Precision farming and environmental pesticide regulation in the EU-How does it fit together?

Precision farming technology allows pesticides to be applied precisely to the target while leaving the rest of the field untreated. In the regulation of pesticides, however, a homogeneously sprayed field is considered as the standard scenario. To this end, the current status of pesticide risk assessment from the perspective of terrestrial vertebrates, terrestrial invertebrates, and plants as well as aquatic organisms was examined with respect to the EU registration of a pesticide to be applied via precision farming techniques. We highlight which and how respective parts of the technical procedures could be adapted to account for this technology. Our results demonstrate that large parts of risk assessment procedures can be modified, reducing pesticide application and the exposure to the environment. However, further studies and definite procedures are essential to realistically apply, for example, area restriction in the currently required environmental risk assessment schemes. Precision farming has then great potential to achieve the political and public goal of reducing pesticide use, increasing environmental safety, and enhancing the needs of a sustainable agricultural practice. Integr Environ Assess Manag 2023;19:17-23. © 2022 SETAC.

Supercontinuum-based nondisruptive scattering analyses of mouse fibroblast L929 cells before and after necrosis.

The scattering properties of biological tissue are highly dependent on the structure size, refractive index, and wavelength of the incident light. Furthermore, these scattering characteristics are strongly influenced by movements of the scattering objects. A method is developed to determine the angular- and spectral-resolved scattering properties that enabled the characterization of biological nano- and microscaled cell structures. Nanosecond pulses from a spectrally filtered supercontinuum light source are captured and time-resolved to depress background noise and minimize disruptive effects of the biological cells. The scattering characteristics of a monolayer of mouse fibroblast L929 cells are measured at defined wavelengths in a standard cell culture plate. Because of the size and distribution of the scattering structures, a Fourier transform-based Mie scattering scheme is used to analyze the data. The system is tested to detect structural changes of mouse fibroblast L929 cells before and after poisoning with Triton X100. The final result is the development of a contamination-free method to study pathological changes in cell cultures, necrosis, or other cell-damaging effects.

Plant surface wax affects parasitoid's response to host footprints.

The plant surface is the substrate upon which herbivorous insects and natural enemies meet and thus represents the stage for interactions between the three trophic levels. Plant surfaces are covered by an epicuticular wax layer which is highly variable depending on species, cultivar or plant part. Differences in wax chemistry may modulate ecological interactions. We explored whether caterpillars of Spodoptera frugiperda, when walking over a plant surface, leave a chemical trail (kairomones) that can be detected by the parasitoid Cotesia marginiventris. Chemistry and micromorphology of cuticular waxes of two barley eceriferum wax mutants (cer-za.126, cer-yp.949) and wild-type cv. Bonus (wt) were assessed. The plants were then used to investigate potential surface effects on the detectability of caterpillar kairomones. Here we provide evidence that C. marginiventris responds to chemical footprints of its host. Parasitoids were able to detect the kairomone on wild-type plants and on both cer mutants but the response to cer-yp.949 (reduced wax, high aldehyde fraction) was less pronounced. Experiments with caterpillar-treated wt and mutant leaves offered simultaneously, confirmed this observation: no difference in wasp response was found when wt was tested against cer-za.126 (reduced wax, wt-like chemical composition) but wt was significantly more attractive than cer-yp.949. This demonstrates for the first time that the wax layer can modulate the detectability of host kairomones.