Temperature Impact on Telenomus podisi Emergence in Field Releases of Unprotected and Encapsulated Parasitoid Pupae.

This work aimed to evaluate the influence of temperature on the emergence of Telenomus podisi throughout the soybean development cycle, using encapsulated and unprotected pupae releases, in four different possible locations where pupae can be deposited during release. The trial was carried out in a randomized block design in a 2 × 4 factorial scheme: two parasitoid pupae release strategies (encapsulated and unprotected) × four pupae locations (between soybean lines of planting, bottom third, middle third, or upper third of plant canopy) with 5 replicates. There were no significant interactions between the studied factors. In the vegetative stage (V2 and V9), a smaller percentage of emergence of parasitoid adults was observed between soybean lines of planting (37.1% and 23.4% for V2 and V9 , respectively). The highest maximum temperatures were recorded between the soybean lines, with the greatest variations in maximum and minimum temperatures (55.2°C and 21.3°C) in V2 and (52.8°C and 23.9°C) in V9. In the reproductive stages (R1, R4, and R7), the observed temperatures were lower when compared to those observed in the vegetative stages (V2 and V9), with no difference in the emergence of parasitoid adults, which was above 70% in stage R1 and above 80% in R4 and R7. Regarding the pupae (encapsulated or unprotected), both allowed similar adult emergence. Therefore, it can be concluded that both unprotected and encapsulated pupae can be released, but those releases during the soybean vegetative development stage should be avoided due to the high temperatures to which pupae can be exposed.

Intrinsic Interspecific Competition Between Telenomus podisi and Trissolcus teretis (Hymenoptera: Scelionidae).

The competition between Telenomus podisi Ashmead and Trissolcus teretis (Johnson) parasitizing eggs of Diceraeus melacanthus (Dallas) and Euschistus heros (Fabricius) was studied in three different laboratory bioassays to gather knowledge in order to improve stink bug management and to strengthen the preservation of naturally occurring parasitoid species. The impact of parasitoid sequence and time intervals (4 to 192 h) between parasitoid species was evaluated. Competition of Te. podisi and Tr. teretis for the same host favored the parasitoid encountering the egg host first, as it usually outcompetes the second parasitoid. We conclude that it is unwarranted in a short-term goal to release both species together in augmentative biological control programs since the repeated release of Te. podisi led to higher parasitism than any other studied variation of parasitoid sequence. However, simultaneous release of multiple species could be important to help the preservation of the diversity of scelionids in the agroecosystem, a hypothesis that needs to be further investigated in future research.

Biological characteristics of Trissolcus urichi (Crawford) (Hymenoptera: Scelionidae) on Euschistus heros (Fabricius) and Dichelops melacanthus (Dallas) (Hemiptera: Pentatomidae) Eggs.

Species of the genus Trissolcus are effective as egg parasitoids of Euschistus heros and can potentially be used in a multispecies pest management approach. However, in order to successfully use those biocontrol agents in the field, previous detailed knowledge about their life history are necessary. Therefore, we evaluate some biological characteristics of Trissolcus urichi on Euschistus heros and Dichelops melacanthus eggs. Three independent experiments were performed: (1) T. urichi host preference between E. heros and D. melacanthus eggs. (2) T. urichi eggs-adult period (days), number of parasitized eggs in 24 h, emergence rate (%) and sex ratio of the parasitoid in E. heros and D. melacanthus eggs. (3) Morphometric characteristics of T. urichi grown on E. heros and D. melacanthus eggs. Trissolcus urichi preferred to parasitize E. heros eggs, exhibiting a higher number of parasitized eggs, higher rate of emergence (%) and faster development, as well as producing progeny of larger size than the parasitoids emerged from eggs of D. melacanthus in relation to body length, wing length and width. Thus, it can be concluded that T. urichi had better performance on E. heros eggs, although the parasitoid had also acceptable parasitism capacity and development in D. melacanthus eggs.

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.

