Effects of Essential Oils on Biological Characteristics and Potential Molecular Targets in Spodoptera frugiperda.

Spodoptera frugiperda control methods have proved to be inefficient, which justifies the search for new control measures. In this search for botanical insecticides for controlling S. frugiperda, the following were evaluated: (i) the toxicity of essential oils (EOs) from Cinnamodendron dinisii, Eugenia uniflora, and Melaleuca armillaris; (ii) the effect of EOs on life table parameters against S. frugiperda; (iii) the chemical characterization of EOs; and (iv) the in silico interaction of the chemical constituents present in the three EOs with the molecular targets of S. frugiperda. The EO from E. uniflora had the lowest LD50 (1.19 µg of EO/caterpillar). The major compounds bicyclogermacrene (18.64%) in C. dinisii and terpinolene (57.75%) in M. armillaris are highly predicted to interact with the octopamine receptor (OctpR). The compound 1,8-cineole (21.81%) in M. armillaris interacts mainly with a tolerant methoprene receptor (MET) and curzerene (41.22%) in E. uniflora, which acts on the OctpR receptor. Minor compounds, such as nerolidol in C. dinisii and ß-elemene in E. uniflora, are highly ranked for multiple targets: AChE, MET, OctpR, and 5-HT1. It was concluded that the EO from E. uniflora negatively affects several biological parameters of S. frugiperda development and is promising as an active ingredient in formulations for controlling this insect pest.

Natural parasitism of the coffee leaf miner: climate factors, insecticide, and landscape affecting parasitoid diversity and their ecosystem services in coffee agroecosystems.

Climate factors, pesticides, and landscape in coffee agroecosystems directly affect the populations of the coffee leaf miner and its parasitoids. This study aimed to investigate the effects of climate factors, insecticide use, and landscape on natural parasitism, parasitoid diversity, and infestation of L. coffeella in coffee plantations in the Planalto region, Bahia, Brazil. Mined leaves were collected monthly in six coffee plantations with varying edge density, vegetation cover, landscape diversity in scales of 500 to 3000 m of radius, insecticide use, and climate factors. Closterocerus coffeellae, and Proacrias coffeae (Eulophidae) predominated in the pest's natural parasitism. Our record is the first for the occurrence of Stiropius reticulatus, Neochrysocharis sp. 1, Neochrysocharis sp. 2, and Zagrammosoma sp. in Bahia. Higher temperature and larger forest cover increased the coffee leaf miner infestation. Higher rainfall values, insecticide use, and landscape diversity decreased the pest infestations. Natural parasitism and species diversity are favoured by increase in temperature, forest cover, and edge density, while increase in rainfall, insecticide use, and landscape diversity lead them to decrease.The natural parasitism and diversity of parasitoid species of the coffee leaf miner have been enhancing in the areas with greater forest cover and edge density associated with low use of insecticides. The areas composed of different lands with annual croplands surrounding the coffee plantations showed less natural parasitism and parasitoid species diversity. The ecosystem services provided by C. coffeellae and P. coffeae in coffee crops areas require conservation and these species are potential bioproducts for applied biological control programmes.

Does the dose make the poison? Neurotoxic insecticides impair predator orientation and reproduction even at low concentrations.

BACKGROUND: Pesticides can be noxious to non-target beneficial arthropods and their negative effects have been recently recognized even at low doses. The predator Nesidiocoris tenuis (Reuter) (Hemiptera: Miridae) plays an important role in controlling insect pests in solanaceous crops, but its concurrent herbivory often poses relevant concerns for tomato production. Although insecticide side effects on N. tenuis have been previously studied, little is known on the potential implications of neurotoxic chemicals at low concentrations. We assessed the baseline toxicity of three neurotoxic insecticides (lambda-cyhalothrin, spinosad and chlorpyrifos) on N. tenuis by topical contact exposure. The behavioral and reproduction capacity of the predator was then investigated upon exposure to three estimated low-lethal concentrations (LC1 , LC10 and LC30 ). RESULTS: Predator survival varied among insecticides and concentrations, with LC30 /label rate ratios ranging from 8.45% to 65.40% for spinosad and lambda-cyhalothrin, respectively. All insecticides reduced the fertility of N. tenuis females at all estimated low-lethal concentrations. Chlorpyrifos seriously compromised predator orientation towards a host plant even at LC1 , while the same effect was observed for lambda-cyhalothrin and spinosad solely at LC30 . Lambda-cyhalothrin (at all concentrations) and chlorpyrifos (at LC10 and LC30 ) also affected the time taken by N. tenuis females to make a choice. CONCLUSION: The results indicate that all three insecticides can be detrimental to N. tenuis and should be avoided when presence of the predator is desirable. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Emergence and Infestation Level of Hypothenemus hampei (Coleoptera: Curculionidae) on Coffee Berries on the Plant or on the Ground During the Post-harvest Period in Brazil.

