Vinegar can be used for seed treatment against common bunt in wheat. The effect and side effect depend on duration of the treatment rather than the dose.

In this video, plant breeder and common bunt researcher Anders Borgen from Agrologica (DK) addresses effective methods of seed cleaning and seed treatment to minimise the spread of common bunt spores, which is useful for organic farmers. He demonstrates the use of a seed brush to clean seeds with a machine he has modified himself for increased effectiveness. He also shows how to use vinegar as seed treatment within a mixer.

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

Common bunt (Tilletia tritici) infects the wheat plant during germination of the seed. For experiments with common bunt, it is conventional to examine symptoms of infection in the head of the plant. Previous research has advocated the possibility of scoring chlorosis on the leaf instead of head symptoms in order to reduce the duration of the experiment. By comparing the two diagnosis methods in climate chambers, the current experiment demonstrated that the sensitivity and specificity of the two methods depends on the wheat cultivar used. Using leaf symptoms as a diagnosis for infection has considerable disadvantages when used for screening for resistance in breeding programs, but have advantages, e. g., when investigating effects of seed treatments.

In field trials mustard flour was able to control seed borne infection by common bunt (Tilletia tritici) in wheat without decreasing the germination vigour of the treated seeds. Full control of common bunt by coating the seeds with milk powder could only be achieved at doses which reduced germination vigour of the seeds. Mustard flour can be recommended as a seed treatment in organic agriculture while a treatment based on milk powder should be developed in combination with biological control. Both milk powder and mustard flour can be used to control stem smut in rye (Urocystis occulta).

In field trials, seed treatment with acetic acid reduced common bunt (Tilletia tritici) by 92-96% in winter wheat, 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%. Acetic acid is a cheap and environmental friendly fungicide with a potentially wide scope of application especially in organic agriculture, where conventional pesticides are prohibited.

Common bunt of wheat (Tilletia tritici) and stem smut of rye (Urocystis occulta) can cause severe problems in organic production. Field trials have been carried out to study the effects of mustard flour and milk powder on these pathogens. Results showed that seed treatment with mustard flour controlled seed borne infection by T. tritici in wheat without decreasing the germination vigour of the seeds. Full control of T. tritici with milk powder treatments could only be achieved at doses that reduced germination vigour of the seeds. Mustard flour has a potential as a seed treatment in organic agriculture. Both milk powder and mustard flour might be used to control U. occulta in rye.

Common bunt (Tilletia tritici syn. T. caries) is a significant seed borne plant disease in organic agriculture. General measures in ecological crop protection like crop rotation and manuring practice has in practice failed to control this disease, and direct seed treatment therefore seems to be necessary to ensure yield and food quality. Current study indicate that biological control can give successful control without negative effects on seed germination vigour. A combination of biocontrol agents and milk powder improves the effect of the biocontrol. Application of compost to the soil increases the frequency of this disease. The potential role of biocontrol within the principles of ecological disease management is being discussed.

ABSTRACT The disease common bunt (Tilletia tritici syn. caries) has become a more frequent problem in winter wheat in Europe during the last 15 years. In organic farming, common bunt causes serious problems for seed producers, and many seed lots are discarded due to contamination with Tilletia tritici. Owing to the biology of Tilletia tritici, with spores loosely attached to the surface of the grain, there is a risk that spores can be disseminated via grain handling equipment, including combine harvesters. Preventive efforts should focus on the role of grain handling equipment and how the fungus life cycle can be broken. The dissemination of spores via the combiner after harvesting infected fields has been investigated. Six trials were conducted over three years, counting the number of spores in up to seven emptyings of the combiner. Up to four emptyings with non- contaminated grains were needed in order to achieve an acceptably low level of contamination. Using Denmark as a case, several important factors influencing disease spread via harvest equipment are discussed. It is concluded that one easy preventive strategy is to avoid using the first four emptyings of the combiner. This method should always be combined with analysis of seeds for spore load.

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.

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 degreesC. The effect of hot water was enhanced by first soaking the seeds in water at 20 degreesC. Controlling loose smut (Ustilago nuda) is more complicated and here pre treatment with soaking seeds in water at 45 degreesC succeeded by short treatment in water at 50 degreesC gave good results.

Three years of field trials in Denmark have shown that common bunt (Tilletia tritici) is able to infect wheat in crop rotations with several intercrops between susceptible crops. This contradicts most previous literature which concluded that common bunt is a seed-borne pathogen only able to infect through the soil in cases where wheat is grown in two consecutive years. it is argued that the reason for this change in pathogenicity can be explained by a change in farming practice.