Diceraeus melacanthus (Dallas) (Hemiptera: Pentatomidae) development, preference for feeding and oviposition related to different food sources

ABSTRACT The dispersion of Diceraeus melacanthus (Dallas) from soybean (first crop season) to maize (second crop season) is facilitated by the presence of weeds (e.g. Commelina benghalensis) and soybean grains on the ground. Understanding insect development and behavior on different food sources is important to develop pest management strategies. Thus, three independent experiments were conducted to study D. melacanthus nymph development, and adult preference for feeding and oviposition in different food source scenarios in the field. The first two trials studied development and food preference of D. melacanthus related to different food sources (C. benghalensis branches, moistened soybean grain + soybean seedlings, maize seedlings + C. benghalensis branches, moistened soybean grains + maize seedlings, moistened soybean grains + C. benghalensis branches, maize seedlings, as well as a standard diet). The third trial evaluated D. melacanthus oviposition preferences between the aforementioned plants. Overall, moistened soybean grains resulted in better nutritional quality, thus being crucial for D. melacanthus development, triggering faster nymph development as well as better overall adult fitness. The combination of soybean grains and maize seedlings or C. benghalensis branches showed great potential to benefit D. melacanthus, since these complementary food sources improved stink bug fitness, increasing mainly adult longevity, fecundity and egg viability. Therefore, it can be concluded that in order to reduce D. melacanthus outbreaks in second season maize, it is important to reduce soybean harvest loss (reducing, therefore, moistened soybean grain on the ground) and eliminate stink bug associated plants like C. benghalensis.

Mixture compatibility of Anticarsia gemmatalis nucleopolyhedrovirus (AgMNPV) with pesticides used in soybean / Compatibilidade da mistura de nucleopoliedrovírus de Anticarsia gemmatalis baculovírus (AgMNPV) com agrotóxicos utilizados na soja

Anticarsia gemmatalis (Hübner: 1818) (Lepidoptera: Erebidae) is one of the main pests that affect soybean crops, causing defoliation. In the vegetative stages, defoliation occurs together with weeds, and in the reproductive stages with pathogens. In this sense, to maintain plant health, it is necessary to carry out the combined use of pesticides. Thus, this research determined the compatibility of the entomopathogenic virus AgMNPV with the main herbicides and fungicides used in soy at different times of the mixture. The artificial diet was immersed in the solutions of the pesticides and their mixtures and supplied to A. gemmatalis caterpillars, immediately and after one and two hours of mixing. The evaluation was performed by quantifying the number of dead caterpillars by mixing the AgMNPV virus with herbicides and fungicides, even after two hours of mixing if compatible. The observed scenarios showed a compatibility of the virus with the herbicides and fungicides, with mortality rates between 70 to 99% for A. gemmatalis.

Anticarsia gemmatalis (Hübner: 1818) (Lepidoptera: Erebidae) é uma das principais pragas que acometem a cultura da soja, causando desfolha. Nos estágios vegetativos a desfolha ocorre juntamente com ervas daninhas, e no reprodutivo com patógenos. Nesse sentido, para manter a fitossanidade, é necessário realizar a utilização combinada de pesticidas. Assim, o objetivo do presente trabalho foi determinar a compatibilidade do vírus entomopatogênico AgMNPV com os principais herbicidas e fungicidas utilizados na soja em diferentes tempos de mistura. A dieta artificial foi imersa nas soluções dos pesticidas e suas misturas e fornecida às lagartas de A. gemmatalis, imediatamente e após uma e duas horas de mistura. A avaliação foi realizada quantificando o número de lagartas mortas. A mistura do vírus AgMNPV com herbicidas e fungicidas, mesmo após duas horas de mistura se mostrou compatível. Os cenários observados mostram a compatibilidade do vírus com os herbicidas e fungicidas, com percentuais de mortalidade entre 70 a 99% para A. gemmatalis.