The coffee berry borer (CBB), Hypothenemus hampei Ferrari (Coleoptera: Curculionidae), is the most important coffee pest in most of the coffee growing countries. CBB females leave old dry berries after harvest and search for dry noninfested berries on the plant or on the ground to lay eggs or to use as refuge until new berries are available on the coffee trees in the following season. The CBB infestation level and emergence from berries on the ground or on the plants were evaluated in two fields post-harvest in the Spring in Brazil over two seasons. Twenty infested or noninfested berries in separate cages (250 ml plastic cups) were placed on the plants or on the ground under the tree canopy, in each field. The number of infested berries and CBB females that emerged from the infested berries were recorded weekly. CBB emergence was higher from berries on the ground than those on the coffee trees in both seasons, whereas CBB infestation was higher on coffee berries on the plants than those on the ground in season I. Insolation (hours of sunlight) and temperature were the main covariates that affected emergence and infestation by this insect. The results are discussed for monitoring CBB during the time of dispersal with implications on integrated management of this pest.

Ingestion and effects of cerium oxide nanoparticles on Spodoptera frugiperda (Lepidoptera: Noctuidae).

The objective of this study was to evaluate the biological and nutritional characteristics of Spodoptera frugiperda (Lepidoptera: Noctuidae), an arthropod pest widely distributed in agricultural regions, after exposure to nano-CeO2 via an artificial diet and to investigate the presence of cerium in the body of this insect through X-ray fluorescence mapping. Nano-CeO2, micro-CeO2, and Ce(NO3)3 were incorporated into the diet (0.1, 1, 10, and 100 mg of Ce L-1). Cerium was detected in caterpillars fed with diets containing nano-CeO2 (1, 10 and 100 mg of Ce L-1), micro-CeO2 and Ce(NO3)3, and in feces of caterpillars from the first generation fed diets with nano-CeO2 at 100 mg of Ce L-1 as well. The results indicate that nano-CeO2 caused negative effects on S. frugiperda. After it was consumed by the caterpillars, the nano-CeO2 reduced up to 4.8% of the pupal weight and 60% of egg viability. Unlike what occurred with micro-CeO2 and Ce(NO3)3, nano-CeO2 negatively affected nutritional parameters of this insect, as consumption rate two times higher, increase of up to 80.8% of relative metabolic rate, reduction of up to 42.3% efficiency of conversion of ingested and 47.2% of digested food, and increase of up to 1.7% of metabolic cost and 8.7% of apparent digestibility. Cerium caused 6.8-16.9% pupal weight reduction in second generation specimens, even without the caterpillars having contact with the cerium via artificial diet. The results show the importance of new ecotoxicological studies with nano-CeO2 for S. frugiperda in semi-field and field conditions to confirm the toxicity.

Detrimental sublethal effects hamper the effective use of natural and chemical pesticides in combination with a key natural enemy of Bemisia tabaci on tomato.

BACKGROUND: Bemisia tabaci (Hemiptera: Aleyrodidae) represents one of the greatest threats to agricultural crops. Chemical control is the primary tool used in integrated pest management (IPM) programs. However, release of the predator Nesidiocoris tenuis (Hemiptera: Miridae) on tomato plants is a highly recommended control tactic. The objective of this study was to evaluate the efficacy of a commercial borax plus citrus oil (BCO) product against B. tabaci in the presence and absence of N. tenuis. The synthetic insecticide lambda-cyhalothrin was used as a positive control. We also evaluated the sublethal effects of BCO on the behavior and predation rate of N. tenuis. RESULTS: Our results demonstrated that BCO, alone and at its maximum recommended field rate for B. tabaci, was not effective in controlling the pest under laboratory conditions. Application of BCO simultaneous with N. tenuis release did not reduce the increase in the B. tabaci population. Effective control of B. tabaci was achieved using only N. tenuis. However, synthetic lambda-cyhalothrin pyrethroid, used here as a control, caused high pest mortality and led to on-site extinction of N. tenuis, which did not occur for insects exposed to BCO. Lambda-cyhalothrin and BCO significantly affected the foraging behavior of N. tenuis, reducing the predation rate, especially following exposure to lambda-cyhalothrin. CONCLUSION: The insecticide lambda-cyhalothrin achieved satisfactory results in suppressing B. tabaci, but was harmful to N. tenuis. Additionally, lambda-cyhalothrin and BCO affected predator behavior. © 2020 Society of Chemical Industry.

Sublethal and transgenerational effects of thiamethoxam applied to cotton seed on Chrysoperla externa and Harmonia axyridis.

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. © 2018 Society of Chemical Industry.

