Beet leaf spot is a very common disease that appears every year on plantations. It becomes dangerous after the inter-rows close together due to the persistence of increased humidity in the field. Before the BBCH 39 phase, beet leaves are aerated, which helps to dry their surface, and thus makes it difficult for spores to germinate and for hyphae to penetrate through respiratory slits into the leaf blade pulp.
Initially, symptoms of the disease appear on older leaves, at the turn of June/July (the date depends on many factors, including the region, weather and variety) in the form of small spots surrounded by a red-brown border. These are classic, most easily recognizable symptoms. The center of the spots is initially light, then grayish, which is associated with the production of conidia, which, however, cannot be clearly observed with the naked eye. This is best seen in magnification. As the disease progresses, the spots enlarge, additionally appear on younger leaves, then merge with each other, creating necroses. In the end, the foliage dries up, and its reconstruction takes place at the expense of accumulated sugar, which is why the polarization of severely damaged roots is relatively low. The head takes on a conical shape, and the root stops gaining weight. The technological value of the juice also deteriorates.
