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The 6/04 standard of the European and Mediterranean Plant Protection Organisation (EPPO) on the safe use of biological control is a decision-support scheme (DSS) for the import and release of biological control agents in Europe. It was recently developed by the Joint EPPO/International Organisation of Biological Control (IOBC) Panel on Biological Control Agents. The DSS can be used to assess the potential environmental impacts of biological control agents. It is valid for different types of biological control: classical and augmentative biological control of invertebrates, pathogens and weeds. However, the DSS is not yet widely implemented in Europe and, during preliminary trials, it was found that its broad range of usages could lead to some confusion or misunderstandings, as well as requiring unnecessary information in some cases. Thus, the scheme was modified to specifically assess classical biological control against plant pests, i.e. the introduction of exotic natural enemies of plant pests for establishment and long-term control. The new version of the scheme was then tested on two parasitoids that are presently being released in Europe, the figitid Ganaspis cf. brasiliensis against the spotted wing drosophila Drosophila suzukii and the mymarid Cleruchoides noackae against the Eucalyptus bronze bug Thaumastocoris peregrinus. Both parasitoids were successfully assessed with the new version of the DSS. No major issues were encountered during the assessments and most questions were answered with low levels of uncertainty. Both assessments concluded that the parasitoids were safe to release in the impact assessment areas, with positive impacts exceeding negative impacts. Suggestions for potential improvements are provided. [ABSTRACT FROM AUTHOR]

Classical biological control, i.e., the introduction of natural enemies from an invasive pest's area of origin, has been proposed repeatedly to control the spotted wing drosophila Drosophila suzukii in the Americas and in Europe. Results from surveys in Asia and laboratory experiments suggest the parasitoid G1 Ganaspis cf. brasiliensis as a suitable biological control agent. To study the host specificity of the parasitoid under semi-field conditions, we conducted large-arena field cage releases. Parasitoids were released into cages at three dates in August 2021 in two regions of Switzerland. Released parasitoids had the choice to parasitize either D. suzukii larvae in fresh fruits (blueberries or elderberries) or the non-target native species D. melanogaster in decomposing fruits. The results were unequivocal in that apparent parasitism of D. suzukii larvae feeding in fresh fruits was on average 15%, whereas only one parasitoid emerged from D. melanogaster feeding on decomposing fruits (0.02% parasitism). Thus, the results support findings from previous laboratory experiments that G1 G. cf. brasiliensis is highly specific to D. suzukii larvae feeding in fresh fruits and parasitism of the closely related D. melanogaster feeding on decomposing fruits is very rare. Because in its invaded range, D. suzukii is the only Drosophila species that can attack and develop in undamaged fresh fruits, we conclude that open field releases of the parasitoid G1 G. cf. brasiliensis should not pose significant risks to non-targets. [ABSTRACT FROM AUTHOR]

Simple Summary: The silver fly Neoleucopis kartliana Tanasijtshuk (Diptera, Chamaemyiidae) is the most abundant predator of the giant pine scale (GPS), Marchalina hellenica (Hemiptera, Margarodidae), and is considered a major factor in controlling GPS populations in Greece and Turkey. GPS has recently been detected in Australia. While generally not harmful to trees in its area of origin, GPS has a detrimental impact on pine trees in Australia and, therefore, needs to be controlled. As part of an evaluation of the silver fly for importation to Australia where it may be used as a biological control agent against GPS, we studied several aspects of the fly's life history, namely its seasonal occurrence and number of generations per year (phenology), its acceptance of artificial food sources as adult flies, and the number of eggs females produce over their lifetime. We found that the fly has three generations per year and feeds on all life stages of GPS (eggs, nymphs, and adults). Adults readily feed on a mixture of sugar and dry yeast, and females emerge with no or few eggs and develop more as they age. Neoleucopis kartliana Tanasijtshuk (Diptera, Chamaemyiidae) is the most abundant predator of the giant pine scale (GPS), Marchalina hellenica (Hemiptera, Margarodidae) in Greece. GPS is native to Greece and Turkey, where it is not considered a pest of Pinus spp., but a valuable resource for pine honey production. However, its introduction to new areas leads to high population densities of the scale, linked to declines in tree health and insect biodiversity. To assess the potential use of N. kartliana for a classical biological control program in Australia, we studied selected life-history traits of the silver fly, namely its phenology in northern Greece, feeding preferences of adult flies on artificial food sources, and potential fecundity of female flies. The silver fly was present in every site in northern Greece studied and was found to have at least three generations per year in this area. The fly's overall sex ratio was 1:1, and adult females emerged with no or few mature eggs in their ovaries, but egg production was exponential until at least the eighth day after emergence. These findings increase our knowledge about the biology of N. kartliana and aided in the evaluation of the silver fly as a classical biological control agent against invasive GPS in Australia. [ABSTRACT FROM AUTHOR]

[Display omitted] • Leucopis hennigrata is a promising candidate for biological control of Adelges nordmannianae in Northern Europe. • L. hennigrata is a key predator of Ad. nordmannianae in Western Asia and Central Europe. • Under laboratory conditions larvae of L. hennigrata killed 57–117 eggs in 24 h. • Adult L. hennigrata oviposited on various non-target species, but rarely completed development. • Leucopis hennigrata was not found from non-target adelgids or aphids in the field. The silver fly Leucopis hennigrata McAlpine is a predator of the silver fir wooly adelgid, Adelges nordmannianae (Eckstein), a pest in the European production of Christmas trees. While the fly is known to be a common native predator of the adelgid in Georgia, Turkey, and central Europe, it is absent from northern Europe, where the Christmas tree production is an important industry. Therefore, L. hennigrata has been suggested as a classical biological control agent of Ad. nordmannianae in northern Europe. Here, we evaluated the fly's suitability as a classical biological control agent in terms of (1) differences between Asian and European populations, (2) its abundance relative to other predators of Ad. nordmannianae , (3) larval feeding efficacy, as well as (4) the physiological and (5) ecological prey preference of the fly. The results showed that despite genetic divergence between Western Asian and Central European populations, L. hennigrata is a dominant natural enemy of Ad. nordmannianae in Switzerland, the Pontic mountains in northern Turkey, and in the Greater and Lesser Caucasus mountains. Larvae of L. hennigrata killed on average 57–117 eggs in 24 h, depending on their size, the number of eggs offered to them, and possibly some environmental factors. In no-choice tests, adult flies oviposited on twigs containing different non-target adelgid, aphid, and scale insect species. Larvae of L. hennigrata were observed to feed on several of them. However, only the non-target species Mindarus abietinus Koch supported development of a single specimen to the adult stage. During field surveys in Switzerland and Georgia, L. hennigrata was never found on any sampled non-target species. Based on our findings, we conclude that L. hennigrata is a suitable classical biological control agent because it (1) is already present in countries that neighbor northern Europe, (2) is a dominant natural enemy of the pest in Switzerland, (3) is an efficient predator of the pest's eggs, and (4) seems to be specific to Ad. nordmannianae in its ecological range. [ABSTRACT FROM AUTHOR]