Trissolcus teretis (Johnson, 1987) (Hymenoptera: Scelionidae) parasitism on Euschistus heros (Fabricius, 1798) and Diceraeus melacanthus Dallas, 1851 (Hemiptera: Pentatomidae) eggs at different temperatures

ABSTRACT Trissolcus teretis has been recorded to parasitize eggs not only of Euschistus heros and Diceraeus melacanthus but also of other stink bug species in the most important soybean producing countries of South America such as Brazil, Argentina as well as other countries of the Neotropical region. Despite several studies relating to its natural incidence and parasitism, the impact of different temperatures on biology and parasitism capacity of T. teretis on eggs of E. heros and D. melacanthus is practically unknown. Considering that biological traits can be highly influenced by temperature, research on T. teretis parasitism at different temperatures and hosts is of theoretical and practical interest. We therefore evaluated T. teretis parasitism and development on eggs of E. heros and D. melacanthus at 15ºC, 20ºC, 25ºC, and 30ºC. Temperature had an impact on the parasitoid reared on eggs of both studied hosts. Although we recorded parasitism at an extreme temperature of 15ºC, these conditions are unfavorable for T. teretis parasitism, impairing parasitoid biological traits, especially survival of larvae and adult parasitism. Therefore, for application in crop fields where temperatures of 15ºC or lower are common, additional studies are necessary to investigate the possible need to increase parasitoid numbers during releases or to choose smaller intervals between multiple releases.

Effects of parasitoid and host age on the parasitism of Trichogramma pretiosum on eggs of Anticarsia gemmatalis

Abstract The ages of parasitoid females and their hosts can have substantial effects on parasitism and parasitoid efficacy. This relationship has been investigated over the last few decades and found to vary among species. To our knowledge, it was virtually unknown for Trichogramma pretiosum wasps that parasitize Anticarsia gemmatalis eggs. Therefore, the influence of parasitoid and host age on the parasitism of T. pretiosum on eggs of A. gemmatalis was here evaluated in three independent bioassays. Neither the number of parasitized eggs nor that of emerged parasitoids differed between T. pretiosum females of different age. The number of parasitoids per egg and the sex ratio were higher for 5-day-old females. Regarding host age, the number of parasitized eggs was highest for A. gemmatalis eggs aged 24 h (9.60), followed by eggs aged 48 h (1.00), while no parasitism was observed for eggs aged 72 h. The number of parasitoids per egg and sex ratio were not influenced by host age. Preference was significantly higher for host eggs aged 24 h (79.67%), followed by eggs aged 48 h (16.99%) and 72 h (3.33%). Accordingly to these results, the key challenge for a successful T. pretiosum release to control A. gemmatalis in the field is to synchronize the presence of up to 5-day-old adults with the most susceptible phase of the host eggs (1 day).

Selectivity of different biological products to the egg parasitoid Telenomus remus (Hymenoptera: Platygastridae)

ABSTRACT The selectivity of five entomopathogens and a chemical insecticide (positive control) to pupae and adults of the egg parasitoid Telenomus remus (Nixon) was evaluated in the laboratory under controlled environmental conditions according to protocols established by the International Organization for Biological Control. Baculovirus anticarsia (Baculovirus AEE®), Bacillus thuringiensis var. kurstaki (Thuricide®), Bacillus thuringiensis var. aizawai (Agree®), Beauveria bassiana (Boveril®), Metarhizium anisopliae (Metarril®) and Trichoderma harzianum (Trichodermil®) are harmless to T. remus pupae, and adults. Thus, our results suggest that the insect control strategies applied here are compatible since entomopathogens were classified as harmless to T. remus in most examined cases and therefore facilitate a joint application to control different pests. Bacillus thuringiensis var. kurstaki (Dipel®), despite being classified as slightly harmful in some of the evaluations, can still be considered compatible for use together with T. remus, especially when compared with chemical insecticides such as chlorpyrifos that might be considered harmful to the parasitoid survival.

Influence of host preference, mating, and release density on the parasitism of Telenomus remus (Nixon) (Hymenoptera, Platygastridae)

