STEM ROT ON WILD PEPPERMINT SPECIES ON SOUTH-WESTERN PART OF ROMANIA.

During the diseases surveil conducted on the medicinal plants from south western part of Romania, on the Nera river canyon there are some significant populations of wild peppermint. The idea of the disease surveillance in medicinal plants came from the necessity to determine the pathogens in wild flora as potential threat to the crops and also because it is well known as general principal that the plant of the species from the wild flora are more resistant to pathogens than their relatives from the crop plants because on the breeding process the crop plants lose a lot of diseases resistance genes. From this point of view, if a pathogen is present on plants from the wild flora than it could be expected to be at least present on the crop plants. Also the area where the observations were performed is proper for growing medicinal herbs as intensive crops. At the time when this surveillance take place it was well known that the area is populated with four different species of wild peppermint (Mentha longifolia, M. aquatica, M. arvensis and M. verticilliata). One of the affections found on some of the wild peppermint plants consists on necrotic lesions on the stem. Also, the leaves placed over the lesions shown a start of necrosis which has a progress to the complete leaf necrosis. Populations were noted and since the first encounter was noted this populations was taken under a careful surveillance of the disorder evolution. Observations performed in laboratory show clear picnidia formed on the stem lesions and all data point to Phoma strasseri as pathogen which cause the stem necrosis. Peppermint populations on which we perform the measurements of pathogen virulence and aggressively has as common point that they are situated in the vicinity of Nera stream, but on higher ground and on meadow sandy soil. Plant density on these populations was between 6 and 41 so the results are relevant for the situation. [ABSTRACT FROM AUTHOR]