6. Common diseases of snap bean (Phaseolus vulgaris L.) for biological production

Author: Olga Georgieva, Natalia Karadzhova

DOI: 10.22620/agrisci.2021.29.006

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The main diseases of snap bean (Phaseolus vulgaris L.) for organic production and the possibilities for control have been studied. The strategic directions of the experimental work included: monitoring of diseases; study of pathogens’ variability; the field resistance of the Bulgarian bean varieties “Evros” and “Tangra” to the diseases in organic farming; optimization of the phytosanitary state of the crop through the authorized plant protection products. It has been established that seed-borne diseases are of predominant importance for organically grown garden beans. These are bacterial blight Xantomonas axanopodis pv. phaseoli, halo blight Pseudomonas syringae pv. phaseolicola and anthracnose Colletotrichum lindemuthianum. The screening of Bulgarian bean varieties for disease resistance showed that the “Evros” variety is relatively resistant to bacterial blight and anthracnose, which makes it suitable for growing by biological technologies. The development of bacterial blight and anthracnose after five treatments with the fungicide Bordeaux Mix 20VP (Bordeaux mixture 200 g/kg Cu +) with an interval of 10-14 days, starting from the flowering phase, is in the range up to 12.5%.