Long-term effects of chlorantraniliprole reduced risk insecticide applied as seed treatment on lady beetle Harmonia axyridis (Coleoptera: Coccinellidae).

Chlorantraniliprole (CAP) is a reduced risk insecticide, which used as seed treatment in many crops. However, CAP residues can contaminate pollen and nectar, becoming a potential risk to beneficial arthropods. The aims of this study were to (1) determine the non-target effects of CAP seed treatment of cotton on Harmonia axyridis (Coleoptera: Coccinellidae) over two generations, and (2) assess the ability of the lady beetles to avoid plants grown from treated seeds. The exposure of H. axyridis larvae and adults to cotton seedlings grown from CAP treated seeds did not have a significantly affect on any life history parameters of the lady beetles directly exposed (F0). However, CAP caused significant transgenerational effects in the both larval and adult stages of H. axyridis. The CAP treatment of larvae exposure reduced the larval and pupal developmental time and the male body weight of F1 generation as well as the survival of the lady beetles over the developmental stages. In the adult bioassay, CAP seed treatment reduced both pupal developmental time and egg viability of F1 generation and decreased the survival of H. axyridis over the F1 generation developmental. In olfactometer test, only the H. axyridis larvae were able to avoid cotton seedlings grown from CAP treated seeds. The results of this study confirm the hypothesis that systemic insecticides, when applied to seed treatments, can cause negative effects on non-target organisms. In addition, the study emphasizes the importance of long-term assessments of the pesticides side-effects on beneficial arthropods.

Enzymatic biomarkers as tools to assess environmental quality: a case study of exposure of the honeybee Apis mellifera to insecticides.

The present study was intended to evaluate the responses of enzymes in the honeybee Apis mellifera after exposure to deltamethrin, fipronil, and spinosad and their use as biomarkers. After determination of the median lethal doses (LD50), honeybees were exposed at doses of 5.07 ng/bee and 2.53 ng/bee for deltamethrin, 0.58 ng/bee and 0.29 ng/bee for fipronil, and 4.71 ng/bee and 2.36 ng/bee for spinosad (equivalent to 1/10th [LD50/10] and 1/20th [LD50/20] of the LD50, respectively). The responses of acetylcholinesterase (AChE), carboxylesterases (CaEs-1-3), glutathione-S-transferase (GST), catalase (CAT), and alkaline phosphatase (ALP) were assessed. The results showed that deltamethrin, fipronil, and spinosad modulated these biomarkers differentially. For the enzyme involved in the defense against oxidative stress, fipronil and spinosad induced CAT activity. For the remaining enzymes, 3 response profiles were identified. First, exposure to deltamethrin induced slight effects and modulated only CaE-1 and CaE-2, with opposite effects. Second, spinosad exhibited an induction profile for most of the biomarkers, except AChE. Third, fipronil did not modulate AChE, CaE-2, or GST, increased CAT and CaE-1, and decreased ALP. Thus, this set of honeybee biomarkers appears to be a promising tool to evaluate environmental and honeybee health, and it could generate fingerprints to characterize exposures to pesticides.

Bioactivity of compounds from Acmella oleracea against Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) and selectivity to two non-target species.

BACKGROUND: Tropical plants are recognised sources of bioactive compounds that can be used for pest control. The objective of this study was to evaluate the biological activity of compounds present in Acmella oleracea (Asteracea) against Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), which is the main pest of tomato crops in Latin America. The selectivity of these compounds to the predator Solenopsis saevissima (Smith) (Hymenoptera: Formicidae) and to the pollinator Tetragonisca angustula (Latr.) (Hymenoptera: Apidae: Meliponinae) was also of interest. RESULTS: A bioassay screening with hexane and ethanol extracts from 23 plants was performed. The hexane extract of A. oleraceae was the most active of the extracts and was selected for further study. The following three alkamides were isolated from a hexane extract of the aerial parts of A. oleracea: spilanthol, (E)-N-isobutylundeca-2-en-8,10-diynamide and (R, E)-N-(2-methylbutyl)undeca-2-en-8,10-diynamide. All of the isolated compounds showed insecticidal activity, with spilanthol being the most active (LD(50) = 0.13 µg mg(-1) ) against T. absoluta. The alkamides were selective to both beneficial species studied. CONCLUSION: The crude hexane extract of A. oleraceae showed high insecticidal activity and can be used to control T. absoluta in organic or conventional crops. Quantification of LD(50) values of isolated compounds against T. absoluta showed that alkamides could serve as potent insecticides for T. absoluta control programmes. Spilanthol was the main alkamide active isolated. This alkamide is the most promising as it has the highest insecticidal activity and is selective to non-target organisms.

[Toxicity of pesticides recommended in the integrated apple production (IAP) to populations of Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae)]. / Toxicidade de pesticidas recomendados na produção integrada de maçã (PIM) a populações de Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae).

