In a series of laboratory experiments, acclimated pupae of Tuta absoluta were exposed to various constant low temperatures in order to estimate their maximum survival times (Kaplan–Meier, Lt99.99). A Weibull function was fitted to the data points, describing maximum survival time as a function of temperature. In another experiment at −6°C, the progress of mortality increasing with exposure time was identified. These values were fitted by a sigmoidal function converging asymptotically to 100% mortality for very long exposure times. Analysing mortality data from the maximum survival experiment by a generalized linear model showed a significant common slope parameter (p < .001) that reveals parallelism of the survival curves at each temperature if a log time axis is used. These curves appear stretched (time scaled) if plotted with a nonlogarithmic time axis. By combining these mathematical relations, it was possible to calculate a species‐specific ‘mortality surface’ which exhibits mortalities, depending on temperature and duration of exposure. In order to accumulate hourly mortalities for courses of varying temperatures, an algorithm was developed which yields mortality values from that surface taking into account the attained mortality level. In validation experiments, recorded mortalities were compared against modelled mortalities. Prediction of mortality was partially supported by the model, but pupae experiencing intensely fluctuating temperatures showed decreased mortality, probably caused by rapid cold hardening during exposure. Despite this observation, mortality data converged to distinct levels very close to 100% depending on the intensity of temperature fluctuations that were characteristic for different types of experiments. The highest mortality limit occurred at intensely fluctuating temperatures in laboratory experiments. This constituted a benchmark that was not reached under various field conditions. Thus, it was possible to identify temperature limits for the extinction of field populations of Tuta absoluta pupae.

Experiments were carried out to investigate whether Potato spindle tuber viroid (PSTVd) can be transmitted intra-and inter-species from infected Solanum jasminoides to non-infected S. jasminoides and S. esculentum and from infected Brugmansia sp. to S. esculentum by Frankliniella occidentalis and Thrips tabaci by leaf sucking. The F. occidentalis experiments also included feeding on pollen prior to feeding on PSTVd-infected leaf. No thrips-mediated transmission of PSTVd was recorded. The possibility of PSTVd transmission by Apis mellifera and Bombus terrestris during their feeding/pollinating activities within ornamentals and from ornamentals to S. esculentum was included, and no bee-mediated transmission was recorded.

Hatching of the larvae of Elodia morio (Tachinidae, Diptera) from their microtypical eggs in the gut of their host and under artificial conditions Attempts to induce hatching of Elodia morio eggs by simulation of conditions in the gut of their host‐larvae Laspeyresia pomonella (L.) (Lepidoptera) were successful. Two conditions were necessary: protease caused softening of the egg‐shell and lack of oxygen induced larval movements promoting hatching. Hatching speed depended on the duration of enzyme activity and thus on the degree of egg‐shell softening. Both factors (Oxygen deficiency and presence of protease) were demonstrated for digestive fluids of Laspeyresia pomonella. Zusammenfassung Es gelang, die Larven in den Eiern durch Simulation der Verhältnisse im Darm der Wirtsraupen zum Schlüpfen zu bringen. Dafür waren zwei Faktoren notwendig: Durch Sauerstoffmangel wurden die Larven zu Ausbohrbewegungen veranlaßt. Für ein erfolgreiches Schlüpfen war es jedoch noch erforderlich, daß die Eihülle durch Protease soweit verändert wurde, daß sie für die Larven zu durchdringen war. Die Schlüpfgeschwindigkeit hing dabei davon ab, wie stark die Eihülle durch das Ferment angegriffen worden war. Die vorerst nur vermuteten Faktoren Sauerstoffmangel und Protease konnten im Wirtsdarm nachgewiesen werden.

AAR14 30 km flussaufwärts. Für Bachforelle und Äsche werden geeignete Lebensräume geringer (hohe Übereinstimmung, starke Beweislage). Auch Nutztiere leiden unter dem Klimawandel Zunehmende Hitzeperioden können bei Nutztieren die Leistung verringern, das Krankheitsrisiko erhöhen und bis zum Hitzetod führen (hohe Übereinstimmung, starke Beweislage).

No abstract