The interplay between temperature and an insecticide mixture modulates the stimulatory response of sublethally exposed Myzus persicae.

Temperature can interact with chemical pesticides and modulate their toxicity. Sublethal exposure to pesticides is known to trigger hormetic responses in pests. However, the simultaneous effects of temperature and sublethal exposure to single or mixture-based insecticides on the insects' stimulatory responses are not frequently considered in toxicological studies. Here we investigated the combined effects of temperature on the lethal and sublethal responses of the green peach aphid Myzus persicae after exposure to commercial formulations of a neonicotinoid (thiamethoxam) and a pyrethroid (lambda-cyhalothrin) and their mixture. Firstly, the concentration-response curves of the insecticides were determined under four temperatures (15 °C, 20 °C, 25 °C, and 28 °C) by the leaf dipping method. Subsequently, the sublethal concentrations C0, CL1, CL5, CL10, CL15, CL20, and CL30 were selected to assess sublethal effects on aphids' longevity and reproduction under the same temperatures. The results showed that the mixture of thiamethoxam + lambda-cyhalothrin caused greater toxicity to aphids compared to the formulations with each active ingredient alone and that the toxicity was higher at elevated temperatures. Furthermore, the exposure to low concentrations of the mixture (thiamethoxam + lambda-cyhalothrin) and the separated insecticides induced stimulatory responses in the longevity and fecundity of exposed aphid females, but the occurrence of such hormetic responses depended on the insecticide type, its sublethal concentration, and the temperature as well as their interactions.

Body Part Selection for Size Classification of Two Trichogramma Species.

Body size is an important morphological characteristic that covaries with the quality of parasitoids and predators. Data show that the larger the organism is, the better the biological parameters and the host location by natural enemies in the field. The standard way of evaluating the size of parasitoids of the genus Trichogramma (Hymenoptera: Trichogrammatidae) is by measuring the tibia, but using only one body part to estimate the size of organisms can lead to miscalculations. In this paper, commercial Trichogramma pretiosum Riley, 1879 (Hymenoptera: Trichogrammatidae) and Trichogramma galloi Zucchi, 1988 (Hymenoptera: Trichogrammatidae) were mounted on slides for microscopy and photographed, and the photographs were used to measure their antennae, scutellum, ovipositor, tibia, and wing. Principal component analysis (PCA) and linear discriminant analysis (LDA) were performed to select the body part that best represents their size. PCA showed that all body parts represented size in a similar way, and LDA showed that the ovipositor was the most representative. We conclude that the best body parts for representing the size of the Trichogramma species studied are the wing and ovipositor, and at least two body parts are needed to detect two size groups.

Mentha spp. essential oils: toxicity to Alphitobius diaperinus, activity against poultry pathogenic bacteria, and Beauveria bassiana compatibility.

The botanical insecticide market is growing because of limitations placed on the use of certain synthetic chemical insecticides. In this sense, the lesser mealworm Alphitobius diaperius (Coleoptera: Tenebrionidae) is the main poultry pest. The insect causes weight loss and damage to the digestive system of poultry, and it is a vector and reservoir of pathogens. Consequently, this study explored the following hypotheses: (i) essential oils (EOs) derived from Mentha spp. are toxic to A. diaperius; (ii) these EOs are compatible with Beauveria bassiana, the natural enemy of the poultry pest, that parasite A. diaperinus; (iii) these EOs also exhibit activity against bacteria that are pathogenic to poultry. In topical applications and ingestion tests, EOs from Mentha arvensis, Mentha spicata, and Mentha piperita were toxic to A. diaperinus. Chromatographic analyses revealed that menthol is the predominant compound in M. arvensis and M. piperita, whereas carvone is the major compound in M. spicata. Both (-)- and (+)-menthol, along with (-)- and (+)-carvone, underwent testing with A. diaperinus. Nevertheless, their activity was not as potent as those of the EOs, suggesting a possible synergistic and/or additive effect. The EOs did not have any adverse effects on the conidial germination, vegetative growth, or conidia production per colony of the entomopathogenic fungus B. bassiana. Consequently, these EOs are compatible with this natural enemy. The EO extracted from M. spicata exhibited significant toxicity against Staphylococcus aureus (ATCC 25923), whereas the remaining EOs displayed moderate toxicity against this bacterium. The EOs derived from Mentha spp., as assessed in this study, hold promise for the development of botanical insecticides tailored for the control of A. diaperinus. These insecticides are selective in favor of the natural enemy B. bassiana and can also serve as effective sanitizers, thanks to their antibacterial properties.

