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Event MIR604 maize expresses a modified Cry3A protein (mCry3A), for control of corn rootworm. As part of the environmental safety assessment of MIR604 maize, risks to non-target organisms of mCry3A were assessed. The potential exposure of non-target organisms to mCry3A following cultivation of MIR604 maize was determined, and the hypothesis that such exposure is not harmful was tested. The hypothesis was tested rigorously by making worst-case or highly conservative assumptions about exposure, along with laboratory testing for hazards using species taxonomically related to the target pest and species expected to have high exposure to mCry3A, or both. Further rigour was introduced by study designs incorporating long exposures and measurements of sensitive endpoints. No adverse effects were observed in any study, and in most cases exposure to mCry3A in the study was higher than the worst-case expected exposure. In all cases, exposure in the study was higher than realistic, but still conservative, estimates of exposure. These results indicate minimal risk of MIR604 maize to non-target organisms.

SUMMARY Winter wheat fields on two farms in West Sussex were sampled in 1980 and 1981 for cereal aphids and their natural enemies. The grain aphid, Sitobion avenae was present in all 19 fields examined, but in no case did the populations increase to densities liable to cause economic damage. The observations strongly suggest that aphid population growth was stopped by aphid‐specific predators, hymenopterous parasitoids and fungal pathogens. In two fields in 1980, S. avenae population densities approximately equalled five aphids per ear at flowering, the threshold at which insecticide application is recommended in the UK, but numbers were then reduced by natural enemies, mainly aphid‐specific predators. In three fields in 1981, S. avenae would probably have exceeded the spray threshold had natural enemies not intervened in late May.

SUMMARY ‘Banker’ plants on which a whitefly/parasite interaction had been well established successfully controlled glasshouse whitefly (Trialeurodes vaporariorum (Westw.)) when introduced on to a commercial tomato crop at rates of 89 or 50 plants per hectare. Each plant produced about 8000 parasites over a minimum period of eight weeks and the presence of whiteflies and honeydew on these plants provided the adult parasites with a source of food during the early stages of the infestation. The principal advantages of the ‘banker’ system over existing methods in which parasites are introduced on detached leaf material are the ease of rearing the parasites and the need for only a single introduction to the glasshouse.

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