ABSTRACT We evaluated the influence of host preference, mating, and release density on Telenomus remus (Nixon, 1937) (Hymenoptera: Platygastridae) parasitizing eggs of Spodoptera frugiperda (Smith, 1797) (Lepidoptera: Noctuidae). First, we tested host preference of T. remus (free choice test) offered a choice between eggs of Corcyra cephalonica (Stainton, 1865) (Lepidoptera: Pyralidae) and S. frugiperda. Parasitism capacity and host preference (S. frugiperda) of T. remus reared on either of the two hosts did not differ. Secondly, we evaluated the influence of mating behavior of T. remus females on its parasitism. Only the offspring sex ratio differed between treatments, indicating that the species reproduces by parthenogenesis of the arrhenotoky type. Finally, we evaluated the influence of release density on T. remus parasitism. This was tested by releasing different numbers of the parasitoid per S. frugiperda egg using T. remus reared for different numbers of generations on C. cephalonica eggs. The regression analysis between percentage of parasitism and density of released T. remus females showed a quadratic effect for all tested parasitoid generations (F35, F40, and F45) with maximum parasitism from 65.07% to 71.69%. Our results allow the conclusion that (a) T. remus prefers S. frugiperda eggs, regardless of the host on which this parasitoid was reared, showing no preimaginal conditioning; (b) Mating does not affect the number of eggs parasitized by T. remus or the development of its offspring; and (c) The optimal T. remus release density when reared on C. cephalonica is between 0.133 and 0.150 females/S. frugiperda.

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.

Size and flight ability of Telenomus remus parasitoids reared on eggs of the factitious host Corcyra cephalonica

ABSTRACT In two independent bioassays, size and flight ability of parasitoids reared on eggs of Corcyra cephalonica for 19 generations and parasitoids reared on a natural host (Spodoptera frugiperda eggs) for 250 generations were compared as fast quality control procedures for insect rearing. The size of parasitoids was examined by morphometric analysis using a stereoscope. Length and width of the wings, right hind tibia, and the body of 20 individuals (males and females) were measured. In the analysis of flight ability, parasitoids were divided into three groups: individuals able to fly ("flyers"), individuals that did not fly but had no visible deformation ("walkers"), and individuals with visible deformation ("deformed"). We observed that parasitoids were larger when reared on the natural host than on the factitious host for all evaluated morphological characters. However, there was no significant difference between the treatments regarding the number of "flyers", "walkers" or "deformed" parasitoids. This indicates that even though the rearing of T. remus on a factitious host affects parasitoid size, it does not necessarily affect its flight ability and therefore suggests that C. cephalonica is suitable as a factitious host for mass rearing of T. remus. Other biological parameters still need to be evaluated, such as host finding ability, parasitism capacity, and parasitoid field efficacy in order to provide a more complete picture of the effects caused by a host change. However, because fast laboratory tests are needed in rearing facilities, the one used in this study might be useful to rapidly assess parasitoid quality.

Lepidopteran larva consumption of soybean foliage: basis for developing multiple-species economic thresholds for pest management decisions.

BACKGROUND: Defoliation by Anticarsia gemmatalis (Hübner), Pseudoplusia includens (Walker), Spodoptera eridania (Cramer), S. cosmioides (Walker) and S. frugiperda (JE Smith) (Lepidoptera: Noctuidae) was evaluated in four soybean genotypes. A multiple-species economic threshold (ET), based upon the species' feeding capacity, is proposed with the aim of improving growers' management decisions on when to initiate control measures for the species complex. RESULTS: Consumption by A. gemmatalis, S. cosmioides or S. eridania on different genotypes was similar. The highest consumption of P. includens was 92.7 cm(2) on Codetec 219RR; that of S. frugiperda was 118 cm(2) on Codetec 219RR and 115.1 cm(2) on MSoy 8787RR. The insect injury equivalent for S. cosmoides, calculated on the basis of insect consumption, was double the standard consumption by A. gemmatalis, and statistically different from the other species tested, which were similar to each other. CONCLUSIONS: As S. cosmioides always defoliated nearly twice the leaf area of the other species, the injury equivalent would be 2 for this lepidopteran species and 1 for the other species. The recommended multiple-species ET to trigger the beginning of insect control would then be 20 insect equivalents per linear metre.

Larval development of Spodoptera eridania and Spodoptera frugiperda fed on fresh ear of field corn expressing the Bt proteins (Cry1F and Cry1F + Cry1A.105 + Cry2Ab2) / Desenvolvimento larval de Spodoptera eridania e Spodoptera frugiperda alimentadas com espigas de milho verde expressando proteínas Bt (Cry1F e Cry1F + Cry1A.105 + Cry2Ab2)

