Organic farming in isolated landscapes does not benefit flower-visiting insects and pollination

Organic farming has often been found to provide benefits for biodiversity, but the benefits can depend on the species considered and characteristics of the surrounding landscape. In an intensively farmed area of Northeast Italy we investigated whether isolated organic farms, in a conventionally farmed landscape, provided local benefits for insect pollinators and pollination services. We quantified the relative effects of local management (i.e. the farm system), landscape management (proportion of surrounding uncultivated land) and interactions between them. We compared six organic and six conventional vine fields. The proportion of surrounding uncultivated land was calculated for each site at radii of 200, 500, 1000 and 2000 m. The organic fields did not differ from the conventional in their floral resources or proportion of surrounding uncultivated land. Data were collected on pollinator abundance and species richness, visitation rates to, and pollination of experimental potted plants. None of these factors were significantly affected by the farming system. The abundance of visits to the potted plants in the conventional fields tended to be negatively affected by the proportion of surrounding uncultivated land. The proportion fruit set, weight of seeds per plant and seed weight in conventional and organic fields were all negatively affected by the proportion of surrounding uncultivated land. In vine fields the impact of the surrounding landscape was stronger than the local management. Enhancement of biodiversity through organic farming should not be assumed to be ubiquitous, as potential benefits may be offset by the crop type, organic-management practices and the specific habitat requirements in the surrounding landscape.     

An AM fungus and a PGPR intensify the adverse effects of salinity on the stability of rhizosphere soil aggregates of Lactuca sativa

A mesocosm experiment was conducted to examine the effect of an arbuscular mycorrhizal (AM) fungus (Glomus mosseae (Nicol & Gerd.) Gerd. & Trappe) and a plant growth-promoting rhizobacterium (PGPR) (Pseudomonas mendocina Palleroni), alone or in combination, on the structural stability of the rhizosphere soil of Lactuca sativa L. grown under two levels of salinity. The plants inoculated with P. mendocina had significantly greater shoot biomass than the control plants at both salinity levels, whereas the mycorrhizal inoculation was only effective in increasing shoot biomass at the moderate salinity level. The aggregate stability of soils inoculated with the PGPR and/or G. mosseae significantly decreased with increasing saline stress (about 29% lower than those of soils under non-saline conditions). Only the inoculated soils showed higher concentrations of sodium (Na) under severe saline stress. The severe salinity stress decreased the glomalin-related soil protein (GRSP) concentration, but the highest values of GRSP were recorded in the inoculated soils. Our findings suggest that the use of AM fungi and/or a PGPR for alleviating salinity stress in lettuce plants could be limited by their detrimental effect on soil structural stability.     

BHV-1 eradication program in Bavaria: a marker-independent strategy

In Bavaria a BHV-1 eradication program was initiated in 1986 and was changed to a compulsory program in 1998. The eradication success increased progressively from < 50% in 1986 to 87% of the farms in 2002. BHV 1-free farms are controlled by bulk milk serology twice a year along with blood serology in animals that are negative but from herds where positive field virus infected animals are present. All serological tests are performed with an indirect ELISA test, all positive results are confirmed by a gB ELISA. Currently about 100.000 virus infected cattle are in Bavarian herds, approximately 80% of these animals are in heavily infected herds (> 10 infected animals). These herds comprise about 5% of all Bavarian herds. The eradication of the virus in these heavily infected herds is the most diifficult, whereas the prevention of new infections appears controllable. In this review current problems in BHV1 eradication are named and possible improvements are discussed.     