Response of Doru luteipes (Dermaptera: Forficulidae) to insecticides used in maize crop as a function of its life stage and exposure route.

The present study aimed to evaluate insecticide toxicity to Doru luteipes (Scudder), a major predator of maize pests. Lethal and sublethal effects were assessed on nymphs and adults exposed to the insecticides through contact (maize leaves) and ingestion (prey eggs) routes. Tested insecticides included a biopesticide (Spodoptera frugiperda multiple nucleopolyhedrovirus, SfMNPV), modern (flubendiamide and metaflumizone), and older neurotoxins (imidacloprid + ß-cyfluthrin). The imidacloprid/ß-cyfluthrin mix was highly toxic (100% mortality) to the predator, regardless of the exposure route and predator stage. Metaflumizone caused mortality higher than 95% and 45% of nymphs and adults. Flubendiamide and SfMNPV were the least toxic insecticides, not differing from the untreated control in any of the assessed endpoints. Adult tibial length did not differ among treatments. Metaflumizone impaired egg consumption by nymphs and walking distance of adult D. luteipes. Overall, the insecticides caused a more pronounced effect on D. luteipes nymphs than on adults and were more toxic by the contact route. From these findings, flubendiamide and SfMNPV are safer for D. luteipes and should head insecticide choice in integrated pest management programs in maize.

Comparative Tolerance Levels of Maize Landraces and a Hybrid to Natural Infestation of Fall Armyworm.

Insect pests such as Spodoptera frugiperda cause significant losses to maize (Zea mays mays). Control of S. frugiperda is difficult, but the use of insect resistant cultivars, including tolerant cultivars, is a promising alternative, and landraces are a potential source of insect resistance. This study investigated tolerance to S. frugiperda in five Brazilian landraces, Amarelão, Aztequinha, Branco Antigo, Palha Roxa, and São Pedro, in relation to one conventional (non-Bt) hybrid, BM207, under field conditions. We assessed tolerance as the ratio of insecticide-free to insecticide-protected plants for plant height, stem diameter, and leaf chlorophyll content at two plant stages. Tolerance ratios varied across the maize genotypes, but inconsistently across plant variables, and cluster analysis revealed three groups based on tolerance ratios. A first group contained genotypes similarly tolerant to S. frugiperda, BM207, Palha Roxa, São Pedro, and Aztequinha, while the second and third groups each contained single genotypes, Amarelão, and Branco Antigo, which were considered not tolerant. Overall, the landraces Palha Roxa, São Pedro, and Aztequinha compared favorably to BM207 in terms of tolerance, and therefore may be valuable for management of this pest, and as germplasm sources to improve tolerance in other cultivars.

Side effects of insecticides applied to cotton on adult Trichogramma pretiosum by three exposure routes.

BACKGROUND: Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) is released in extensive areas cultivated with cotton worldwide, but the use of synthetic insecticides threatens the establishment of augmented populations. Thus, an assessment of insecticides' effects on T. pretiosum is required to establish their compatibility with mass releases of the parasitoid. We studied in the laboratory the impact of insecticides administered through different exposure routes (direct-spraying, ingestion and residue contact) on T. pretiosum. Based on their toxicity, the insecticides were rated into four categories (harmless, slightly harmful, moderately harmful and harmful) as per the International Organization for Biological Control. RESULTS: The survival, parasitism ability and emergence of the treated adults and offspring (F1 and F2 ), in addition to the persistence of the toxic effects in semi-field conditions, were assessed. Teflubenzuron did not reduce female survival and caused a lesser impact on T. pretiosum on both direct-spraying and ingestion bioassays. In the residue contact bioassay, teflubenzuron and flupyradifurone were rated as harmless and slightly harmful, respectively. The other active substances (chlorfenapyr, thiodicarb and methomyl) were harmful to the parasitoid by all exposure routes and were persistent (with toxicity duration surpassing 30 days). CONCLUSION: From these findings, teflubenzuron is the insecticide most compatible with T. pretiosum releases and should be preferred over the other active substances. Further studies with the harmful insecticides (thiodicarb, chlorfenapyr and methomyl) are required to determine their toxicity under field conditions and confirm their incompatibility with T. pretiosum releases.

