Deliverable 28: Specification of low risk products REBECA ...

For a given chemical pesticide, the dispersal factor would be calculated by
determining the maximum dispersal distance and quantity, taking into account spray
drift, run-off and leaching, dispersal via bioaccumulation, and through evaporation.
Similarly, when scoring for micro-organisms spray drift, leaching and run-off will be
considered. Additionally, the dispersal through infected organisms must be
accounted for, as this can involve the transport of significant quantities of infectious
material over long distances.
In the absence of more detailed knowledge the following generalized worst case
assumptions are applied: for spray applications, drift is assumed to disperse 10 % of
the applied active ingredient up to 100 m (Pest Management Regulatory Agency,
2007); for microbials pathogenic to insects, unless other information is available, a
dispersal distance of up to 1000 m is assumed due to the possibility of infected
insects spreading the inoculum.
Range of non target effects. Most bacteria and fungi have, under certain
conditions, the potential to act as opportunistic pathogens and infect species
normally not susceptible to the organism. These conditions include high inoculum
concentrations, climatic conditions suitable for the micro-organism, and/or
circumstances under which the immune response of the potential host is weakened.
It is, therefore, important to differentiate between the physiological and the ecological
host range (Onstad & McManus, 1996; Jaronski et al., 1998; Jaronski et al., 2003;
Meyling et al., 2005). For an environmental risk assessment only the ecological host
range of a biological control agent is of interest. As a consequence, laboratory
studies on non-target organisms should be designed to reflect natural conditions.
Likewise for chemicals, the target range assessment should be done at
concentrations realistic for a typical application scenario. Where available NOEL
levels, dose-response curves or risk quotients (estimated environmental
concentration over toxicity) should be used for this assessment.
Table 3 Assignment of scores for non-target effects. Modified from Hickson et al.
(2000) and Hokkanen et al. (2003) to better suit the inclusion of chemical pesticides
in the proposed system.
Range of non-target effects
Score Likelihood Magnitude
1 1 species Genus
2 2-3 species Family
3 4-10 species Order
4 11-30 species Class
5 > 30 species >= Phylum
Once the range of possible affected non-targets is determined, the score in this
category can be calculated as described in Table 3. Should significant indirect effects
occur, the number of affected species (irrespective of the taxonomic level) must be
included when scoring for the range of non-target species.
While the scoring guidance for non-targets described above is relatively
straightforward, the antagonistic suppression of microbial growth to control plant
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