8 research outputs found

    Short communication. Toxicity of emamectin benzoate to adults of Nesidiocoris tenuis Reuter, Macrolophus pygmaeus (Rambur) and Diglyphus isaea Walker on tomato plants. Semi-field studies.

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    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 B1 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

    Nonsteroidal moulting hormone agonists: effects on protein synthesis and cuticle formation in colorado potato beetle larvae.

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    Larvae of the Colorado potato beetle, Leptinotarsa decemlineata (Say), that were orally treated with RH-0345 at 0.1 mg l?1, RH-5849 at 10 and 50 mg l?1, tebufenozide at 2 g l?1, and 20-hydroxyecdysone at 2 g l?1, showed symptoms of prematuremoulting, followed by inhibition of ecdysis. In addition, fresh weight gain and total protein content were blocked. The effects on haemolymphal and cuticular polypeptides after PAGE were linked with premature, new epicuticle deposition as was observed under the electron microscope. These observations support the concept that the ecdysteroid-mimicking action of the three nonsteroidal molecules is specifi

    Toxicity and sublethal effects of six insecticides to last instar larvae and adults of the biocontrol agents Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) and Adalia bipunctata (L.) (Coleoptera: Coccinellidae)

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    To further develop Integrated Pest Management (IPM) strategies against crop pests, it is important to evaluate the effects of insecticides on biological control agents. Therefore, we tested the toxicity and sublethal effects (fecundity and fertility) of flonicamid, flubendiamide, metaflumizone, spirotetramat, sulfoxaflor and deltamethrin on the natural enemies Chrysoperla carnea and Adalia bipunctata. The side effects of the active ingredients of the insecticides were evaluated with residual contact tests for the larvae and adults of these predators in the laboratory. Flonicamid, flubendiamide, metaflumizone and spirotetramat were innocuous to last instar larvae and adults of C. carnea and A. bipunctata. Sulfoxaflor was slightly toxic to adults of C. carnea and was highly toxic to the L4 larvae of A. bipunctata. For A. bipunctata, sulfoxaflor and deltamethrin were the most damaging compounds with a cumulative larval mortality of 100%. Deltamethrin was also the most toxic compound to larvae and adults of C. carnea. In accordance with the results obtained, the compounds flonicamid, flubendiamide, metaflumizone and spirotetramat might be incorporated into IPM programs in combination with these natural enemies for the control of particular greenhouse pests. Nevertheless, the use of sulfoxaflor and deltamethrin in IPM strategies should be taken into consideration when releasing either of these biological control agents, due to the toxic behavior observed under laboratory conditions. The need for developing sustainable approaches to combine the use of these insecticides and natural enemies within an IPM framework is discussed

    Lethal and sublethal toxicity of Fipronil and Imidacloprid on Psyttalia concolor (Hymenoptera: Braconidae).

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    Psyttalia concolor (Szèpligeti) (Hymenoptera: Braconidae) is a koinobiont endoparasitoid of several species of tephritid (Diptera) 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 treatmen

    Effects of sublethal doses of methoxyfenozide on the development, survival and reproduction of Spodoptera frugiperda.

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    The lethal and sublethal effects of the ecdysone agonist methoxyfenozide on the fall armyworm, Spodoptera frugiperda (J. E. Smith), were investigated by feeding a methoxyfenozide-treated diet to ϐifth instars until pupation in doses corresponding to the LC 10 and LC 25 for the compound. Larval mortality reached 8% and 26% in the low and high concentration groups, respectively, on the seventh day of the experiment. A progressive larval mortality of 12% for the LC 10 and 60% for the LC 25 was observed before pupation. Treated larvae exhibited lower pupal weights, higher pupal mortality, presence of deformed pupae, and more deformed adults than untreated larvae. The incorporation of methoxyfenozide into the diet had a signiϐicant effect on the timing of larval development. The development period for males and females was about seven days longer than the controls for both concentrations tested. In contrast, the compound affected neither pupae nor adult longevity. Finally, S. frugiperda adults that resulted from ϐifth instars treated with methoxyfenozide were not affected in their mean cumulative number of eggs laid per female (fecundity), nor percentages of eggs hatched (fertility), or the sex ratio. Our results suggest that the combination of lethal and sublethal effects of methoxyfenozide may have important implications for the population dynamics of the fall armywor

    Compatibilidad de modernos insecticidas sobre el depredador generalista Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae)