Toxicity of insecticides to the egg parasitoids Telenomus podisi and Trissolcus teretis (Hymenoptera: Scelionidae)

ABSTRACT This work aims to evaluate the toxicity of insecticides used for stink bug control to the egg parasitoids Telenomus podisi and Trissolcus teretis. We tested ethiprole and sulfoxaflor + lambda-cyhalothrin in comparison with thiamethoxam + lambda-cyhalothrin and chlorpyrifos. Three independent bioassays were conducted in the laboratory and repeated for each parasitoid species, to evaluate the effect of insecticides on pupal and adult stages of the parasitoids and the effects of insecticide sprays on host eggs prior to parasitism. Ethiprole at concentrations of 100 and 133.3 g/100 L H2O was classified as harmless (class 1), according to the International Organization of Biological Control to both pupae and adults of T. podisi. When tested against T. teretis, ethiprole was classified as harmless (class 1) and slightly harmful (class 2), but it still was the most selective pesticide among the studied chemicals. When adult parasitoids of both species were exposed to sprayed host eggs, parasitism rates were similar. The other treatments triggered more severe negative side effects to the parasitoids, especially to adults. Overall, ethiprole was the least toxic compound among the studied products and should be preferred in integrated pest management aimed at preserving these biocontrol agents, while the other tested insecticides should be evaluated under semi-field and field conditions to verify their higher toxicity.

Survival, development and reproduction of Harmonia axyridis (Pallas, 1773) (Coleoptera: Coccinellidae) under effects of insecticides used in tomato plants.

Agriculture depends on the correct use of different methods for pest control, however the cultivation methods adopted for Solanaceae demands numerous pesticide applications. These products can be either harmful or selective to beneficial organisms, such as Coccinellidae predators. The aim of this study was to assess the physiological selectivity of insecticides, registered for tomato pest control, on Harmonia axyridis (Pallas, 1773) (Coleoptera: Coccinellidae). The maximum recommended field dosage of the insecticides spinetoram, spiromesifen, methoxyfenozide, metaflumizone, tebufenozide and methomyl was used. They were sprayed on eggs, third instar larvae, pupae and adults of H. axyridis using Potter´s tower; control treatment consisted of water. Methoxyfenozide didn't reduce any biological feature of the predator. Spiromesifen only reduced survival over time when sprayed on third instar larvae. Spinetoram shortened larval period and reduced survival of adults. When sprayed on larvae, metaflumizone reduced larval survival. Tebufenozide reduced egg viability, pupal period and larval survival over time. It is concluded that methoxyfenozide, spiromesifen and spinetoram are the least toxic to H. axyridis, and their usage should be prioritized in integrated pest management (IPM) programs; both tebufenozide and metaflumizone are harmful to some important biological features of the predator. Methomyl is highly toxic in controlled conditions, so its toxicity to H. axyridis should be confirmed in field and greenhouse tests, we also suggest further studies with the other compounds in different concentration and route of exposure.

Anatomy and histology of the alimentary canal of larvae and adults of Chrysoperla externa (Hagen, 1861) (Neuroptera: Chrysopidae).