ABSTRACT: The objective of this study was to evaluate extent of larval period, larval survival (%), food consumption, and pupal biomass of Spodoptera eridania and Spodoptera frugiperda (Lepidoptera: Noctuidae ) fed on fresh ears of field corn expressing Bt proteins (Cry1F and Cry1F+Cry1A.105+Cry2Ab2). Larvae of Spodoptera spp. survived less than two days when they consumed Bt corncobs and showed 100% mortality. Spodoptera eridania reared on non-Bt corn cobs showed higher larval development (21.6 days) than S. frugiperda (18.4 days) and lower viability (56.4% and 80.2% for S. eridania and S. frugiperda , respectively). A higher amount of corn grains was consumed by S. eridania (5.4g) than by S. frugiperda (3.9g). In summary, this study demonstrated that the toxins Cry1F and Cry1F + Cry1A.105 + Cry2Ab2 expressed in fresh corn cobs contributed to protect ears of corn against S. frugiperda and the non-target pest S. eridania . However, itis important to monitor non-Bt cornfields because of the potential of both species to cause damage to ear sof corn.

RESUMO: Este estudo teve como objetivo avaliar o período de desenvolvimento larval, sobrevivência larval (%), consumo de alimento e biomassa pupalde Spodoptera eridania e Spodoptera frugiperda (Lepidoptera: Noctuidae ), alimentadas com grãos verdes de milho Bt que expressam as proteínas Cry1F e Cry1F + Cry1A.105 + Cry2Ab2). As larvas de Spodoptera spp. alimentadas com milho Bt sobreviveram por até dois dias, registrando-se 100% de mortalidade. A espécie S. eridania alimentada com grãos de milho não Bt apresentou um maior desenvolvimento larval (21,6 dias) do que S. frugiperda (18,4 dias), e menor viabilidade larval (56,4% e 80,2% para S. eridania e S. frugiperda respectivamente). Uma maior taxa de consumo de grãos foi observada para S. eridania (5,4g) do que para S. frugiperda (3,9g). Em síntese, este estudo comprova que as toxinas Cry1F e Cry1F + Cry1A.105 Cry2Ab2 expressas em grãos imaturos de milho contribuem na proteção das espigas de milho contra S. frugiperda e a praga não-alvo S. eridania , entretanto, é importante monitorar as lavouras cultivadas com milho não Bt, devido o potencial de ambas as espécies em ocasionar danos nas espigas da planta.

Aspectos biológicos de Dichelops melacanthus em três temperaturas, alimentados com grãos imaturos de milho 2B688Hx e 2B688 / Biological aspects of Dichelops melacanthus at three temperature, reared on immature 2B688Hx and 2B688 corn grains

RESUMO: Este estudo investigou os aspectos biológicos de Dichelops melacanthus (Hemiptera: Pentatomidae) em três temperaturas (19±1°C, 25±1°C e 31±1°C), alimentados com grãos imaturos de milho 2B688Hx (expressa a proteína inseticida Cry1F, para o controle de lepidópteros-alvo) e 2B688. Foi observado que a temperatura de 19±1°C prejudicou o desenvolvimento de D. melacanthus, pois, nessa condição, foi registrada a maior taxa de mortalidade das ninfas, menor peso de adultos e as fêmeas não ovipositaram. Por outro lado, a duração da fase jovem, mortalidade, peso de adultos, fecundidade e viabilidade de ovos não diferiu entre as temperaturas 25±1°C e 31±1°C. Também foi demonstrado que os aspectos biológicos dos percevejos alimentados com grãos imaturos de milho 2B688Hx não diferiram dos que se desenvolveram com a isolinha 2B688. Este estudo comprova que D. melacanthus desenvolve-se melhor em condições de temperaturas mais elevadas (até 31±1°C), e o fato de se alimentar com grãos imaturos de milho 2B688Hx não afeta o seu desenvolvimento.

ABSTRACT: This study investigated the development of Dichelops melacanthus (Hemiptera: Pentatomidae) at different temperatures (19±1°C, 25±1°C and 31±1°C) reared on 2B688Hx (expressing Cry1F insectice protein to control lepidopterans target) immature corn grains. The temperature of 19±1°C impaired the development of D. melacanthus and recorded the highest mortality of nymphs, lower weight and adult females laid no eggs. Moreover, the length of the nymphal biology, adult weight, fecundity and viability of eggs did not differ between temperatures 25±1°C and 31±1°C. It was also shown that the biological aspects of green belly stink bugs fed with 2B688Hx immature grains of corn do not differ from that develop with 2B688 isoline. This study showed that the biological cycle of D. melacanthus is favored at warmer temperature (until 31±1°C), and the consume of immature corn grain 2B688Hx does not affect its development.