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    La Directiva 2009/128/CE sobre Uso Sostenible de Plaguicidas establece que los Programas de Manejo Integrado de Plagas (MIP) deben dar prioridad a los métodos de control físicos y biológicos, y que las materias activas insecticidas aplicadas deberán ser selectivas con la plaga y respetuosas con los organismos beneficiosos. El neuróptero generalista Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) es ampliamente utilizado en MIP porque controla eficazmente pulgones y otros pequeños artrópodos. Además, se trata de una de las especies de referencia consideradas por la OILB en la evaluación de los efectos secundarios de plaguicidas, cuando en la primera secuencia de evaluación resultan tóxicos los compuestos. En este trabajo se evaluó la compatibilidad de nuevos insecticidas con diferentes modos de acción sobre larvas L3 y adultos del depredador C. carnea. Las materias activas ensayadas están incluidas, o en proceso de inclusión en el Anexo I de la Directiva 91/414/EEC: flonicamida (inhibidor selectivo de la alimentación), flubendiamida (modulador del receptor de rianodina), metaflumizona (bloqueador del canal de sodio), spirotetramat (inhibidor de lípidos), sulfoxaflor (modo de acción desconocido) y deltametrina (modulador del canal de sodio). Los ensayos se realizaron exponiendo los insectos a residuo fresco de los diferentes compuestos sobre placa de vidrio tratada, en condiciones de laboratorio, aplicando la dosis máxima de campo recomendada de cada insecticida mediante Torre de Potter. Se evaluó mortalidad larvaria (24-48-72 h), pupación, emergencia y mortalidad de adultos, así como fecundidad y fertilidad (durante 7 días). En adultos se evaluó mortalidad (24-48-72 h), fecundidad y fertilidad (durante 7 días)

    Ecotoxicity of insecticides of frequent use in tomatoes on Trichogramma achaeae (Hymenoptera: Trichogrammatidae)

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    Since Tuta absoluta(Meyrick) (Lepidoptera: Gelechiidae) was detected in 2006 as a new pest in tomato crops in Spain, several natural enemies have been reported tocontrol this pest. In biological control programs, the native parasitoid Trichogramma achaeae Nagaraja&Nagarkatti (Hymenoptera: Trichogrammatidae) is used against T.absoluta. However, the most common control practice is based on use of pesticides,and in the frame of Integrated Pest Management (IPM) programs, the knowledge on the activity of insecticides towards beneficial insects is needed for its joint use. In thiswork, we evaluated lethal and sublethal effects of insecticides commonly applied on tomato crops on adults of T. achaeae. Pesticides were sprayed on tomato plants or T. Absoluta eggs till run off at their maximum field recommended concentration. Mortality was scored after 24, 48 and 72 hours, as well as beneficial capacity and percentage of emergence

    Side effects of modern pesticides on adults of the predatory mite Amblyseius swirskii (Athias-Henriot) (Acari: Phytoseiidae) under laboratory conditions

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    Amblyseius swirskii (Athias-Henriot) is a polyphagous predatory mite which feeds on pollen and small arthropod preys like whiteflies, thrips and mites. This species is widely used in IPM programs in greenhouses, being essential for its success, to obtain information about the non target effects of the pesticides currently used in those crops where the mite is artificially released. This work describes a laboratory contact residual test for evaluating lethal (mortality after 72 hour exposure to fresh residues) and sublethal effects (fecundity and fertility of the surviving mites) of eleven modern pesticides to adults of A. swirskii. Spiromesifen is lipogenesis inhibitor; flonicamid a selective feeding inhibitor with a mode of action not totally known; flubendiamide a modulator of the rhyanodin receptor, sulfoxaflor has a complex mode of action not totally ascertained; metaflumizone is a voltage dependent sodium channel blocker; methoxyfenozide is an IGR, spirotetramat inhibits lipids; abamectin and emamectin activate the Cl- channel; spinosad is a neurotix naturalyte and deltamethrin a pyrethroid used as positive standard. Selected pesticides are effective against different key pests present in horticultural crop areas and were always applied at the maximum field recommended concentration in Spain if registered, or at the concentration recommended by the supplier. Out of the tested pesticides, spiromesifen, flonicamid, flubendiamide, sulfoxaflor, metaflumizone, methoxyfenozide and spirotetramat were harmless to adults of the predatory mite (IOBC toxicity class 1). The rest of pesticides exhibited some negative effects: emamectin was slightly harmful (IOBC 2), deltamethrin moderately harmful (IOBC 3) and spinosad and abamectin harmful (IOBC 4). Further testing under more realistic conditions is needed for those pesticides having some harmful effect on the mite prior deciding their joint use or not. Key words: Amblyseius swirskii, adults, laboratory, residual test, spiromesifen, flonicamid, flubendiamide, sulfoxaflor, metaflumizone, methoxyfenozide, spirotetramat, emamectin, deltamethrin, abamectin, spinosad
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