The larvae of the lacewing Chrysoperla externa are important predators with the potential to be used in the biological control in agriculture. Although some studies provide important data on the gut morphology in lacewings, they are limited to few species. This study describes the anatomy and histology of the alimentary canal in the predatory larvae and herbivorous adult of C. externa. In larvae, the crop is the larger part of the foregut and it is connected to the midgut by the stomodeal valve. The midgut is an enlarged sac-like organ. At the mid-hindgut transition, there are eight Malpighian tubules. The hindgut is a non-functional vestigial region in the larvae. In adults, the crop has a diverticulum associated with large tracheal trunks, a conic proventriculus with sclerotized lips followed by an elongated tubular midgut. Histological analyses of larval and adult midgut show the presence of a single-layered epithelium with columnar cells with well-developed brush border, nests of regenerative cells, and a peritrophic matrix lining the midgut lumen. The hindgut in adults has an epithelium with cubic cells lined by a thin cuticular intima and rectal pads in the rectum. These data are discussed in comparison with the digestive tract in other Chrysopidae.

Morphology of the male and female reproductive tracts of virgin and mated Chrysoperla externa (Hagen, 1861) (Neuroptera: Chrysopidae).

Predatory insects have reproductive organs rich in complex changes that may be responsible for the success of their population growth. The species Chrysoperla externa is a predator used in biological control programs in Latin America. However, there is no morphological data about the morphology of the reproductive tract in this insect. This study describes the morphology of the reproductive organs of virgin and mated C. externa male and female. The male has a pair of testes yellow in color and five pairs of accessory glands closely associated with the seminal vesicles. The testis follicles are twisted filled with cysts in different developmental stages. The pair of ovaries in the females shows asymmetry with 9-11 ovarioles per ovary with oocytes in different developmental stages and a spherical spermatheca. Virgin and mated males have no differences in the size of the testes, seminal vesicle, and accessory glands. C. externa females show morphological changes in the reproductive tract according to sexual maturation, which is triggered by mating. The ovary activation occurs after female mating. The ovaries are of merotistic polytrophic type. The spermathecal reservoir is lined by a flattened epithelium with a thin cuticular intima and associated with well-developed muscles. It is concluded that the reproductive tract of C. externa is similar in virgin and mated males and females. Egg production is activated only after mating and the development of reproductive tract structures is faster in mated females.

Susceptibility of Chrysoperla externa (Hagen, 1861) (Neuroptera: Crysopidae) to insecticides used in coffee crops.

The coffee crop hosts pests such as mites, mealybugs, and aphids which serve as food for the predator Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae). The preservation of this chrysopid in coffee agroecosystem is very important to achieve sustainability of this agricultural sector, and can be obtained by applying low toxicity insecticides. The present study aimed to evaluate the susceptibility of C. externa to azadiracthin, chlorpyrifos, ethiprole and teflubenzuron. Predator eggs, third instar larvae, pupae and adults were exposed to insecticides by Potter tower spraying. When evaluating exposure of C. externa eggs we observed that chlorpyrifos, ethiprole and teflubenzuron reduced larvae hatching, while azadiracthin prolonged first instar duration. Meanwhile, the exposure of third instar larvae to chlorpyrifos and ethiprole caused mortality of all insects after 72 h, while azadiracthin prolonged the larval development time; we also observed that no compound allowed the formation of adults. After pupae were exposed to chlorpyrifos and teflubenzuron, it was observed a reduction on the emergence of adults, while the longevity of adults from these pupae and the evaluated reproductive parameters were reduced by all insecticides. For the bioassay with adults, chlorpyrifos, ethiprole and teflubenzuron reduced the longevity of insects, while the reproductive parameters evaluated were negatively affected after exposure to azadiracthin and teflubenzuron. It was concluded that all insecticides negatively affected at least one biological characteristic of the predator in at least one of the insect's developmental stages, requiring further research in semi-field and field conditions to prove its toxicity.

Biocontrol potential of methyl chavicol for managing Spodoptera frugiperda (Lepidoptera: Noctuidae), an important corn pest.

