This study assessed the transgenerational effects of insecticides in developing Trichogramma galloi (Hymenoptera: Trichogrammatidae). Laboratory bioassays were performed in which five insecticides were sprayed on egg-larval, pre-pupal and pupal stages of the parasitoid. The interaction between insecticides and development stages of the parasitoid was not significant for the rate of F0 emergence. All insecticides significantly reduced the emergence of wasps, with the lowest emergence observed when they were applied to the pupal stage. For the sex ratio, only spinosad applied to the pre-pupal stage and triflumuron applied on the egg-larval and pre-pupal stages did not differ from the controls. Triflumuron applied to pre-pupae did not lead to any difference in the parasitism rate of the treated generation (F0) when compared to the control. There were no significant differences among survival curves for females of F0 when all insecticides were sprayed on the egg-larval stage. Both concentrations of lambda-cyhalothrin + thiamethoxam reduced female pre-pupal survival, and all treatments reduced female pupal survival. In addition, we observed a transgenerational effect of the insecticides on emergence and sex ratio of next generation (F1). Lambda-cyhalothrin + thiamethoxam (Min) applied to the pre-pupae and pupae, the maximum rate of the same insecticides applied to the egg-larvae and pre-pupae, and spinosad applied to pre-pupae all significantly reduced the adults emergence of T. galloi F1 generation. Only triflumuron did not alter the F1 sex ratio. These bioassays provide a basis for better understanding the effects of insecticide use on beneficial parasitoids.

The predatory bug Orius insidiosus is an important biological control agent of several insect pests, and is one of the most commonly used species in biological control programs worldwide. This study assessed the lethal and sublethal effects of insecticides on this species through life table, and classified the insecticides according to the definitions of toxicity given by the International Organization for Biological and Integrated Control of Noxious Animals and Plants (IOBC). A bioassay was carried out using a completely randomized design with eight treatments and 40 replicates. Eggs of O. insidiosus laid naturally in plant stems were immersed in aqueous solutions of the chemical products. Egg viability, duration of the embryonic period, survival of nymphs, and duration of the nymphal period were assessed daily. Insects that reached adulthood were paired and their reproduction assessed. The number of eggs produced and the survival of adults were assessed daily. The insecticides abamectin, cartap hydrochloride, spirotetramat+imidacloprid, and flubendiamid were classified as harmful. Pyriproxyfen and rynaxypyr were categorized as harmless and pymetrozine was classified as slightly harmful. Pyriproxyfen affected the population parameters rm, GT, DT, and λ, whereas other insecticides did not.

The treatment of seeds with systemic insecticides has become a common practice worldwide. However, this prophylactic use of insecticides has been questioned recently because of the potential risks to non-target organisms. This study assessed the non-target effects of chlorantraniliprole and thiamethoxam seed treatments on the life history and walking behavior of Podisus nigrispinus (Dallas), as well as the efficacy of these insecticides for controlling Spodoptera frugiperda (Smith). Thiamethoxam caused mortality of P. nigrispinus, increased the pre-oviposition period, and reduced the oviposition period and the fecundity and survival of females compared to chlorantraniliprole. In contrast, the life expectancy of P. nigrispinus females was prolonged by chlorantraniliprole, which also increased the intrinsic rate of growth (r) and the finite growth rate (λ), and reduced the population doubling time (DT) compared to thiamethoxam. The net reproductive rate (R) and mean generation time (T) were not affected by either insecticide treatment, and neither were the walking velocity of P. nigrispinus females, nor the distance they covered. Both chlorantraniliprole and thiamethoxam reduced soybean leaf consumption by S. frugiperda larvae. Given the observed lethal and sublethal effects, soybean seed treatments with chlorantraniliprole and thiamethoxam were judged to present low and moderate risks for P. nigrispinus, respectively.

