-Authors: Anders Borgen, Niels Krebs, Carsten Langkjaer
    Abstract:

    Heat treatment to prevent seed borne Diseases, e.g. in the form of hot water or warm humid air, will normally heat up the entire seed. Heat treatment of the seed embryo will always have a negative side-effect on seed vigour and the duration of several minutes are difficult to implement in seed plans treating huge volumes of seed. However, in the case of common bunt in wheat and similar Diseases, where the inoculum is transmitted as fungal spores on the surface of the seed, an uniform and efficient surface sterilisation will be sufficient to prevent the transmission of the disease. To test the effect of surface heat sterilisation of seed, an equipment was developed, where seeds were exposed to a combination of steam and ultrasound. The principle is that the ultrasound will create a fluctation of the air molecules in the chamber, and thereby increase the access of the hot steam to the surface of the seed. In this equipment, common bunt in wheat was eliminated after 4 sec. treatment and in spelt after 8 seconds. A 16 times increase of the duration of the treatment did not decrease germination speed of the seed, tested in a cold sand test. This demonstrates that surface transmitted Diseases can be controlled efficiently and environmentally friendly by equipment adaptable to commercial seed plans.

  • Strategies for regulation of seed borne Diseases in organic farming
    2004
    Co-Authors: Anders Borgen
    Abstract:

    Common bunt caused by the fungus Tilletia tritici (syn. T.caries) is one of the most devastating plant Diseases in wheat. In conventional agriculture the disease is controlled exclusively by fungicide seed treatment, but in organic farming these fungicides are not accepted. Previous studies in India have shown that seed treatment with plant extracts of Canabis sativa, Eucalyptus globulus, Thuja sinensis and Datura stramonium was fully effective against the disease under field conditions. Later, in vitro studies have shown that also germination of spores of the Karnal bunt pathogen (Neovossia indica) could be prevented by these plant extracts. The experiment was repeated in Denmark with extracts from the same species grown in Denmark, which has climate conditions very different from India. In this experiment the same seed treatments had no or very limited effect on the frequency of the disease. The treatments were compared with indigenous methods from Europe including salty brine, Thuja leaves and lime. These methods had a significant but insufficient effect on disease suppression.

  • Control of seed borne Diseases in organic cereals and legumes
    2002
    Co-Authors: Anders Borgen
    Abstract:

    In Denmark, most organic farmers uses organic propagated cereals and legumes for seeding, and all seed lots are tested for infections of seed borne pathogens before sowing. About 50% of all see lots are discarded based on this assessment, but huge differences occur between year and crop, which makes planning of seed production impossible. Some years up to 90% of the seed lots of a crop may be discarded e.g. peas in year 2000. The major cause of this are: Tilletia tritici in wheat, Dreschlera graminea, D. teres and Ustilago nuda in barley, Fusarium spp in triticale, and Ascochyta spp in peas. This situation calls for research focusing on this specific problem in the organic plant production. Research in organic seed production, handling and use started 10 years ago in Denmark, and the current research programme will continue until 2005. The strategy now in development of organic control measures will focus on preventive measures to minimize the infection in field during propagation. This includes investigation of the effect of harvest time, sowing time, crop density and crop mixtures. Varieties will be tested for specific resistance to the major systemic pathogens. However, also development of seed treatment are needed, and the current effort will investigate the effect of seed size separation, seed density separation to control D. graminea , D. teres, U. nuda and Fusarium spp. Brush cleaning will be developed to control T. tritici and Urocystis occulta. Water-free heat treatment will be developed to control a range of seed pathogens. In combination with development of more precise detection methods using PCR technology, and evaluation of the thresholds used for assessment of seed quality, it is the hope to minimize the number of seed lots discarded because of seed borne pathogens in organic agriculture.

  • Effect of seed treatment with acetic acid in control of seed borne Diseases
    2001
    Co-Authors: Anders Borgen, Bent Nielsen
    Abstract:

    In field trials, seed treatment with acetic acid has reduced common bunt (Tilletia tritici) in winter wheat by 91.5-96.2% and by 83% in spring wheat without negative effects on germination vigour of the seeds. Leaf stripe (Pyrenophora graminea) in spring barley was reduced by 93,4%. Acetic acid is a cheap and environmental friendly fungicide with a possible scope of application especially in organic agriculture, where conventional pesticides are prohibited.

  • Seed borne Diseases - a challenge for organic cereal production
    2000
    Co-Authors: Anders Borgen, Lars Kristensen
    Abstract:

    Seed borne Diseases are to be considered serious in organic agriculture, and direct seed treatment methods will some times be necessary. Hot water treatment, mustard extracts and acetic acid can provide efficient control methods. Discussions on the feasibility of the different methods in organic agriculture is needed.

Mateja Grum - One of the best experts on this subject based on the ideXlab platform.

  • Elimination of Bean Seed-Borne Bacteria by Thermotherapy and Meristem Culture
    Plant Cell Tissue and Organ Culture, 1997
    Co-Authors: Mateja Grum, Marjana Camloh, Klaus Rudolph, Maja Ravnikar
    Abstract:

    Common and halo blights caused by Xanthomonas campestris pv. phaseoli, and Pseudomonas syringae pv. phaseolicola, respectively, are major world-wide Seed-Borne Diseases of bush bean (Phaseolus vulgaris L.) [1], Seeds contaminated either internally or externally constitute the primary source of the inoculum. In annual plants the main mode of bacterial disease transmission is via the seeds.

