Kiegészítések az Orobanche reticulata biológiájához és hazai elterjedéséhez

A közlemény az Orobanche reticulata néhány új magyarországi adatáról számol be. A fajt a szakirodalomban ismeretlen gazdanövényről, Carduus hamulosus-ról gyűjtöttük a Keleti-Bakonyban, a Bér-hegyen. A Magyarországon általában májustól júliusig virágzó faj életmenetéhez érdekes adalék egy extrém csapadékos év (2010) enyhe őszén megfigyelt késői, októberi virágzása is. Egy másik populáció (Vértes hegység, Magyaralmás) érdekessége annak tömegessége. Itt az O. reticulata 2020 nyarán egy, az előző évben beszántásra került természetes szárazgyep élőhely parlag­ján jelent meg nagy tömegben (több száz egyed), Carduus nutans subsp. leiophyllus és Carduus acanthoides gazdanövényen. A fajt néhány olyan flóratérképezési kvadrátból is közöljük a Dunántúli-középhegység, Külső-Somogy és Mezőföld területéről, ahol eddig nem volt ismert.

Spill-over attack by the gall fly, Urophora stylata, on congeners of its target weed, Cirsium vulgare

The gall fly, Urophora stylata, was released in New Zealand in 1998 as a biocontrol agent for the thistle weed, Cirsium vulgare (Scotch thistle). In the summer of 2018, a survey was conducted to assess the field host range of the biocontrol agent in New Zealand. A random selection of 18 pasture populations under sheep and/or beef production, where C. vulgare was present, was surveyed to quantify the attack intensity (gall size relative to seedhead size) on C. vulgare, and the presence of attack on other thistle weeds within the same population. At each location, seedheads were collected from C. vulgare and all other thistle species (Cardueae) present, which included Cirsium arvense (Californian thistle), Cirsium palustre (marsh thistle), Carduus nutans (nodding thistle), and an Arctium species (burdock). In addition to attack on C. vulgare, the gall fly was recorded on C. arvense (at six locations) and C. palustre (at one location). The probability of the presence of attack on C. arvense was positively correlated with the attack intensity on C. vulgare, suggesting that attack on C. arvense is a ‘spill-over effect’ occurring where seedheads of C. vulgare are in limited supply.

Working smarter, not harder: objective-dependent management of an invasive thistle, Carduus nutans

Many invasive species managers state that their objective is to “control” an invader. However, the appropriate choice of a management option requires a more explicit statement of management objectives, in terms of both the relevant time horizon and spatial scale. Using data from a 2-yr mowing experiment, we show that the most effective management strategy for controlling an invasive thistle depends fundamentally on the management goals. We integrate field data from a two-cohort experiment with modeling to assess 14 mowing treatments (differing in intensity, frequency, and timing, and thus also in their required logistical effort) based on their effectiveness in (1) reducing population density of the existing cohort, (2) decreasing projected long-term population growth, and (3) limiting projected population spread of an invasive thistle, musk thistle (Carduus nutans L.). The treatment with high intensity and a single late mow caused the largest reduction in plant survival (and density of existing adult plants); the treatment with high intensity and an early mow in addition to a late mow was most effective at reducing population growth rate and population spread. Against expectation and conventional wisdom, the most frequent mowing treatment did not provide the most effective management outcome for any stated objective. This study highlights the necessity of clearly defined management aims; the term “control” is too vague to be truly useful. The results also provide important insights for the management of this invasive species.

Nickende Distel – Blume des Jahres 2008

Die Nickende Distel (Carduus nutans) ist Blume des Jahres 2008. Ihr äußeres Erscheinungsbild, ihre Biologie und Ökologie werden vorgestellt. Unterschiede zu anderen Disteln werden erwähnt.

Carduus nutans L and the Effect on the Heavy Metals and Microenvironment Biota

The aim of the study was to identify the effect of Carduus nutans L on the heavy metals and microenvironment biota. Ten plants of Carduus nutans L were collected togheter with the rhizosphere soil and as reference the soil was collectued from an abandonated pasture where no vegetation was growing. The metal concentrations in the filtrate were determined by flame atomic absorption spectrophotometry and the total number of bacteria and actinomycetes from the average soil samples was established. Based on the mathematical models we managed to identify the effects of the heavy metals present in the Carduus nutans L rhizosphere soil samples on the development and presence of bacteria and actinomycetes colonies. We can state that iron and manganese influence the CFU of bacteria and actinomycetes and these in their turn have an impact on the zinc concentration in soil which will influence total chromium content and copper concentrations.