Synthetic insecticides applied to control Spodoptera frugiperda (Lepidoptera: Noctuidae) can have negative impacts on environment and human health. Botanical essential oils can be sources of organic molecules with biocontrol potential and advantages, such as minor impacts on the selection of resistant pest insects and low toxicity to humans. The aim of this study was to investigate the biocontrol action of essential oils from Brazilian species and methyl chavicol compounds on the development and metabolism of S. frugiperda. Essential oils of Eremanthus erythropappus (Asteraceae), Ocimum selloi, Hyptis suaveolens, and Hyptis marrubioides (Lamiaceae) were distilled by the steam distillation method and analyzed by gas chromatograph techniques. The essential oils were incorporated into an artificial diet (at 1, 2, and 4 mg mL-1) and offered to S. frugiperda caterpillars. Larvae of S. frugiperda at 48 h of age were fed an artificial diet containing the major constituent of O. selloi (methyl chavicol). The major compounds of the essential oils were methyl chavicol for O. selloi, α-bisabolol for E. erythropappus, bicyclogermacrene for H. suaveolens, and ß-thujone for H. marrubioides. O. selloi caused 100% mortality in S. frugiperda larvae at a concentration of 1 mg mL-1 after 48 h. H. marrubioides essential oil caused 100% mortality in larvae at a concentration of 4 mg mL-1 after 48 h. O. selloi and H. marrubioides inhibited acetylcholinesterase (AchE) activity in 72.87% and 81.69% of larvae, respectively. O. selloi presented the highest toxicity to S. frugiperda and the lowest inhibition of AchE. Methyl chavicol was lethal to all larvae within 24 h at a concentration of 0.92 mg mL-1 of diet. Methyl chavicol showed the best insecticidal activity and potential to be used as a natural insecticide to control S. frugiperda.

The Compared Efficiency of the Traditional Method, Radiography without Contrast and Radiography with Contrast in the Determination of Infestation by Weevil (Sitophilus zeamais) in Maize Seeds.

Technologies that increase safety and efficiency, while facilitating and streamlining the work of seed analysts, are increasingly required by the seed industry. X-ray image analysis is a technique that has been used in the analysis of grain and seeds because it is fast, accurate and non-destructive. The traditional method to verify the presence of insect damage in seeds involves manual cutting of the seeds, which endangers the safety of the analyst and is time-consuming and repetitive work that leads to visual fatigue. The objective of this study was to compared the efficiency of radiographic analysis with and without contrast in the determination of infestation by Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae), at different stages of development, in maize seeds, compared to the traditional method required by seed legislation, which consists of cutting and visual evaluation. Seeds were evaluated regarding the presence of eggs/oviposition signs, larvae, pupae, adult insects, insect damage in five infestation periods (5, 18, 33 and 35 days after infestation), while evaluating the total number of seeds infested, comparing the three methods. For characterization of the oviposition stage, the use of contrast was best at all times of infestation. For the larval stage, there was no difference between the evaluation methods; however, at 18 days, larger infestations were observed by the traditional method. At 5 days, the identification of pupae was better by the traditional method and radiography without contrast, while for the identification of adult insects the best method was the use of radiography without contrast. The characterization of the level of infestation with maize weevil damage was best verified using contrast radiography. Radiographic analysis is efficient in the detection of damage caused by S. zeamais in maize seeds. This method of radiographic analysis (with or without contrast) is thus an auxiliary tool to assess the damage and presence of S. zeamais in maize seeds.

Lethal and sublethal effects of insecticides on Engytatus varians (Heteroptera: Miridae), a predator of Tuta absoluta (Lepidoptera: Gelechiidae).

The mirid Engytatus varians (Distant) is a promising biological control agent of the tomato borer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), one of the most destructive pests of tomato (Solanum lycopersicum L.). The effects of five insecticides commonly used on tomato crops in Brazil were evaluated on E. varians in laboratory and semifield conditions. Glass Petri dish with residues of chlorfenapyr, thiamethoxam, and abamectin caused ˃90% mortality in both stages of the predator 72 h post-treatment, except imidacloprid that caused 78% of nymphs mortality. Teflubenzuron caused 24 and 66% mortality on adults and nymphs, respectively. The offspring of females derived from treated nymphs with teflubenzuron was significantly lower than the control but not when females were treated as adults. Longevity of males derived from nymphs treated with teflubenzuron was significantly reduced, but no effects were observed on females. When males and females were treated as adults with teflubenzuron there were no effects on their longevity. In the greenhouse-aged tomato plants, the 2 h-old residues of thiamethoxam, chlorfenapyr, and abamectin caused more than 70% of mortality of third instar of E. varians at 72 h post-treatment, 12 day-old residues of all three compounds caused a mortality lower than 30%. These data suggest that teflubenzuron can be associated with releases of E. varians adults, while the use of other evaluated pesticides should be avoided in this situation. Although, the low persistence of these products indicate that their spraying and later releases of E. varians adults on tomato crops are a possible strategy to control T. absoluta.