The goal of this work was to evaluate the effects of the pesticides abamectin, carbaryl, fenitrothion, methidathion, sulphur and trichlorfon on eggs of two Chrysoperla externa (Hagen) populations, as well as on the subsequent developmental stages and reproduction capacity of this green lacewing. Pesticide exposure and distilled water (control) were accomplished using a Potter's tower. None of the evaluated pesticides affected the egg viability of the C. externa populations studied, but abamectin and carbaryl caused significant mortality of other developmental stages of the predator. Sex ratio and reproduction capacity of females originated from treated eggs were unaffected. However, egg viability of C. externa from Bento Gonçalves, RS, Brazil, was reduced by sulphur. Considering to the total effect (E) of each pesticide, trichlorfon, fenitrothion, methidathion and abamectin were harmless to both C. externa populations (Bento Gonçalves and Vacaria), when applied on eggs, whereas carbaryl was slightly harmful. On the other hand, the fungicide sulphur was slightly harmful to C. externa from Bento Gonçalves, but harmless to those from Vacaria.

Toxicidade de pesticidas recomendados na produção integrada de maçã (PIM) a populações de Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) / Toxicity of pesticides recommended in the integrated apple production (IAP) to populations of Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae)

Os efeitos dos pesticidas abamectim, carbaril, fenitrotiom, metidatiom, enxofre e triclorfom foram avaliados sobre a fase de ovo de duas populações de Chrysoperla externa (Hagen), bem como sobre as fases subsequentes do desenvolvimento e reprodução do predador. A pulverização dos pesticidas e de água destilada (testemunha) sobre ovos de C. externa foi realizada por meio de torre de Potter. Nenhum dos pesticidas avaliados reduziu a viabilidade de ovos tratados, independente da população de C. externa estudada. Para as demais fases de desenvolvimento, apenas carbaril causou mortalidade acumulada significativa de ambas as populações quando em comparação aos demais pesticidas. A razão sexual dos adultos obtidos não foi afetada por nenhum dos compostos. Nenhum dos pesticidas afetou negativamente a capacidade de oviposição de fêmeas de C. externa oriundas de ovos tratados. No entanto, enxofre reduziu a viabilidade de ovos depositados por fêmeas da população de Bento Gonçalves. Considerando-se o efeito total (E) de cada pesticida, triclorfom, fenitrotiom, metidatiom e abamectim foram inócuos a ambas as populações de C. externa quando aplicados sobre seus ovos, enquanto carbaril foi considerado levemente prejudicial; o fungicida enxofre, por outro lado, foi considerado levemente prejudicial à população de Bento Gonçalves, e inócuo aos insetos da população de Vacaria.

The goal of this work was to evaluate the effects of the pesticides abamectin, carbaryl, fenitrothion, methidathion, sulphur and trichlorfon on eggs of two Chrysoperla externa (Hagen) populations, as well as on the subsequent developmental stages and reproduction capacity of this green lacewing. Pesticide exposure and distilled water (control) were accomplished using a Potter's tower. None of the evaluated pesticides affected the egg viability of the C. externa populations studied, but abamectin and carbaryl caused significant mortality of other developmental stages of the predator. Sex ratio and reproduction capacity of females originated from treated eggs were unaffected. However, egg viability of C. externa from Bento Gonçalves, RS, Brazil, was reduced by sulphur. Considering to the total effect (E) of each pesticide, trichlorfon, fenitrothion, methidathion and abamectin were harmless to both C. externa populations (Bento Gonçalves and Vacaria), when applied on eggs, whereas carbaryl was slightly harmful. On the other hand, the fungicide sulphur was slightly harmful to C. externa from Bento Gonçalves, but harmless to those from Vacaria.

Toxicidade de produtos fitossanitários utilizados na cultura do crisântemo para ovos e ninfas de Orius insidiosus ( Say ) ( Hemiptera: Anthocoridae ) / Toxicity of pesticides used in chrysanthemum crops to eggs and nymphs of Orius insidiosus ( Say ) ( Hemiptera: Anthocoridae )

