Phytosanitary measures in the European Union: a call for more dynamic risk management allowing more focus on real pest risksCase study: Potato spindle tuber viroid (PSTVd) on ornamental Solanaceae in Europe

After fifteen years of harmonisation of phytosanitary measures in the European Union, today's legislation has become increasingly stagnant, complex and detailed. The recent finding of Potato spindle tuber viroid in ornamental plants in the Netherlands and other Member States illustrates the struggle to take prompt emergency measures when specific knowledge is not available. It is proposed that the European Commission should take the initiative to organise the process of pest risk analysis from beginning to end. In addition, the Commission should have budgets at their disposal for instantaneous research to generate the required data and fill in knowledge gaps. Such policy enables evaluation of emergency measures and implementation of permanent requirements on the basis of scientific data within a short period, thereby creating a dynamic legislation that focuses on real pest risks.     

Identification and characterization of Pepino mosaic potexvirus in tomato

At the beginning of 1999, a new virus disease occurred in protected tomato crops in The Netherlands. Initial diagnostic tests revealed the presence of a potexvirus but serological tests ruled out the presence of Potato X potexvirus (PVX). Tests for other potexviruses reported from solanaceous crops provisionally identified the virus as Pepino mosaic potexvirus (PepMV). The virus was purified, and an antiserum was produced, which showed strong reactions with both the type isolate of PepMV from pepino and two other isolates from tomato. Host range and symptomatology of the pepino and tomato isolates of PepMV revealed clear differences from PVX. However, differences were also observed between the pepino and tomato isolates of PepMV. Sequence alignment of DNA fragments of 584 bp derived from the RNA polymerase cistron showed almost 95% identity with the pepino isolate, whereas the identity with PVX appeared to be < 60%. Together, these results identified PepMV as the causal agent of the new virus disease in tomato. Based on the differences from the type isolate from pepino ( Solanum muricatum ), the isolates from tomato should be considered as a distinct strain of PepMV for which the name tomato strain is proposed.     

Early harvest and ensilage of forage sorghum infected with ergot (Claviceps africana) reduces the risk of livestock poisoning

Sorghum ergot produces dihydroergosine (DHES) and related alkaloids, which cause hyperthermia in cattle. Proportions of infected panicles (grain heads), leaves and stems were determined in two forage sorghum crops extensively infected 2 to 4 weeks prior to sampling and the panicles were assayed for DHES. Composite samples from each crop, plus a third grain variety crop, were coarsely chopped and half of each sealed in plastic buckets for 6 weeks to simulate ensilation. The worst-infected panicles contained up to 55 mg DHES/kg, but dilution reduced average concentrations of DHES in crops to approximately 1 mg/kg, a relatively safe level for cattle. Ensilation significantly (P = 0.043) reduced mean DHES concentrations from 0.85 to 0.46 mg/kg.     

The effects of different anesthetics on blood steroid concentrations in domestic tom-cats

Testosterone and androstenedione were measured in the plasma of mature tom-cats before, during and after anesthesia with thiopentone, ketamine, xylazine and alphaxolone/alphadolone. Samples were collected via an indwelling jugular catheter at 30 min intervals before anesthesia (5 samples) and during the recovery phase (8 samples), and at intervals of 15 min during anesthesia (7 samples). Thiopentone and ketamine anesthesia significantly depressed testosterone and androstenedione concentrations during and after anesthesia. Xylazine significantly increased testosterone concentrations during anesthesia but they returned to pre-anesthetic concentrations during recovery. Androstenedione concentrations were significantly depressed during the recovery phase from xylazine anesthesia. Alphaxolone/alphadolone anesthesia had no significant effect of testosterone concentrations but significantly increased and androstenedione concentrations during anesthesia and recovery. Testosterone and androstenedione concentrations in cats were significantly altered by these 4 commonly used anesthetics and this must be taken into account if hormone concentrations are measured while cats are anesthetised.     

First report of Colombian datura potyvirus in tomato

Colombian datura potyvirus (CDV) was detected in about 300 plants of tomato Cabrion in one greenhouse in the Netherlands. Virus identification was based on host range and symptomatology, aphid transmission, electron microscopy and serology. Evidence was obtained that the tomato plants were infected by viruliferousMyzus persicae that acquired the virus from a CDV-infectedBrugmansia plant present in the same greenhouse.     

The structure of the upper atmosphere of mars: In situ accelerometer measurements from mars global surveyor

The Mars Global Surveyor (MGS) z-axis accelerometer has obtained over 200 vertical structures of thermospheric density, temperature, and pressure, ranging from 110 to 170 kilometers, compared to only three previous such vertical structures. In November 1997, a regional dust storm in the Southern Hemisphere triggered an unexpectedly large thermospheric response at mid-northern latitudes, increasing the altitude of thermospheric pressure surfaces there by as much as 8 kilometers and indicating a strong global thermospheric response to a regional dust storm. Throughout the MGS mission, thermospheric density bulges have been detected on opposite sides of the planet near 90 degreesE and 90 degreesW, in the vicinity of maximum terrain heights. This wave 2 pattern may be caused by topographically-forced planetary waves propagating up from the lower atmosphere.