Pesticide selectivity to natural enemies: challenges and constraints for research and field recommendation / Seletividade de agrotóxicos nos inimigos naturais: desafios e restrições para a pesquisa e recomendações de campo

ABSTRACT: Pesticides are considered the first line of defense for the control of pests and diseases. At least in the short and medium term, the use of pesticides will remain an important strategy for pest management, allowing growers to produce crops of sufficient quality at low costs. A broad approach known as Integrated Pest Management (IPM) combines several different pest-control strategies, among which the combination of chemical and biological control stands out. It requires pesticides that achieve optimal control of target pests with minimal impact on the activity of biological control agents. Because of the dynamics of pest infestations, IPM routines are continuously adjusted by growers, requiring comprehensive information about pesticide effects on natural enemies. However, this information is not always available and often contradictory, which constrains the design of field recommendations. In this review, we focused on the importance of selective pesticides in IPM programs, and the effects of chemical pesticides on parasitoids, predators, and entomopathogenic fungi. We provided a detailed discussion of the challenges and constraints for research on pesticide effects on natural enemies, as well as for the resulting field recommendations.

RESUMO: Para o controle de pragas e doenças, os agrotóxicos são considerados a primeira linha de defesa. Pelo menos no curto e médio prazo, o seu uso continuará a ser uma estratégia importante de manejo, permitindo aos produtores produzir com baixo custo e boa qualidade. O manejo integrado de pragas (MIP) combina várias estratégias diferentes de controle de pragas. Entre elas, a associação do controle químico e biológico tem grande importância. Isto depende de agrotóxicos que tenham um ótimo controle das pragas alvo, com mínimo de impacto possível sobre a atividade dos agentes de controle biológico. Assim, devido à dinâmica de pragas, os produtores precisam de informações completas sobre os efeitos dos agrotóxicos sobre os inimigos naturais visando constantemente ajustar suas rotinas de MIP. No entanto, estas informações não estão sempre disponíveis, e quando encontradas, são muitas vezes contraditórias, o que prejudica as recomendações de campo. Nesta revisão, destacamos a importância de agrotóxicos seletivos em programas de MIP e seus efeitos sobre parasitoides, predadores e fungos entomopatogênicos. Ainda, discutiremos com mais detalhes os desafios e restrições para a pesquisa e recomendações de campo sobre seletividade de agrotóxicos.

Lethal and sublethal effects of pesticides on Chrysoperla carnea larvae (Neuroptera: Chrysopidae) and the influence of rainfastness in their degradation pattern over time.

The predator Chrysoperla carnea is a model species for the study of non-target effects of pesticides under different scenarios: registration of plant protection products under the European Union and effects of the Bt toxin. Laboratory and persistence studies were carried out with six pesticides currently used in corn crops in Spain that were applied at their maximum field recommended concentrations. The assessed end-points were larval mortality, survivorship until adult stage, duration of the larval and pupal periods, fecundity, fertility and sex ratio of the emerged adults. Based on the total effect (lethal and sublethal) caused to L3 larvae in contact with fresh residues in the laboratory, pendimethalin was harmless (IOBC 1), lambda-cyhalothrin, abamectin, and hexythiazox were slightly harmful (IOBC 2), deltamethrin was moderately harmful (IOBC 3) and chlorpyrifos was harmful (IOBC 4). Afterwards, the residues of the two most toxic pesticides in the lab (deltamethrin and chlorpyrifos) were aged under greenhouse conditions (22 ± 2 °C, 40 ± 10 % R.H., 16.9 µmol m(-2) s(-1) UV radiation) in the presence and absence of artificial rainfall (10 l m(-2) h(-1), applied 24 h after pesticide application). Deltamethrin was classified as short lived (IOBC A) in both cases. However, degradation of chlorpyrifos residues was accelerated in the presence of rainfall, leading to the classification as slightly persistent (IOBC B), while in absence of rainfall it behaved as persistent (IOBC D). Every pesticide can be recommended for inclusion in corn IPM programs where the predator is present except chlorpyrifos that exhibited high direct toxicity in the lab and prolonged residual action even in the presence of rainfall.