Organic products selectivity for Trichogramma pretiosum (Hymenoptera: Trichogrammatidae) / Seletividade de produtos orgânicos para Trichogramma pretiosum (Hymenoptera: Trichogrammatidae)

The selectivity of different insecticides, fungicides and fertilizers used in organic soybean cropping was evaluated according to the protocols proposed by the Pesticides and Beneficial Organisms Working Group of the International Organization for Biological Control (IOBC) concerning adults and pupae of the egg parasitoid Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) under laboratory conditions. Treatments 1) baculovirus anticarsia 140 x 109 cpi; 2) Bacillus thuringiensis 16.8 g; 3) azadirachtin-A, azadirachtin-B, nimbina and salamina 9.6 ppm; 4) rotenoids 4% 4 L; 5) nitrogen 1.3%, phosphorus 3.0% and total organic carbon 8.0% 3 L; 6) sodium silicate 2% 4 L; 7) copper 7% + calcium 3.3% 1.8 L; 8) sulfur 20% + quicklime 10% 1.8 L were in general safe (class 1) to both adults and pupae of T. pretiosum . Differently, chlorpyrifos (control treatment) was harmful to this parasitoid. Therefore, the utilization of the tested natural derived products in the production of organic soybean is viable, without impairing the natural biological control allowed by T. pretiosum . Furthermore, both management techniques can indeed be used together in organic cropping aiming at reaching increasing or complementary control of target pests. Chlorpyrifos use, on the other hand, whenever possible, should be replaced by other products more compatible with biological control preservation.(AU)

A seletividade de diferentes inseticidas, fungicidas e fertilizantes usados no cultivo de soja orgânica foi avaliada de acordo com os protocolos propostos pela Pesticide and Beneficial Organisms Working Group of the International Organization for Biological Control (IOBC) sobre pupas e adultos de Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) em condições de laboratório. Os tratamentos 1) baculovírus anticarsia 140 x 109 cpi; 2) Bacillus thuringiensis 16,8 g; 3) azadirachtin-A, azadirachtin-B, nimbina e salamina 9,6 ppm; 4) rotenoides 4% 4 L; 5) nitrogênio 1,3%, fósforo 3,0% e carbono orgânico total 8,0% 3 L; 6) silicato de sódio 2% 4 L; 7) cobre 7% + cálcio 3,3% 1,8 L; 8) enxofre 20% + cal virgem 10% 1,8 L foram, no geral, inócuos (classe 1) para pupas e adultos de T. pretiosum . Diferentemente, clorpirifós (tratamento controle) foi nocivo para esse parasitoide. A utilização dos produtos de origem natural avaliados é viável na sojicultura orgânica sem impactar o controle biológico promovido por T. pretiosum . Ambas as táticas de manejo podem ser utilizadas conjuntamente na agricultura orgânica objetivando aumentar ou complementar o controle da praga-alvo. O uso do clorpirifós, por outro lado, sempre que possível, deve ser substituído por outros produtos mais compatíveis com a preservação do controle biológico.(AU)

Larval development of Spodoptera eridania (Cramer) fed on leaves of Bt maize expressing Cry1F and Cry1F + Cry1A.105 + Cry2Ab2 proteins and its non-Bt isoline

This study aimed to evaluate, in controlled laboratory conditions (temperature of 25±2 °C, relative humidity of 60±10%, and 14/10 h L/D photoperiod), the larval development of Spodoptera eridania (Cramer, 1784) (Lepidoptera, Noctuidae) fed with leaves of Bt maize expressing Cry1F and Cry1F + Cry1A.105 + Cry2Ab2 insecticide proteins and its non-Bt isoline. Maize leaves triggered 100% of mortality on S. eridania larvae independently of being Bt or non-Bt plants. However, it was observed that in overall Bt maize (expressing a single or pyramided protein) slightly affects the larval development of S. eridania, even under reduced leaf consumption. Therefore, these results showed that Cry1F and Cry1F + Cry1A.105 + Cry2Ab2 can affect the larval development of S. eridania, although it is not a target pest of this plant; however, more research is needed to better understand this evidence. Finally, this study confirms that non-Bt maize leaves are unsuitable food source to S. eridania larvae, suggesting that they are not a potential pest in maize fields.