Marijan Jost - One of the best experts on this subject based on the ideXlab platform.

  • effect of stone meal on control of seed borne Diseases in wheat
    Agronomy Journal, 2008
    Co-Authors: Vesna Samobor, Dijana Horvat, Branko Kesteli, Marijan Jost
    Abstract:

    In organic seed production more than a half of seed lots are often discarded due to heavy infection with seed borne pathogens. To prevent this, various techniques are used: seed heat treatment, ultrasound treatment, brush cleaning and seed dressing with plant extracts or natural chemicals. In 2008, the efficiency of wheat seed treatment with the stone meal was tested and the results of preliminary investigation are presented. Two tests were performed using the official procedure for seed health testing. Test 1: Heavily infected wheat seed was treated with the stone meal EKORAST (particle size <0.08 mm). Dry and wet treatment procedures were applied: both with 1, 2, 10 and 20%. Heavy application (10 and 20 kg per 100 kg of seed) significantly increased germination and energy of wheat seed, and it was effective against bacterial pathogens and some fungi, but only partially effective against heavy infection of Fusarium spp. However, the amounts of stone meal (10 and 20%) are practically not applicable, and adhesion of stone meal to the seed should be improved. Test 2: Wheat cleaned seed of seven genotypes was wet treated with Ekorast (1 %) and chemical fungicide Vitavax 200FF (250 ml/100 kg). The untreated seed was used as control. There were no significant differences between the three variants in germination and energy. The stone meal Eko-rast was equal or better than Vitavax 200FF in seed protection against seed borne pathogens, and could be recommended for seed treatment in organic seed production. Search for an additive with better adhesion to seed is under way.

  • Effect of stone meal on control of Seed-Borne Diseases in wheat
    Agronomy Journal, 2008
    Co-Authors: Vesna Samobor, Dijana Horvat, Branko Kesteli, Marijan Jost
    Abstract:

    In organic seed production more than a half of seed lots are often discarded due to heavy infection with seed borne pathogens. To prevent this, various techniques are used: seed heat treatment, ultrasound treatment, brush cleaning and seed dressing with plant extracts or natural chemicals. In 2008, the efficiency of wheat seed treatment with the stone meal was tested and the results of preliminary investigation are presented. Two tests were performed using the official procedure for seed health testing. Test 1: Heavily infected wheat seed was treated with the stone meal EKORAST (particle size

Bent Nielsen - One of the best experts on this subject based on the ideXlab platform.

  • Effect of seed treatment with acetic acid in control of seed borne Diseases
    2001
    Co-Authors: Anders Borgen, Bent Nielsen
    Abstract:

    In field trials, seed treatment with acetic acid has reduced common bunt (Tilletia tritici) in winter wheat by 91.5-96.2% and by 83% in spring wheat without negative effects on germination vigour of the seeds. Leaf stripe (Pyrenophora graminea) in spring barley was reduced by 93,4%. Acetic acid is a cheap and environmental friendly fungicide with a possible scope of application especially in organic agriculture, where conventional pesticides are prohibited.

  • Control of seed borne Diseases in production of organic cereals
    2000
    Co-Authors: Bent Nielsen, Anders Borgen, Lars Kristensen
    Abstract:

    In production of organic seed it is important to have some control measures on seed borne Diseases to avoid propagation and spread of serious Diseases. Due to lack of acceptable treatment methods the only way for the moment is to discard seed lots with unacceptable infections. Experiments have been started to find new and alternative methods for controlling seed borne Diseases. In spring barley the results show good effect with 5% acetic acid on leaf stripe (Pyrenophora graminea) but problems with unacceptable effects on seed germination have to be solved. The old method with hot water treatment can be used and the results indicate good results against leaf stripe using water at 55°C. The effect of hot water was enhanced by first soaking the seeds in water at 20°C. Controlling loose smut (Ustilago nuda) is more complicated and here pre treatment with soaking seeds in water at 45°C succeeded by short treatment in water at 50°C gave good results.

  • Strategies for controlling Seed-Borne Diseases in cereals and possibilities for reducing fungiside seed treatments
    1998
    Co-Authors: Bent Nielsen, Anders Borgen, Ghita Nielsen, Christiane Shceel
    Abstract:

    In the short term there is no useful alternative to chemical seed treatment for controlling the important Seed-Borne Diseases in cereals. The only way to secure high quality seed is by discarding seed lots which have more than a specified level of disease. Without any other effective control measure than seed treatment large quantities of cereal seeds would be expected to be discarded. Another reduction model might be a differentiated use of seed treatments in the different certified seed generations. An important condition for the models is a representative seed test which for the moment only is possible in spring cereals. The threshold levels for the different Diseases should under these circumstances be re-evaluated. In the long term other measurements may be possible. Investigations have begun on variety resistance to demonstrate effective genetic resistance against leaf stripe and common bunt, but for the moment only little is known on the distribution of resistance in modern Danish varieties. Other possibilities may be microbiological products and non-chemical methods but also here further investigation is required