Austrian farmers perception of new weeds.

The composition of weed floras in Central European fields has shifted creating a novel management issue: new weeds, that is, species that are currently spreading and increasing in impact. In their role as primary decision makers on the ground, farmers' perception of these new weeds plays a pivotal role in collecting information on their occurrence and control. We conducted an online survey to determine if Austrian farmers recognized 15 selected new weed taxa (12 species and 3 genera) from their farm. The 181 surveyed farmers also estimated the required management effort for these species and elicited their current management practices. Additional questions were posed to understand farmers' general perception of changes in the weed flora. We used a generalized linear mixed model to estimate differences in management effort and identify new weeds that merit monitoring and management programs. Two weed genera (Fallopia spp. and Panicum spp.) showed significantly higher than average management effort. The most commonly used management measures were manual removal, herbicide use and crop rotation. A majority of farmers reported changes in the weed flora; over two thirds reported new species and over one third reported new weeds that were difficult to control. In summary, our results suggest that respondents were aware of the challenges posed by new weeds but required more information on management and prevention strategies.

Alien Species and Human Health: Austrian Stakeholder Perspective on Challenges and Solutions.

No saturation in the introduction, acceleration of spread and the increasing impacts of alien species are a characteristic feature of the Anthropocene. Concomitantly, alien species affecting human health are supposed to increase, mainly due to increasing global trade and climate change. In this study, we assess challenges and solutions posed by such species to the public health sector in Austria over the next few decades. We did so using an online questionnaire circulated to 131 experts and stakeholders working on human health and biological invasions, supplemented by in-depth interviews with eleven selected experts. Results from the online survey and in-depth interviews largely support and complement each other. Experts and stakeholders suggest that (i) the allergenic Ambrosia artemisiifolia (common ragweed), the photodermatoxic Heracleum mantegazzianum (giant hogweed), and vectors of diseases such as Aedes albopictus (Asian tiger mosquito) are considered the alien species posing the most severe challenges; (ii) challenges are expected to increase in the next few decades and awareness in the public health sector is not sufficient; (iii) effective and efficient solutions are mainly related to prevention. Specific solutions include pathway management of introduction and spread by monitoring and controlling established populations of ragweed, hogweed and mosquitos.

Short- and long-term response of sunflower to airborne bromoxynil-octanoate under controlled and field conditions.

Wind tunnel studies and a field study were conducted to investigate the impact of the airborne herbicide bromoxynil-octanoate on non-target plants. Sunflowers at the two-leaf stage were used as test plants and exposed for 24 h in a wind tunnel to a range of concentrations of airborne bromoxynil-octanoate. Quantum yield of electron transport at Photosystem II (phiPSII) of exposed leaves and leaves developed after exposure, plant height, days to flower and head diameter were used to determine the short- and long-term response of sunflowers to bromoxynil-octanoate. Quantum yield of exposed leaves and of the second leaf pair, determined 1 h and 2 days after exposure, was reduced at concentrations >0.449 and >1.159 microg/m3, respectively, but no effects on further leaf pairs developed after exposure were observed. Growth parameters were partly affected when exposed to >1.448 microg/m3. In a field study a maize plot was treated with bromoxynil-octanoate and parathion-methyl, used as a tracer compound. Afterwards, potted sunflowers were placed inside the maize plot and at different distances (2, 4, 8 and 16 m) from the treated plot. The highest concentrations of bromoxynil-octanoate and parathion-methyl collected in air samples at a distance of 8 m outside of the treated plot were 0.100 and 0.055 microg/m3, respectively. Little of the breakdown product bromoxynil phenol was detected in the air. Detectable concentrations of bromoxynil-octanoate and bromoxynil phenol were found only in a few leaf samples, whereas parathion-methyl was detected in almost 50% of the leaf samples up to 16 m from the treated plot. Quantum yield and growth of sunflower were not affected due to low concentrations of bromoxynil-octanoate in the air.

Effect of airborne bromoxynil-octanoate and metribuzin on non-target plants.

The present study was conducted to determine the effects of airborne herbicides on the photosynthesis and growth of non-target plants. Sunflowers at different growth stages were used as test plants and exposed for 24 h in a wind tunnel to a range of concentrations of bromoxynil-octanoate and metribuzin. The quantum yield (phiPSII) and the dry weight were used as response parameters. Results indicate that young sunflower plants are affected by sublethal concentrations of both herbicides, whereas metribuzin proved to be more phytotoxic. Bromoxynil-octanoate and metribuzin concentrations > 0.265 and >0.135 microg/m(3) impair the photosynthetic activity of exposed leaves and concentrations >0.780 and >0.641 microg/m(3) of leaves developed after exposure. Effects on dry weight indicate that younger plants were more susceptible, whereby the response to metribuzin proved to be more dependent on growth stage. Based on these results and considering herbicide concentrations in ambient air, there is a reasonable probability that non-target plants are temporarily at risk of being affected.