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Extrato metanólico de folhas de mandioca como alternativa ao controle da lagarta-do-cartucho e de formigas cortadeiras Cassava leaf methanolic extract as an alternative to control of fall armyworm and leaf cutter ants Resumo Objetivou-se neste trabalho caracterizar os compostos fenólicos e avaliar o efeito, em condições de laboratório, do extrato metanólico do pó de folhas de mandioca sobre o desenvolvimento da lagarta-docartucho S. frugiperda e da saúva-limão Atta sexdens rubropilosa. O referido extrato, nas concentrações de 250, 500, 1000 e 1500 mg kg -1 , foi incorporado na dieta artificial, a qual foi exposta a lagarta para avaliar características biológicas. Logo após a emergência dos insetos, outro experimento foi realizado para verificar a possível atividade subletal do extrato, para isso casais de S. frugiperda foram isolados em gaiolas e as posturas foram recolhidas para a quantificação. O extrato de Manihot esculenta Crantz provocou redução na porcentagem de sobrevivência das lagartas, bem como no número de ovos. A seguir o mesmo extrato foi solubilizado em etanol 10% e aplicado em formigas, observou-se a mortalidade em comparação com a testemunha. Conclui-se que o extrato metanólico do pó de folhas de M. esculenta Crantz, contendo ácido gálico e catequina, apresenta-se como uma alternativa promissora ao controle de S. frugiperda e de Atta sexdens rubropilosa. AbstractThe objective of this study was to characterize phenolic compounds and evaluate the effect, under laboratory conditions, of the cassava leaf powder methanol extract on the development of fall armyworm Spodoptera frugiperda and of leaf-cutting ant Atta sexdens rubropilosa. The extract was incorporated into an artificial diet, to which the armyworm was exposed, at concentrations of 250, 500, 1000 and 1500 mg kg -1 , in order to evaluate biological characteristics. Soon after the insects emergence, another experiment was conducted to verify the possible sub lethal activity of the extract; therefore, S. frugiperda couples were isolated in cages and eggs were collected and counted. The Manihot esculenta Crantz extract caused a reduction in the percentage of armyworm survival, as well as in the eggs number. Then, the same extract was solubilized in 10% ethanol and applied to ants; mortality was observed, compared to the control. It is possible to conclude that the M. esculenta Crantz leaf powder methanolic extract, containing gallic acid and catechin, is a promising alternative to control S. frugiperda and Atta sexdens rubropilosa.

BACKGROUND: Thiamethoxam, when applied as a seed treatment, can contaminate plant products, such as extrafloral nectar, and have non-target effects on beneficial arthropods. This study assessed the non-target effects of thiamethoxam applied to cotton seed on the life history parameters of the predators Chrysoperla externa (Neuroptera: Chrysopidae) and Harmonia axyridis (Coleoptera: Coccinellidae). RESULTS: Exposure of C. externa larvae to plants grown from thiamethoxam-treated seeds caused sublethal and transgenerational effects. Thiamethoxam treatment doubled the proportion of pharate adults and reduced egg fertility in C. externa F0 and F1 generations. In addition, the insecticide prolonged pupal developmental time in the C. externa F1 generation. Thiamethoxam treatment also had a transgenerational effect on exposed H. axyridis larvae, reducing pupal survival in the F1 generation. In the adult bioassay, thiamethoxam treatment reduced egg fertility of C. externa, prolonged the larval period, and reduced both fecundity and egg fertility of the F1 generation. Thiamethoxam also caused transgenerational effect on H. axyridis adults, reducing larval survival of the F1 generation.CONCLUSION: Thiamethoxam seed treatment was harmful for both predators, but C. externa was more affected by the insecticide than H. axyridis.

Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) is considered a pest of maize crops throughout the Western Hemisphere. We report on the effects of aqueous extracts of leaves and bark of Copaifera langsdorffii (Fabaceae) on the biology of S. frugiperda, as an alternative source of natural bioactive molecules for the sustainable management of this pest. Second instars were sprayed with aqueous extracts prepared with 5% (w/v) plant material and/or fed on an artificial diet containing extracts at a concentration equivalent to 0.25% (w/v) for 17 days. Both leaf and bark extracts of C. langsdorffii significantly reduced S. frugiperda food intake, feces, and larval weight and caused a delay in larval development. Additionally, C. langsdorffii-based extracts increased the oviposition period; induced morphological changes in the eggs, including deformation of the corium and malformation of the micropylar and aeropylar regions; and reduced egg viability. But, aqueous extracts of C. langsdorffii exhibited no negative effects on larval and pupal survival, duration of the pupal stage, survival of pupae, sex ratio, longevity, duration of pre-oviposition period, and female fecundity. Aqueous extracts of leaves and bark of C. langsdorffii are promising alternatives for the control of S. frugiperda in maize crops.