Biological control agents (biorationals) are increasingly important in pest control concepts. Certain insect viruses, particularly the baculoviruses (nuclear polyhedrosis viruses), are considered to have potential as biological pesticides, and could be used widely in the environment. Therefore, test animals must be selected and methods developed to evaluate the safety of biorationals to non-target species. A simple laboratory system has been designed and tested to determine risks of infectivity and pathogenicity of an insect Baculovirus, originally isolated from the Alfalfa looper Autographa californica, to a non-target arthropod, the grass shrimp, Palaemonetes vulgaris, by dietary exposure. This laboratory method also permits testing of other microbial biorationals against non-target aquatic species, and provides an inexpensive, procedure of safety testing.