O objetivo do presente estudo foi avaliar a toxicidade de alguns produtos fitossanitários utilizados na cultura do crisântemo para ovos e ninfas de Orius insidiosus (Say). Os bioensaios foram conduzidos em condições de laboratório a 25 ± 2°C, UR de 70 ± 10 por cento e fotofase de 12h. O contato dos produtos com os ovos foi realizado pela imersão de hastes de picão-preto (Bidens pilosa L.), previamente expostas para oviposição, nas caldas químicas dos produtos por um período de cinco segundos. Os produtos foram aplicados sobre ninfas por meio de torre de Potter. Foram utilizadas 40 ninfas de primeiro ínstar e 20 ninfas de segundo ínstar de O. insidiosus por tratamento. Adultos oriundos de ovos e ninfas tratados foram agrupados em casais para estudar o efeito dos produtos sobre seus parâmetros reprodutivos. Nenhum dos compostos avaliados afetou a viabilidade dos ovos tratados. Azoxistrobim, benomil, imibenconazole, iprodione, metalaxil + mancozebe e triforine foram seletivos para os insetos de primeiro e segundo ínstares de O. insidiosus tratados, enquanto abamectina, acefato e clorfenapir mostraram-se tóxicos para indivíduos de ambos os ínstares. O período de pré-oviposição, o número médio diário de ovos colocados, o número total de ovos por dez dias e a viabilidade de ovos também não foram afetados negativamente por azoxistrobim, benomil, imibenconazole, iprodione, metalaxil + mancozebe e triforine. Esses compostos, devido à baixa toxicidade apresentada, podem ser recomendados em programas de manejo de doenças na cultura do crisântemo, em associação com O. insidiosus.

[Toxicity of pesticides used in chrysanthemum crops to eggs and nymphs of Orius insidiosus (Say) (Hemiptera: Anthocoridae)]. / Toxicidade de produtos fitossanitários utilizados na cultura do crisântemo para ovos e ninfas de Orius insidiosus (Say) (Hemiptera: Anthocoridae).

The objective of this study was to evaluate the toxicity of some pesticides used in chrysanthemum crops to eggs and nymphs of Orius insidiosus (Say). The bioassays were carried out at 25 +/- 2 degrees C, 70 +/- 10% RH and 12h photophase. For the tests with eggs, stems of Bidens pilosa L. previously exposed to predator oviposition were dipped for five seconds in aqueous dilution of the pesticides, using 40 eggs per treatment. The pesticides were applied on nymphs using a Potter's tower. Forty first-instar and twenty second-instar nymphs of O. insidiosus were used per treatment in the tests with nymphs. The adults from eggs and nymphs treated were grouped in couples to study the pesticides effects on its reproductive parameters. None tested pesticide affected the viability of treated eggs. Azoxystrobin, benomyl, imibenconazole, iprodione, metalaxyl + mancozeb and triforine were harmless to first- and second-instar nymphs of O. insidiosus, whereas abamectin, acephate and chlorfenapyr were shown to be harmful to nymphs of both first and second instars. The pre-oviposition period, the daily number of eggs, number of eggs in ten days, and egg viability were not affected by azoxystrobin, benomyl, imibenconazole, iprodione, metalaxyl + mancozeb and triforine. These pesticides, for showing low toxicity to the predator, can be recommended in disease management programs for chrysanthemum crops, in association with O. insidiosus.

Toxicidade de produtos fitossanitários utilizados na cultura do cafeeiro a larvas de Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) e efeitos sobre as fases subseqüentes do desenvolvimento do predador / Toxicity of pesticides used in coffee crops to larvae of Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) and their effects on subsequent stages of the predator

Avaliou-se a seletividade fisiológica de alguns produtos fitossanitários utilizados em cafeeiro a larvas de Chrysoperla externa (Hagen) e seus reflexos nas fases subseqüentes do desenvolvimento do predador. Os tratamentos avaliados, em g i.a./L de água foram: 1- endosulfam (Thiodan 350 CE - 1,75), 2- clorpirifós (Lorsban 480 CE - 1,2), 3- betaciflutrina (Turbo 50 CE - 0,013), 4- enxofre (Kumulus 800 PM - 4,0), 5- azociclotina (Peropal 250 PM - 0,31), 6- oxicloreto de cobre (Cuprogarb 500 PM - 5,0) e 7- testemunha (água). As pulverizações foram realizadas em larvas de primeiro, segundo e terceiro ínstares de C. externa, por meio de torre de Potter. Em seguida, as larvas foram individualizadas em tubos de vidro e mantidas em câmara climatizada regulada a 25 ± 2°C, UR de 70 ± 10 por cento e fotofase de 12h. A toxicidade dos produtos foi calculada em função do seu efeito total (E) e categorizada conforme escala proposta pela IOBC. Clorpirifós e betaciflutrina foram nocivos a larvas de primeiro ínstar (E > 99 por cento) e os demais foram seletivos. Clorpirifós foi também tóxico a larvas de segundo e terceiro ínstares, sendo os demais compostos inócuos ao predador (E < 30 por cento). Nenhum dos produtos avaliados afetou a duração e sobrevivência de pupas, ou a razão sexual e fase adulta dos indivíduos provenientes de larvas tratadas. Endosulfam, enxofre, azociclotina e oxicloreto de cobre foram seletivos para larvas de primeiro, segundo e terceiro ínstares de C. externa e não afetaram as fases subseqüentes do desenvolvimento desse crisopídeo, podendo ser utilizados no manejo de pragas na cultura do cafeeiro.