Sublethal effects of insecticide seed treatments on two nearctic lady beetles (Coleoptera: Coccinellidae).

Predatory insects often feed on plants or use plant products to supplement their diet, creating a potential route of exposure to systemic insecticides used as seed treatments. This study examined whether chlorantraniliprole or thiamethoxam might negatively impact Coleomegilla maculata and Hippodamia convergens when the beetles consumed the extrafloral nectar of sunflowers grown from treated seed. We reared both species on eggs of Ephestia kuehniella and then switched adult H. convergens to a diet of greenbugs, Schizaphis graminum, in order to induce oviposition in this species. Excised sunflower stems, either treated or control and refreshed every 48 h, were provided throughout larval development, or for the first week of adult life. Exposure of C. maculata larvae to chlorantraniliprole and thiamethoxam applied as seed treatments delayed adult emergence by prolonging the pupal period. When adults were exposed, thiamethoxam reduced the preoviposition period compared to chlorantraniliprole, whereas the latter treatment cause females to produce fewer clutches during the observation period. Larvae of C. maculata did not appear to obtain sufficient hydration from the sunflower stems and their subsequent fecundity and fertility were compromised in comparison to the adult exposure experiment where larvae received supplemental water during development. Exposure of H. convergens larvae to thiamethoxam skewed the sex ratio in favor of females; both materials reduced the egg viability of resulting adults and increased the period required for eclosion. Exposure of H. convergens adults to chlorantraniliprole reduced egg eclosion times compared to thiamethoxam and exposure to both insecticides reduced pupation times in progeny. The results indicate that both insecticides have negative, sublethal impacts on the biology of these predators when they feed on extrafloral nectar of sunflower plants grown from treated seed.

Espécies, número e frequência de visitantes florais em culturas agrícolas submetidas à aplicação de produtos fitossanitários / Species, number and frequency of floral visitors in crops submitted to the application of pesticides

Produtos fitossanitários podem influenciar de maneira negativa a atratividade ou o comportamento de visitantes florais. Dessa forma, o presente trabalho teve como objetivo avaliar a influência desses produtos na diversidade de espécies e frequência de visitação floral nas culturas do pimentão e do tomateiro após a aplicação de produtos fitossanitários. Os produtos aplicados foram ciantraniliprole, ciantraniliprole + tiametoxam, tiametoxam, imidacloprido, ciantraniliprole + abamectina e diafentiurom. Os ensaios foram realizados em campo no período de junho a novembro de 2012. Foram avaliados o número total de espécies e o número de visitas de visitantes florais no período de 26 de junho de 2012 a 11 de setembro de 2012 para a cultura do tomateiro e de 25 de setembro de 2012 a 13 de novembro de 2012 para a cultura do pimentão. Para o cultivo do tomateiro, foi encontrado um total de 8 espécies de visitantes florais; para a cultura do pimentão, foram verificadas 27 espécies. Os produtos fitossanitários aplicados tanto na cultura do tomateiro quanto na do pimentão não reduziram o número de visitantes florais nem a frequência de visitação dos insetos, demonstrando seletividade ecológica.(AU)

Pesticides can negatively influence on the attractiveness or behavior of floral visitors. Thus the present study aimed to evaluate the influence on species diversity and frequency floral visitation in chili and tomato crop after the application of pesticides. The products applied were ciantraniliprole, ciantraniliprole + thiamethoxam, thiamethoxam, imidacloprid, ciantraniliprole + abamectin and diafenthiuron. Assays were performed in the field during the period from June to November 2012. It was evaluated the total number of species and the number of visits of floral visitors in the period from 26/06/2012 to 11/09/2012 for the tomato crop and 25/09/2012 to 13/11/2012 for the chili crop. In the tomato crop was found a total of eight species of flower visitors, and to the chili crop was verified 27 species. The pesticides applied both in the tomato and chili crop did not reduce the number of floral visitors and the frequency of visitation of insects, showing ecological selectivity.(AU)

Sublethal and transgenerational effects of insecticides in developing Trichogramma galloi (Hymenoptera: Trichogrammatidae) : toxicity of insecticides to Trichogramma galloi.

