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Usability of vegetable extracts in the protection against Alternaria alternata
113-116Views:149In our country, wormwood ragweed (Ambrosia artemisiifolia) may cause serious problems. Nearly 5 million hectares of agricultural area was infected with ragweed (Ambrosia artemisiifolia), which is believed useless weed. Allergological point of view, most problematic weeds adventive. However, many physiologically very beneficial compound also included, those with the effects have been known also by the Indians. On this basis, herbs can be thought of as ragweed. Our goal was to present that the ragweed contains antifungal active substances as well. In this paper we tested the biological activity of the extracts against Alternaria alternata F.00750 in vitro. We related based on our examination that ragweed contains biologically active agents, by which it is hampered the reproduction of the Alternaria alternata. The minimum effective concentration was 300 mg extract in a Petri dish, which was three days inhibited the growth of fungus. Full fungicidal effect was observed over dose 525 mg.
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A dual infection of two microscopic fungi on common milkweed (Asclepias syriaca) in Hajdúság region (East-Hungary)
189-195Views:195Common milkweed (Asclepias syriaca L.) is one of the most noxious and invasive weed species in Hungary. A. syriaca invades arable lands, horticultural and forestry plantations, natural and semi-natural habitats too. In cases of field crops it can cause considerable yield losses mostly in maize (2–10%), soybean (12–32%) and sorghum (4–29%), but only with high rate of coverage. It can also increase these problems that the common milkweed can be serve as reservoir and host for viruses, other pathogens and pests.
Because of the importance of common milkweed and in spite of demand to develop effective biological control, until now has not been developed a proper control program against A. syriaca. The aim of our research was to identify the necrotrophic fungal pathogens, which were involved in notable disease occurrence on this weed in different parts of Hajdúság region of Eastern-Hungary in 2016.
To the isolation of fungi from leaves and their identification were based on morphological colony characters on potato dextrose agar (PDA) and Sabouraud dextrose agar (SDA). To the description of conidia features were used PDA for Alternaria and synthetic low-nutrient agar (SNA) for Fusarium species, respectively. The examination of axenic cultures revealed that the fungi isolated from the leaves of common milkweed were Fusarium sporotrichioides and Alternaria alternata. -
Preliminary estimation of the efficacy of Fusarium sporotrichioides Sherb. as biological control agent against common milkweed (Asclepias syriaca L.)
201-204Views:308A study of fungi responsible for severe leaf spots of common milkweed (Asclepias syriaca L.) in the Hajdúság region (East Hungary), Fusarium sporotrichioides and Alternaria alternata were isolated from infested leaf tissues. F. sporotrichioides was the most virulent fungus in pathogenicity tests conducted on healthy leaves of common milkweed plants. Inoculation of common milkweed (A. syriaca) in different growth stages with F. sporotrichioides yielded similar symptoms as the original ones. Spray mixtures containing 1.0×106 conidia/ml gave effective control when common milkweed plants were sprayed until runoff occurred. Laboratory (wet chamber) and field experiments showed that asexual spores of the fungal pathogen, F. sporotrichioides, exhibited bioherbicidal activity against common milkweed (A. syriaca).
More efficient control efficacy was observable on elder plants (at flowering stage) than younger ones. These results initiate that this fungus may be a biocontrol agent for controlling this invasive weed but should clarify its hosts because it could infect cultivated plants as well.