Kunstmatige besmetting van haver met stuifbrand,Ustilago avenae (Pers.) Jens

Summary

Seeds of oats contaminated with loose smut were used for testing the fungicidal value of cereal seed disinfectants. As it was impossible to obtain contaminated seed from the field in recent years several methods for artificial contamination were tried.

The best result (14% of smutted panicles), was obtained with the „wet vacuum” method ofHaarring. With the aid of a dessiccator and a water jet pump the air between the glumes and kernels was replaced, by a spore suspension. The degree of infection was the same when the nutrient solution was replaced by tap water.

The method used byPonchet gave 10% of diseased panicles. Here the seed is merely submerged in a spore suspension or is presoaked in tap water and mixed afterwards with dry spores. To obtain contaminated seeds of oats for the testing of seed disinfectants this method is preferable, because of its easy application and the satisfactory degree of infection obtained.

Some other methods of mixing seed and spores without the addition of water gave only 1% of smutted panicles. The highest degree of diseased plants was obtained when the seed was dried directly after the artificial contamination.