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.

Seletividade de inseticidas utilizados na cana-de-açúcar a adultos de Trichogramma galloi zucchi (Hymenoptera: Trichogrammatidae) / Selectivity of inseticides used in the sugar-cane on adults of Trichogramma galloi zucchi (Hymenoptera: Trichogrammatidae)

Diatraea saccharalis (Fabricius) é uma das principais pragas da cultura da cana-de-açúcar e tem como importante inimigo natural o parasitoide de ovos Trichogramma galloi (Zucchi). Durante o manejo da cultura são utilizados produtos que podem afetar o desempenho do parasitoide, portanto, é necessário que estes produtos sejam seletivos. Sendo assim, este trabalho objetivou avaliar os efeitos de inseticidas utilizados na cana-de-açúcar sobre adultos de T. galloi. Foram testados os inseticidas clorantraniliprole, etiprole, tiametoxam, triflumurom, lambdacialotrina+ tiametoxam, fipronil e Metarhizium anisopliae (Metsch.), nas maiores concentrações indicadas à cultura da cana. Fêmeas de T. galloi, com até 24h receberam ovos de D. saccharalis que foram imersos nas caldas químicas de cada produto. Foram avaliados a mortalidade e o número de ovos parasitados pela geração F0 de T. galloi; e a emergência da geração F1. Clorantraniliprole, M. anisopliae e triflumurom, foram classificados como inócuos (classe 1) em relação à sobrevivência de adultos de T. galloi. Já para o parasitismo, esses inseticidas foram inócuos ou levemente prejudiciais ao parasitoide. Quanto à emergência de T. galloi, clorantraniliprole e M. anisopliae foram inócuos e triflumurom, moderadamente prejudicial. Os demais produtos avaliados foram prejudiciais à sobrevivência de T. galloi e não foram inócuos ao parasitismo e emergência desse parasitoide. Nesse sentido, clorantraniliprole e M. anisopliae foram seletivos (inócuos ou levemente prejudiciais) em todos os parâmetros avaliados para T. galloi e podem ser recomendados para um programa de manejo, para controle de D. saccharalis.

Diatraea saccharalis (Fabricius) is one the most important pest of sugarcane crops and Trichogramma galloi (Zucchi) an egg parasitoid, is considered an important natural enemy. During the management of this crop some products can affect the performance of this parasitoid, being necessary to found selective products. For this reason, the aim of this study was to evaluate the effects of some insecticides used in sugarcane crop on adults of T. galloi. The products tested were chlorantraniliprole, ethiprole, thiametoxan, triflumuron, lambda-cialotrina+thiametoxan, fipronil and Metarhizium anisopliae (Metsch.), in the highest dosages recommended by sugarcane. Females of T. galloi, with 24h, received eggs from D. saccharalis that were immersed in the solutions of each product. It were evaluated the mortality and the number of parasitized eggs of F0 generations of T. galloi; and the emergence of F1. Chlorantraniliprole, M. anisopliae, triflumuron, were classified was harmless (class 1) for mortality of T. galloi and for parasitism, these insecticides were harmless or slightly harmful. About the emergence, chlorantraniliprole and M. anisopliae were harmful and triflumuron, moderately harmful. The other products were harmful to survival of T. galloi and were not harmless to parasitism and emergence this parasitoid. In this sense, chlorantraniliprole and M. anisopliae were classified as a selective (harmless or slightly harmful) for all the parameters evaluated for T. galloi and could be recommended to management program to control D. saccharalis.