RNA interference (RNAi) is a powerful technology that offers new opportunities for pest
control through silencing of genes that are essential for the survival of arthropod pests.
The approach relies on sequence-specificity of applied double-stranded (ds) RNA that
can be designed to have a very narrow spectrum of both the target gene product (RNA)
as well as the target organism, and thus allowing highly targeted pest control. Successful
RNAi has been reported from a number of arthropod species belonging to various
orders. Pest control may be achieved by applying dsRNA as foliar sprays. One of the
main concerns related to the use of dsRNA is adverse environmental effects particularly
on valued non-target species. Arthropods form an important part of the biodiversity
in agricultural landscapes and contribute important ecosystem services. Consequently,
environmental risk assessment (ERA) for potential impacts that plant protection products
may have on valued non-target arthropods is legally required prior to their placement on
the market. We describe how problem formulation can be used to set the context and
to develop plausible pathways on how the application of dsRNA-based products could
harm valued non-target arthropod species, such as those contributing to biological pest
control. The current knowledge regarding the exposure to and the hazard posed by
dsRNA in spray products for non-target arthropods is reviewed and suggestions are
provided on how to select the most suitable test species and to conduct laboratorybased
toxicity studies that provide robust, reliable and interpretable results to support
the ERA.