Seroepidemiological studies of zoonotic infections in hunters in southeastern Austria--prevalences,risk factors,and preventive methods

The aim of this study was to investigate the seroprevalences to zoonotic pathogens in hunters, to propose preventive measures and to obtain more information about the occurrence of zoonotic pathogens in local wild animal populations. From 146 male and 3 female hunters originating from the south-eastern Austrian federal states of Styria and Burgenland blood samples were taken and anamnestic data were obtained using a questionnaire. The serological investigations included the following viral, bacterial and parasitic zoonotic agents or zoonoses, respectively (antibody-seroprevalences in brackets): encephalomyocarditis virus (EMCV, 15%), Puumala-Hantavirus (10%), Newcastle Disease virus (NDV, 4%), borreliosis (IgG 42%, IgM 7%), brucellosis (1%), chlamydiosis (3%), ehrlichiosis (IgG 15%, IgM 3%), leptospirosis (10%), tularaemia (3%), Q fever (0%), Echinococcus multilocularis/E. granulosus (5%/11%), toxocariasis (17%). Out of a control group of 50 persons (urban population, no hunters) only one person was found to be seropositive for Toxocara canis and NDV and four for EMCV, all other results were negative in the control group. The high seroprevalences especially to Borrelia burgdorferi s.l., Ehrlichia spp., Leptospira interrogans, E. granulosus, E. multilocularis, encephalomyocarditis virus and Puumala virus demonstrate that hunters are particularly exposed to zoonotic pathogens. It should also be noted that one hunter was seropositive for Brucella abortus and five exhibited antibodies to Francisella tularensis. In these cases, as well as in the cases of the 15 seropositives for Leptospira interrogans, the suspected source of infection may--besides rodents--also include wild boars and brown hares. The infections with NDV and Chlamydophila psittaci may be traced back to contact with certain species of birds (potential risk: aviaries). For Hantaviruses, rodents are considered to be the main source of human infections.     

The carbamoylation and spontaneous reactivation of the cabbage carboxylesterase after interaction with carbofuran

The interaction of carbofuran with carbage carboxylesterase was studied. The kinetic constants of carbamoylation and spontaneous reactivation were determined. The carbamoylation of cabbage carboxylesterase probably proceeds in a way similar to that of insect and/or animal acetylcholinesterase.     

Nitrate deficiency reduces cadmium and nickel accumulation in chamomile plants

The effect of nitrogen (nitrate) deficiency (-N) on the accumulation of cadmium (Cd) and nickel (Ni) in chamomile ( Matricaria chamomilla ) plants was studied. Elimination of N from the culture medium led to decreases in N-based compounds (free amino acids and soluble proteins) and increases in C-based compounds (reducing sugars, soluble phenols, coumarins, phenolic acids, and partially flavonoids and lignin), being considerably affected by the metal presence. Proline, a known stress-protective amino acid, decreased in all -N variants. The activity of phenylalanine ammonia-lyase was stimulated only in -N control plants, whereas the activities of polyphenol oxidase and guaiacol peroxidase were never reduced in -N variants in comparison with respective +N counterparts. Among detected phenolic acids, chlorogenic acid strongly accumulated in all N-deficient variants in the free fraction and caffeic acid in the cell wall-bound fraction. Mineral nutrients were rather affected by a given metal than by N deficiency. Shoot and total root Cd and Ni amounts decreased in -N variants. On the contrary, ammonium-fed plants exposed to N deficiency did not show similar changes in Cd and Ni contents. The present findings are discussed with respect to the role of phenols and mineral nutrition in metal uptake.     

A comparison of the effect of tiamulin hydrogen fumarate and tylosin tartrate on mycoplasmas of ruminants and some animal ureaplasmas

The in vitro efficacy of tiamulin was compared to that of tylosin against 7 bovine, 7 ovine and 3 caprine mycoplasma strains isolated from various organs and belonging to different species, as well as 7 ureaplasma strains cultured from cattle, sheep, swine, chickens and turkeys. The minimal mycoplasmacidal concentrations of tiamulin varied between 0.01 and 10.0 μg ml^?1, while tylosin proved to be active in concentrations of 0.5 and 100.0 μg ml^?1. Five of mycoplasma strains showed identical sensitivities to both antibiotics while all other strains, including the ureaplasmas, were sensitive to tiamulin at concentrations 5–5000-times lower than tylosin.