Aanpak van zwarte vaten in radijs

In the the year 2007, Dutch radish growers found a new disease symptom in their crop that is called “black veins”. The symptoms are typical dark brown or black veins in the white flesh of the tuber and are also found in leaf stems and roots. These radish plants have reduced growth or will die. Recently in research by Wageningen UR Greenhouse Horticulture, the pathogen appeared to be the bacteria Stenotrophomonas rhizophila. In further experiments the effect of several treatments on the symptoms of black veins has been studied. The varieties Escala, Lennox, Janox, Rossella and Donar showed in this order an increasing susceptibility to the disease. The pathogenic bacteria were found in the soil upto a depth of 70 cm. Especially without steam extraction, steam sterilisation of the soil resulted in too low temperatures and subsequently in insufficient killing of the pathogen. A high dose of feather meal reduced the symptoms very much. However, the dosing is too high for practical use. Soil sterilisation by a high amount of fermented organic material resulted in less symptoms of black veins. Adding Compete Plus to the soil, which mainly is a mixture of several bacteria, was the best in suppressing the infection of all non-chemical materals used in the experiment.