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The insect toxicity assays demonstrated that MACs are selective for O. laevigatus. The modelling/docking experiments are indications that these pesticides do not bind with the LBD-EcR of O. laevigatus and support the supposition that they show no biological effects in the predatory bug. These data help in explaining the compatible use of MACs together with predatory bugs in IPM programmes.

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Psyttalia concolor (Szépligeti) (Hymenoptera: Braconidae) is a koinobiont endoparasitoidof several species of tephritid (Díptera) larvae, such as Bactrocera oleae (Gmelin) and Ceratitis capitata (Wiedemann). Here, we report on the effects of imidacloprid and fipronil on P. concolor females, when different routes of exposure were evaluated: residual contact (cover and bait sprays) and via treatment of host species. Moreover, the persistence of the bait formulated compound also was studied. For each experiment, lethal (mortality) and sublethal effects (parasitization rate or longevity) were studied. Fipronil produced 100% mortality irrespective of exposure route, and it was very persistent, because 34-d-old residues still produced this high mortality rate, being as toxic or even more toxic than the reference product dimethoate. Toxicity of imidacloprid depends on the mode of exposure, although always remained less toxic than dimethoate. Imidacloprid caused high mortality or sublethal effect to the progeny in cover sprays and when applied via treated host, being harmless in bait sprays application. In conclusion, our results suggest that fipronil should not be used in the field when the parasitoid is present. On the contrary, although imidacloprid is physiologically active against females of P. concolor, ecological selectivity may result through the use of bait treatment.

Whiteflies, the tomato borer and leafminers are among the major pests of greenhouse tomatoes in Spain. Macrolophus pygmaeus (Heteroptera, Miridae) and Nesidiocoris tenuis are polyphagous predators of whiteflies, the tomato borer and other pests. Diglyphus isaea (Hymenoptera, Eulophidae) is an ectoparasite of leafminers. These three natural enemies are commonly released in the commercial horticultural greenhouses of south-eastern Spain. Emamectin benzoate is a new semi-synthetic derivative of the avermectin B 1 developed for Lepidoptera pest control in vegetable crops, with requested inclusion in annex I of the EU directive 91/414/EEC. As for any new insecticide that is being introduced for its use in protected tomato, it is critical to understand the level of compatibility of emamectin in front of those major biological control agents. Potted tomato plants kept in a greenhouse were sprayed with the highest recommended field rate of emamectin benzoate (14.25 mg L -1 ), and the toxicity of fresh and 7-day-old residues to adults of the three biological control agents were studied to ascertain their compatibility. The results demonstrated the compatibility of both fresh and 7-day-old residues with the three species of natural enemies.Additional key words: avermectins; biological control; greenhouse; leafminers; whiteflies. ResumenComunicación corta. Toxicidad del benzoato de emamectina sobre adultos de Nesidiocoris tenuis Reuter, Macrolophus pygmaeus (Rambur) (Heteroptera: Miridae) y Diglyphus isaea Walker (Hymenoptera: Eulophidae) en plantas de tomate. Estudios de semi-campo La mosca blanca, la polilla y el minador de la hoja del tomate son algunas de las plagas más importantes de los invernaderos españoles. Macrolophus pygmaeus (Heteroptera: Miridae) y Nesidiocoris tenuis son depredadores polí-fagos de la mosca blanca, la polilla y otras plagas del tomate. Diglyphus isaea (Hymenoptera: Eulophidae) es un ectoparasitoide del minador de la hoja. Estos tres enemigos naturales se usan comúnmente en sueltas inoculativas en invernaderos comerciales del sureste español. Benzoato de emamectina es un derivado semi-sintético de la avermectina B 1 , desarrollado para el control de plagas de lepidópteros en cultivos hortícolas que está siendo revisado para su inclusión en el Anejo I siguiendo la directiva EU 91/414/EEC. Al igual que para todos los insecticidas de nueva introducción en el cultivo del tomate protegido, es fundamental el conocimiento del nivel de compatibilidad del benzoato de emamectina frente a los agentes de control biológico más utilizados en este ámbito. Se aplicó el insecticida benzoato de emamectina a la dosis máxima recomendada (14,25 mg L -1 ) sobre plantas de tomate en invernadero para evaluar la toxicidad del residuo fresco y de siete días del insecticida sobre adultos de estos tres agentes de control biológico. Los resultados demuestran que tanto el residuo fresco como el de siete días son compatibles con las tres especies estudiadas.Palabras clave adicionales: avermectinas; control biológico;...

The insect toxicity assays demonstrated that MACs are selective for P. concolor. The modelling/docking experiments are indications that these insecticides do not bind with the LBD-EcR of P. concolor and support the theory that they show no biological effects in the parasitic wasp. These data may help in explaining the compatible use of MACs together with parasitic wasps in IPM programmes.