Toxicity of organic supplies for the egg parasitoid Telenomus podisi / Toxicidade de insumos orgânicos ao parasitoide de ovos Telenomus podisi

Toxicity (dosage per hectare) of: 1) Baculovirus anticarsia 140x109 cpi; 2) Bacillus thuringiensis 16.8g; 3) Azadirachtin-A, azadirachtin-B, nimbina and salamina 9.6 ppm; 4) Rotenoids 4 liters; 5) Nitrogen 1.3%, phosphorus 3.0% and total organic carbon 8.0% 3 liters; 6) Sodium silicate 2% 4 liters; 7) Copper 7% + calcium 3.3% 1.8 liters; 8) Sulfur 20% + quicklime 10% 1.8 liters; 9) Chlorpyrifos 384g; 10) Distilled H2O (control) were evaluated for pupae and adults of Telenomus podisi. Treatments from 1 to 8 were in general harmless (class 1) to both pupae and adults of T. podisi. Among them, only treatment 5 and 7 presented slightly toxic to the parasitoid with a reduction in parasitism 5 days after F1 parasitoid emergence. Differently, the chlorpyrifos was classified as slightly harmful (class 2) or moderately harmful (class 3). Therefore, the use of the tested organic agricultural supplies in the production of organic soybean is viable, without impairing the natural biological control allowed by this egg parasitoid. Chlorpyrifos use, on the other hand, is not allowed in organic soybean, but even on convention crop production, could whenever possible, be replaced by other products more compatible with T. podisi preservation.

A toxicidade (dosagem por hectare) de: 1) Baculovírus anticarsia 140x109cpi; 2) Bacillus thuringiensis 16,8g; 3) Azadirachtin-A, azadirachtin-B, nimbina e salamina 9,6ppm; 4) Rotenoides 4% 4 litros; 5) Nitrogênio 1,3%, fósforo 3,0% e carbono orgânico total 8,0% 3 litros; 6) Silicato de Sódio 2% 4 litros; 7) Cobre 7% + Cálcio 3,3% 1,8 litros; 8) Enxofre 20%, cal virgem 10% 1,8 litros; 9) Clorpirifós 384g; 10) Água destilada (controle) foi avaliada para pupas e adultos de Telenomus podisi. Os tratamentos do 1 ao 8 foram, em geral, inócuos (classe 1) para pupas e adultos de T. podisi. Entre eles, apenas os tratamentos 5 e 7 apresentaram toxicidade sobre o parasitoide, reduzindo o parasitismo 5 dias após a emergência da geração F1. Diferentemente, clorpirifós foi classificado como levemente nocivo (classe 2) e moderadamente nocivo (classe 3). Portanto, o uso dos insumos orgânicos avaliados é viável na produção da soja orgânica sem prejudicar o controle biológico natural deste parasitoide de ovos. O clorpirifós, entretanto, não é permitido na agricultura orgânica. Mesmo na agricultura convencional, sempre que possível, seu uso pode ser evitado, substituindo-o por outros produtos mais compatíveis com a preservação de T. podisi.

Persistência do baculovírus anticarsia após diferentes regimes pluviométricos / Velvet-bean nucleopolyhedrovirus persistence after different rainfall intensities

