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Allelopathic effect of invasive plants (Eriochloa villosa, Asclepias syriaca, Fallopia x bohemica, Solidago gigantea) on seed germination
179-182Views:257The aim of this study was to determine the allelopathic potential of invasive species woolly cupgrass (Eriochloa villosa), common milkweed (Asclepias syriaca), bohemian knotweed (Fallopia x bohemica), and giant goldenrod (Solidago gigantea Ait.) on germination crop (Lepidium sativum L.). Experiments were conducted under laboratory conditions to determine effect of water extracts in petri dish bioassay. Water extracts from fresh biomass (leaves and stem) of invasive weeds in concentrations of 4 and 8 g/100 ml were investigated. All invasive plants showed allelopathic effect on germination. In giant goldenrod stem water extract experiment, allelopathic effect was less pronounced.
The cress germination was greatly suppressed with the woolly cupgrass, common milkweed and the giant goldenrod. The experiment showed that the seed germination depended on the concentrations and the plant material used (leaves and stem).
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Characterization of two rust fungi related to biological control concept in Hungary
195-199Views:274Weeds cause serious problems in agriculture on a global scale. These plants reduce yield and the quality of crops by competing for water, nutrients and sunlight. The improper or excessive usage of herbicides have led to development of resistance in some weed species while contaminating the environment; therefore, biological control has an increasing role as an alternative method for controlling special weed species.
The aim of this study is to make a brief review of biological control of weeds by pathogens and to characterize two rust fungi (Puccinia lagenophorae and Puccinia xanthii) which are broadly examined recently in a biological control concept and have been found on their hosts, such as common groundsel (Senecio vulgaris L.) and common cocklebur (Xanthium strumarium L.), two common and difficult to manage weeds both in horticultural and agricultural lands also in Hungary.
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Preliminary estimation of the efficacy of Fusarium sporotrichioides Sherb. as biological control agent against common milkweed (Asclepias syriaca L.)
201-204Views:248A 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.
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Fusarium culmorum isolated from rhizosphere of wooly cupgrass (Eriochloa villosa) in Debrecen (East Hungary)
93-96Views:143Wooly cupgrass (Eriochloa villosa) is an East-Asian originated weed species and it has been spreaded worldwide by now. The first occurrence of this species in Hungary was observed and published in 2008 nearby Gesztely village (Borsod-Abaúj-Zemplén county, North-East Hungary) than in the summer of 2011 a significant population was discovered next to Debrecen city (Hajdú-Bihar county, East Hungary).
In 2013 this weed was also reported from Szentborbás village, Somogy county (South-West Hungary). These observations of spreading and its biological features (production of stolons and large number of seeds, moreover herbicide tolerance) indicate that wooly cupgrass (E. villosa) has a great potential of invasiveness, so it may become a hazardous weed not only in Hungary but in all over the world.
The objective of this study was to identify the fungus which was isolated from wooly cupgrass (E. villosa) root residue samples which were collected after maize harvesting on arable land in late autumn, near Debrecen. The identification of the fungus based on morphological characters of colonies and the features of conidia developed on potato dextrose agar (PDA) plates. After the examination of axenic culture we revealed that the fungus from rhizosphere of wooly cupgrass was Fusarium culmorum. Pathogenicity and/or endophytic relationship between the fungus and wooly cupgrass is still uncertain so pathogenicity tests and reisolations from plants are in progress.
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New occurence of woolly cupgrass (Eriochloa villosa [Thunb.] Kunth) in Hajdúság area, East-Hungary
51-54Views:212Because of the globalization and global warming the emergence of invasive weeds in Hungary are more common. The woolly cupgrass (Eriochloa villosa [Thunb.] Kunth) is published as an important invasive weed in Hungary. Woolly cupgrass is native in East Asia and it spreads into several parts of the World and causes difficulties in plant protection. It has been spreading extensively during the last few years,as the weed shows a very serious invasion potential.
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Woolly cupgrass (Eriochloa villosa /Thunb./ Kunth), a recently occured invasive weed in Trans-Tisza Region and a trial for control in maize
53-57Views:242To the effective control of invasive weeds are essential to prevent establish, if has already happened obstacle to massive accumulation, and promoting the efficient and rapid eradication, if it is possible. The Woolly cupgrass (Eriochloa villosa /Thunb./ Kunth) belongs to weeds which “hard to control” especially in corn. One of the difficulties of effective control is the prolonged emergence causing avoidance of several individuals the contact with pre-emergent herbicides. Another problem arises due to the intensive use of post-emergence herbicide products with short duration of action. To optimalize of timing of treatment is essential for successful control of later emerging weeds. The recently established Woolly cupgrass in Hungary shows resistance or reduced susceptibility to substantial portion of herbicides used in corn. The data collected from small-plot trials demonstrates that application of sulfonylurea or selective monoctyledonous herbicides can be effective against the Woolly cupgrass.
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Mass occurrence of a Phoma-like fungus on common ragweed (Ambrosia artemisiifolia) in Hajdúság region, East Hungary
55-60Views:207Common ragweed (Ambrosia artemisiifolia L.) is one of the most important, allergenic weed species in Hungary. A. artemisiifolia invades both a broad range of often disturbed areas (brownfields) and either undisturbed ones like waste lands, roadsides, riverbanks and railway tracks. In field crops it can cause considerable yield losses mainly in sunflower, maize, cereals and soybean. In Hungary many inhabitants suffer from allergy caused by Ambrosia pollen which results a serious human-health risk. The aim of the control is to prevent flowering and seed propagation of A. artemisiifolia. Until now the occurrence of numerous pathogenic fungi which attack common ragweed plants have been identified in Hungary, however there is not yet available biological weed control program because of shortage in acceptable effectiveness, and endangering cultural plant species. During our weed surveys in the region of Hajdúság (East-Hungary) we found numerous common ragweed plants showing heavy necrotic lesions on leaves and stems. The objective of this study was to identify the fungus which was isolated from diseased tissues of common ragweed (A. artemisiifolia). The identification of fungus based on morphological characters of colonies and features of conidia and chlamydospores developed on malt extract agar (MEA) plates. After examination of axenic cultures we revealed that the fungus isolated from the leaves ands stems of common ragweed was a Phoma-like species.
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Allelopathic effects of water extracts of pieces of wooly cupgrass (Eriochloa villosa) on the seedlings of field crops
167-170Views:153In Hungary, the woolly cupgrass (Eriochloa villosa [Thunb.] Kunth) endanger row crops (i.e. corn, sunflower). Its fast spreading based on some reason viz. long-lasting emergence, reduced sensitivity to many kinds of herbicides, vigorous competitional ability and fast initial growth. Allelopathy, ability of many plant species to produce one or more biochemicals wgich is used tocompete with each others. In this experiment we examined, whether the woolly cupgrass possesses allelopathy, and if so, how influences on the development of cultured crops like maize, sunflower and lettuce.