The objective was to evaluate the selectivity of pesticides used in coffee crops to larvae of Chrysoperla externa (Hagen) and their effects on the subsequent developmental stages of the predator. The treatments in g a.i./L of water were: 1 - endosulfan (Thiodan 350 CE - 1.75), 2 - chlorpyrifos (Lorsban 480 CE - 1.2), 3 - betacyfluthrin (Turbo 50 CE - 0.013), 4 - sulphur (Kumulus 800 PM - 4.0), 5 - azocyclotin (Peropal 250 PM - 0.31), 6 - copper oxichloride (Cuprogarb 500 PM - 5.0) and 7 - control (water). The products were sprayed on first, second and third-instar larvae using a Potter's tower. The larvae were individualized in glass tubes and maintained at 25 ± 2°C, RH of 70 ± 10 percent and 12h photophase. The toxicity of the pesticides was calculated based in their total effect (E) and classified according to recommendations of IOBC. Chlorpyrifos and betacyfluthrin were harmful to first-instar larvae (E > 99 percent). Endosulfan, sulphur, azocyclotin and copper oxichloride were harmless to first-instar larvae and the others were selective. Chlorpyrifos was also toxic to second and third-instar larvae, and the other compounds were selective (E < 30 percent). None of the pesticides affected the duration and survival rate of pupae or the sex ratio of the adults originated from treated larvae. Endosulfan, sulphur, azocyclotin and copper oxichloride were harmless to the larval stage of C. externa and did not affect the subsequent stages, so that they can be recommended in IPM programs for the coffee crop.

Silicon and acibenzolar-S-methyl as resistance inducers in cucumber, against the whitefly Bemisia tabaci ( Gennadius ) ( Hemiptera: Aleyrodidae ) biotype B

O objetivo deste trabalho foi avaliar o efeito de silicato de cálcio (CaSiO3) e do ativador acibenzolar-S-methyl (BTH) na indução de resistência em pepino à mosca-branca Bemisia tabaci (Gennadius) biótipo B. Testes de preferência com e sem chance de escolha e de antibiose foram realizados em casa-de-vegetação e no laboratório do Departamento de Entomologia da Universidade Federal de Lavras/UFLA, MG. O delineamento foi o inteiramente ao acaso com os seguintes tratamentos: 1) testemunha, 2) aplicação de 3 g de silicato de cálcio.kg-1 de substrato, 3) duas aplicações de 200 ml de solução a 1% de silicato de cálcio/vaso, 4) duas aplicações de 100 ml de solução a 0,005% de BTH/vaso e 5) aplicação de silicato de cálcio e BTH na mesma dose dos tratamentos 3 e 4. Para eliminar o efeito isolado do cálcio, foi aplicado 1g de carbonato de cálcio.kg-1 de substrato no tratamento 1 (testemunha). O silicato de cálcio e BTH causaram efeitos negativos na população da mosca-branca pela redução da oviposição, aumento do ciclo biológico e da mortalidade na fase de ninfa. Apresentaram-se, assim, como produtos alternativos a serem utilizados no manejo integrado de mosca-branca na cultura de pepino.

Seletividade de inseticidas para ovos e ninfas de Orius insidiosus ( Say ) ( Hemiptera: Anthocoridae ) / Selectivity of inseticides to eggs and nymphs of Orius insidiosus ( Say ) ( Hemiptera: Anthocoridae )

O predador Orius insidiosus (Say) alimenta-se de tripes, afídeos, moscas-brancas, ácaros e pequenas lagartas, contribuindo para a regulação populacional dessas pragas em diferentes agroecossistemas. Este trabalho teve por objetivo avaliar a seletividade dos inseticidas abamectina, cartape, ciromazina, fempropatrina e imidaclopride, registrados para a cultura do crisântemo, para ovos e ninfas de 1°, 2° e 3° instares de O. insidiosus. Os produtos foram pulverizados em torre de Potter, sendo utilizadas as maiores doses recomendadas para o controle de pragas na cultura do crisântemo. Após a pulverização, os ovos e ninfas foram mantidos em condições controladas, com temperatura de 25 ± 1°C, UR de 70 ± 10 por cento e fotofase de 12h. Avaliaram-se a duração do período embrionário, a viabilidade dos ovos e a duração e sobrevivência de ninfas. Os ovos de O. insidiosus foram tolerantes a todos os inseticidas. Cartape e ciromazina foram seletivos às ninfas de 1°, 2° e 3° ínstares, enquanto que os demais produtos foram tóxicos. Fempropatrina provocou 100 por cento de mortalidade de O. insidiosus nos três ínstares avaliados. Os inseticidas cartape e ciromazina podem ser recomendados para uso em programas de manejo integrado de pragas na cultura do crisântemo.