A persistência do vírus da lagarta-da-soja AgMNPV, produzido de forma bruta (maceração de lagartas) e liofilizada (produto comercial), foi avaliada após a aplicação em plantas de soja seguida de diferentes regimes pluviométricos (0; 10; 20; 30mm) na intensidade de 30mm.hora-1. Essas precipitações foram simuladas com microaspersores, em casa-de-vegetação. Após a simulação, a soja foi oferecida às lagartas zero, três, seis e nove dias após a aplicação (DAP). As plantas, durante esse período, foram mantidas em casa-de-vegetação, protegidas da chuva. O experimento foi conduzido em delineamento inteiramente casualizado em condições controladas (UR 70±10%, 25±2°C, fotofase de 14h), em esquema fatorial 4 (intensidades de precipitações pluviométricas) x 2 (formulações de vírus, bruta e liofilizada) com quatro repetições, com 30 lagartas cada. Os resultados comprovam que precipitações até 30mm, em 60 minutos, não reduzem a mortalidade das lagartas, causada por AgMNPV em ambas as formas de produção, quando a oferta das folhas às lagartas ocorre no mesmo dia da aplicação. As formas de preparo do AgMNPV influenciaram na persistência do vírus aos seis DAP. Nesta avaliação, a taxa de mortalidade foi superior a 90%, quando o produto bruto foi aplicado e inferior a 50% para o produto liofilizado. Esses resultados indicam que a eficiência de AgMNPV não é afetada por chuvas de até 30mm em uma hora, para ambas as formas de preparo do AgMNPV. Entretanto, ao longo dos dias, o método de preparo bruto apresenta-se mais eficiente, devido à maior persistência sobre a área foliar da soja após a lavagem pela água.

The persistence of the velvet-bean nucleopolyhedrovirus (AgMNPV) produced raw (macerated caterpillars) and lyophilized (commercial product) was evaluated after spraying in soybean plants followed by different simulated rainfall rates (0; 10; 20; 30mm) at 30mm hour-1 rate. Rainfall was simulated in greenhouse through micro sprinkler irrigation. After simulated rainfall, soybean leaves were offered to caterpillar in laboratory conditions at zero, three, six and nine days after spraying (DAS). Soybean plants were kept in greenhouse protected from rainfall. Trial was carried out in complete randomized design, under controlled conditions (RH 70%±10%, 25±2°C, 14h photophase) in a factorial 4 (rainfall rates) x2 (formulations, raw and lyophilized) with four replicates of 30 caterpillars. Results indicate that rainfall rates up to 30mm, in 60 minutes, do not decrease caterpillar mortality caused by AgMNPV regarding to both tested baculovirus formulations, raw and lyophilized virus, when leaves were offered to caterpillars at zero DAS. However, virus production (raw or lyophilized) impacted its persistence. Six DAS, mortality rate was higher than 90% when the virus was applied raw and lower than 50% when it was applied lyophilized. These results suggest that both raw and lyophilized AgMNPV efficacy is not impaired by 30-mm rainfalls at 30mm hour-1 rate. However, raw virus was more efficient in a long term evaluation since it had longer persistence on soybean leaves after being water washed.

No impact of Bt soybean that express Cry1Ac protein on biological traits of Euschistus heros (Hemiptera, Pentatomidae) and its egg parasitoid Telenomus podisi (Hymenoptera, Platygastridae)

No impact of Bt soybean that express Cry1Ac protein on biological traits of Euschistus heros (Hemiptera, Pentatomidae) and its egg parasitoid Telenomus podisi (Hymenoptera, Platygastridae). Biological traits of the stink bug Euschistus heros and its main biological control agent Telenomus podisi were evaluated under controlled environmental conditions (25 ± 2ºC; 60 ± 10% RH; and 14/10 h photoperiod) by placing first instar nymphs into Petri dishes with pods originating from two soybean isolines (Bt-soybean MON 87701 × MON 89788, which expresses the Cry1Ac protein, and its near non-Bt isoline A5547) where they remained until the adult stage. Due to gregarious behavior exhibited by first instar nymphs, they were individualized only when at the second instar. Adults were separated by sex and weighed, and pronotum width of each individual was subsequently measured. They were placed into plastic boxes containing soybean grains of the same soybean isoline as food source. Egg viability and female fecundity were assessed in adult individuals. Adult females of T. podisi (up to 24h old) were placed with eggs of E. heros from mothers reared on both soybean isolines. Nymphal development time, insect weight, pronotum width, sex ratio, female fecundity, and egg viability (% emergence) of Euschistus heros did not differ between treatments. Eggto-adult development time, female longevity, sex ratio, and percentage of parasitized eggs were not impacted by the Bt-soybean (expressing Cry1Ac protein). Results indicate that the Bt-soybean, MON 87701 × MON 89788, has no direct significant impact on the two studied species.