Pythium oligandrum Drechs. belongs to the order Oomycetes. It is parasitic on many fungi from the same or other orders. The antagonism of P. oligandrum is a multifaceted process dependent on the target species involved. P. oligandrum is nonpathogenic on 12 species of crops from six families. It does not attack their tissue but occurs on the root surface, predominantly in the regions of hypocotyl -taproot, together with plant pathogenic fungi. It utilises the root exudates and fungus hyphae on the root surface, including those of the plant pathogens, for its own support. A growth stimulation of plants was observed. P. oligandrum can be utilised for biological control on a wide spectrum of crop plants. Different methods of application have been developed. The effect of a mycoparasite preparation is more preventive.
Trichoderma harzianum is a worldwide soilborne anamorphic fungus. It is a facultative parasite of a wide spectrum of fungi, but can also live as a saprophyte. The manifestation of its antagonism displays as support competition, parasitism and antibiosis. Some species of the genus Trichoderma can be utilised in plant protection because of their mycoparasitic and other properties. The biofungicide Supresivit containing conidia of T. harzianum is registered in the Czech Republic. A commercially prepared mixture of the biopreparation and granulated mineral fertiliser is a novel way to introduce it into the plant environment. To make optimal use of biological control methods it is necessary to integrate them in a complete system for the control of plant diseases. It is quite possible to combine two or more biological control agents, but these could also be used together with certain chemicals to improve disease control.
During the years 2013-2015, the occurrence of fungi causing postharvest diseases of apples was evaluated in three apple orchards with integrated and organic production systems in the Czech Republic. The postharvest disease fungi were more frequently recorded in fruits from organically cultivated apple trees (average 29.97%) than those from integrated production (17.67%). This difference is statistically significant. Neofabraea, Penicillium, Alternaria and a sterile grey mycelium were the most frequently recorded taxa in apples grown in organic and integrated production systems. There were also significant differences in the frequency of occurrence of the most frequent fungal taxa between years. In 2013 and 2014, Neofabraea was the most frequently isolated genus in both cultivation systems, whereas in 2015, Penicillium was the most frequently recorded genus also in both cultivation systems, which was likely caused by the low precipitation in the 2015 growing season.
The influence of fungicides on the production of the trichothecene mycotoxin deoxynivalenol (DON) has been fairly intensively studied. MAGAN et al. (2002) examined the in vitro efficacy of fungicides to control Fusarium species in cereals and the effect in the field on both Fusarium infection of ripening ears and mycotoxin production. The field studies suggested that fungicides such as tebuconazole and metconazole provide good control of both Fusarium infection of ears and DON production.Azoxystrobin and related fungicides were less effective and grain from treated crops sometimes had an increased concentration of nivalenol and deoxynivalenol. Studies with F. culmorum isolates from different parts of Europe showed a complexity of interactions occurring between environmental factors, the type of fungicide and isolate in relation to growth inhibition and DON production. These studies confirmed the ineffectiveness of azoxystrobin and suggested that environmental stress Eight varieties of spring barley (Hordeum vulgaris Lin.) were artificially inoculated with a Fusarium culmorum (W.G. Smith) Saccardo -isolate and naturally infected in the middle of the flowering period, and 2 d later treated with the fungicides azoxystrobin or tebuconazol at a dose of 1 l/ha in 250 l of water. In both control and treated samples of grain the content of deoxynivalenol (DON), the main trichothecene mycotoxin produced by F. culmorum, was determined by gas chromatography (GC-ECD). The treatment with either fungicide resulted in elevated levels of DON, an effect that was more pronounced with azoxystrobin.
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