Silicon influence on the tritrophic interaction: wheat plants, the greenbug Schizaphis graminum (Rondani) (Hemiptera: Aphididae), and its natural enemies, Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) and Aphidius colemani viereck (Hymenoptera: Aphidiidae) / Influência do silício na interação tritrófica: plantas de trigo, pulgão-verde Schizaphis graminum (Rondani) (Hemiptera: Aphididae) e seus inimigos naturais Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) e Aphidius colemani viereck (Hymenoptera: Aphidiidae)

Estudou-se a interação tritrófica: trigo, pulgão-verde Schizaphis graminum (Rondani) e seus inimigos naturais-chave Chrysoperla externa (Hagen) e Aphidius colemani Viereck, em plantascom ou sem adubação de silício. Os tratamentos consistiram em: 1) aplicação de silício via foliar; 2)aplicação de silício no solo e 3) testemunha (sem aplicação). As avaliações consistiram: a) teste depreferência do pulgão com chance de escolha em laboratório e b) aspectos biológicos das fases imaturas do predador C. externa, alimentado com pulgões criados em plantas dos diferentes tratamentos. Para a realização dos bioensaios com A. colemani foram realizados dois tratamentos: 1) aplicação de silício nosolo e 2) testemunha (sem aplicação). As características biológicas avaliadas foram: duração da fase imatura, longevidade, razão sexual, ciclo total e porcentagem de parasitismo. Verificou-se que a aplicação de silício aumentou o grau de resistência das plantas de trigo diminuindo a preferência do pulgão-verde em relação à testemunha. Esse resultado pode estar relacionado à barreira mecânica proporcionada peladeposição de sílica na parede celular, o que dificultaria a penetração do estilete no tecido da planta, como também ao aumento na síntese de compostos de defesa da planta. Entretanto, não foi observado nenhum efeito indireto da aplicação de silício nas características biológicas tanto do predador como doparasitóide.

We studied the tritrophic interaction: wheat, greenbug Schizaphis graminum (Rondani) and its key natural enemies, Chrysoperla externa (Hagen) and Aphidius colemani Viereck, in plantswith or without silicon fertilization. Treatments consisted of: 1) silicon application via the leaves; 2) silicon application in the soil 3) control (no application). The evaluations consisted of: a) free-choice aphid preference test in the laboratory, from the 35th day after plant emergence, and b) biological aspects of the immature stages of predator C. externa, feeding on aphids reared on plants from the differenttreatments. Two treatments were tried in the bioassays involving A. colemani: 1) silicon application in the soil, and 2) control (no application). The biological traits evaluated were: duration of the immature stage, longevity, sex ratio, total developmental time, and percentage parasitism. Silicon application increased the degree of resistance in wheat plants, decreasing greenbug preference in relation to thecontrol. This result could be related to the mechanical barrier provided by silica deposition in the cell wall, which would make it difficult for the stylet to penetrate the plant tissue, as well as an increase in the synthesis of plant defense compounds. However, no indirect effect of silicon application was observed on the biological traits of either the predator or the parasitoid.

Seletividade de inseticidas utilizados na cultura dos citros para ovos e larvas de Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) / Selectivity of insecticides used in citrus crops to eggs and larvae of Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae)

The objective of this work was to evaluate the selectivity of abamectin (0.0054 g a.i. L-1), deltamethrin (0.0125 g a.i. L-1), fenbutatin oxide (0.4 g a.i. L-1), lufenuron (0.0375 g a.i. L-1), tebufenozide (0.12 g a.i. L-1) and thiacloprid (0.036 g a.i. L-1) to eggs and larvae of Chrysoperla externa (Hagen). Commercial formulations of the insecticides were diluted in water and sprayed, using a Potter’s tower,at 1.5 ± 0.5 mg.cm-2, either on eggs or on glass plates, where first, second and third-instar larvae were placed to assess the contact action on them. Egg viability, survival of larvae, pupae and adults, and the effects of the compounds on the reproductive capacity of individuals were evaluated. The total toxic effect (E) of the insecticides was calculated according to the standard methodology established by IOBC. All tested insecticides were selective for eggs of C. externa. Lufenuron and deltamethrin were highly toxic to first, second and third-instar larvae of C. externa (E > 99% of mortality). Abamectin, fenbutatin oxide, tebufenozide and thiacloprid were moderately toxic to larvae of C. externa. First-instar larvae were the most sensitive to the compounds. All tested insecticides need to be tested undergreenhouse and field conditions, to further evaluate their suitability for IPM programs in citrus crops.

Objetivou-se neste trabalho avaliar a seletividade dos inseticidas abamectina (0,0054 g i.a. L-1), deltametrina (0,0125 g i.a. L-1), óxido de fenibutatina (0,4 g i.a. L-1), lufenurom (0,0375 g i.a. L-1), tebufenozide (0,12 g i.a. L-1) e tiaclopride (0,036 g i.a. L-1) para ovos e larvas de Chrysoperla externa (Hagen). Os inseticidas foram pulverizados, por meio de torre de Potter, garantindo a aplicação de 1,5± 0,5 mg/cm2, nos ovos ou em placas de vidro, sobre as quais foram colocadas larvas de primeiro, segundo e terceiro ínstares. Avaliaram-se a viabilidade dos ovos, a sobrevivência de larvas, pupas eadultos e o efeito dos inseticidas na capacidade reprodutiva dos indivíduos oriundos de ovos e de larvas tratadas. A toxicidade dos inseticidas foi calculada em função do seu efeito total (E), conforme metodologia padrão estabelecida pela “IOBC”. Todos os inseticidas foram seletivos para ovos de C. externa. Lufenurom e deltametrina foram altamente nocivos a larvas de primeiro, segundo e terceiro ínstares de C. externa (E > 99% de mortalidade). Abamectina, óxido de fenibutatina, tebufenozide e tiaclopride apresentaram toxicidade intermediária à fase larval de C. externa. O primeiro ínstar dessepredador foi o mais susceptível à ação dos produtos avaliados. Recomenda-se avaliar os efeitos dos inseticidas testados para larvas de C. externa em condições de casa de vegetação e campo para confirmação de sua toxicidade e possível utilização em programas de manejo integrado de pragas em citros.

Seletividade de seis inseticidas utilizados em citros a pupas e adultos de Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) / Selectivity of six insecticides used in citrus crops on pupae and adults of Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae)

The selectivity of the insecticides abamectin, lufenuron, fenbutatin oxide, tebufenozide, thiacloprid and deltamethrin used in citrus crops was evaluated for pupae and adults of Chrysoperla externa (Hagen). The experiments were conducted in the Entomology Department of the Universidade Federal de Lavras, MG, Brazil. The spraying was accomplished by means of Potter tower with volume ofapplication of 1.5 ± 0.5 mg/cm2. After spraying, the pupae were kept in test tubes in a climatic chamber and the adults in PVC cages in a room at 25 ± 2oC, 70 ± 10% RH and 12h photophase. A completely randomized experimental design was used, with six products and ten replicates, each one composed of three pupae or a pair of adults. The action of lufenuron on males or females of C. externa was also evaluated under acompletely randomized design with three treatments and ten replicates, each one composed of one pair. The insecticides were classified following the method established by the International Organization for Biological and Integrated Control of Noxious Animals and Plants (IOBC). All compounds were selective to the pupae (E < 30% of mortality). However, thiacloprid and deltamethrin were toxic to the adults (E > 99% of mortality), whereas fenbutatin oxide and tebufenozide were selective. Lufenuron reduced the survival rate of the egg when sprayed on the females. Thus, the results indicate that only fenbutatin oxide and tebufenozide could be used with C. externa in integrated pest management programs in citrus crops.

Avaliou-se a seletividade dos inseticidas abamectina, lufenurom, óxido de fenbutatina, tebufenozide, tiaclopride e deltametrina utilizados em citros para pupas e adultos de Chrysoperla externa (Hagen). Os experimentos foram conduzidos no Departamento de Entomologia da UFLA, Lavras, MG. As pulverizações foram realizadas por meio de torre de Potter utilizando-se 1,5 ± 0,5 mg/ cm2. Após a pulverização, as pupas foram colocadas em tubos de vidro e mantidas em câmara climática,e os adultos em gaiolas de PVC em sala climatizada (25 ± 2oC, 70 ± 10% UR e fotofase de 12h). O delineamento experimental foi inteiramente casualizado com seis inseticidas e dez repetições, sendo cada uma formada por três pupas ou um casal de adultos. Também foi avaliado o efeito do lufenurom na capacidade reprodutiva quando pulverizado sobre machos ou fêmeas desse predador. Os produtosforam enquadrados em classes de toxicidade seguindo metodologia estabelecida pela Organização Internacional para Controle Biológico e Integrado de Animais e Plantas Nocivos (IOBC). Todos os produtos foram seletivos para pupas (E < 30% de mortalidade). Tiaclopride e deltametrina foram tóxicos aos adultos (E > 99% de mortalidade), sendo que óxido de fenbutatina e tebufenozide mostraram-seseletivos. Quando pulverizado somente sobre fêmeas de C. externa, lufenurom reduziu significativamente a viabilidade de ovos. Os produtos óxido de fenbutatina e tebufenozide, em função da baixa toxicidade apresentada, podem ser recomendados no manejo integrado de pragas na cultura dos citros emassociação com C. externa.