Interspecific insect relationships on Terminalia argentea (Myrtales: Combretaceae) trees in the Cerrado biome.

Terminalia argentea Mart. (Combretaceae), native to Brazil, is used in habitat restoration programs. Arthropods are bioindicators because their populations reflect changes in the environment. We evaluated the recovery of a degraded area by using ecological indices and analyzing arthropod interactions on T. argentea plants. The richness and diversity of sap-sucking Hemiptera and the abundance of tending ants and Sternorrhyncha predators increased with the number of T. argentea leaves. The correlation of the abundance of tending ants and Sternorrhyncha predators was positive with that of the sap-sucking Hemiptera, and the abundance of Sternorrhyncha predators was negative with that of tending ants and sap-sucking Hemiptera. The positive correlation between the abundance, richness, and diversity of insect groups and numbers of T. argentea leaves is an example of the bottom-up regulation mechanism, with the population dynamics of the lower trophic levels dictating those of higher trophic levels. The contribution of T. argentea, a host plant of many arthropods, to the recovery of ecological relationships between organisms in degraded ecosystems is important.

Evaluation of cold storage techniques to improve mass rearing of Cleruchoides noackae from Thaumastocoris peregrinus eggs.

The egg parasitoid Cleruchoides noackae Lin & Huber, 2007 (Hymenoptera: Mymaridae) is originated from Australia and the main biological control agent of Thaumastocoris peregrinus Carpenter & Dellapé, 2006 (Hemiptera: Thaumastocoridae) on Eucalyptus L'Hér (Myrtaceae). Companies that grow Eucalyptus are in need of a mass rearing protocol to increase the number of individuals produced and improve the quality of this parasitoid. The aim of this study was to define a protocol for mass rearing C. noackae in T. peregrinus eggs, based in the evaluations of the key biological attributes of this parasitoid in the parental and F1 generations, after the cold storage of the parasitised host eggs. Two methods were tested as C. noackae rearing protocols. In the first, parasitised eggs of T. peregrinus by C. noackae were cold stored for 7 days after being left in a climatic chamber at 24 ± 2°C, 60 ± 10% RH and a photoperiod of 12:12 (light:dark) h (standard environmental conditions) for 3, 6, 9 or 12 days. In the second, T. peregrinus eggs parasitised by C. noackae were maintained in a climatic chamber under standard environmental conditions for 6 days, after which these eggs were cold-stored for 0 (control), 7, 14 or 21 days. Parasitism (%), and the development period (parasitism to adult) and female proportion (%) of C. noackae were evaluated. Based on the results (parental generation: parasitism, around 45%; F1 generation: parasitism, around 55%; development period, around 16 days; female proportion, around 60%), eggs should be stored at 5°C on the sixth day after parasitism by C. noackae and maintained at this temperature for 7 days. The cold storage of T. peregrinus eggs, after parasitism, can be included in the mass rearing protocols of the parasitoid C. noackae.

Insecticidal and Repellent Activities of Four Essential Oils Against Sitophilus zeamais (Coleoptera: Curculionidae).

Objective: This study aimed to evaluate the efficacy of Corymbia citriodora, Melaleuca alternifolia (Myrtaceae), Mentha × piperita (Lamiaceae), and Schinus terebinthifolius (Anacardiaceae) essential oils as an alternative to manage Sitophilus zeamais (Coleoptera: Curculionidae) adults. Methods: Acute contact toxicity, acute toxicity on treated maize grain, fumigation toxicity, repellency bioassays, and GC-MS analysis of the essential oils were carried out. Results: Corymbia citriodora, M. alternifolia, M. × piperita, and S. terebinthifolius oils were toxic at different levels to S. zeamais through residual contact, ingestion and via fumigation, and were also repellent to adults of this pest. Melaleuca alternifolia oil was the most active in contact (LC50 = 18.98 µL.mL-1), ingestion (LC50 = 1.03 µL.g-1), and fumigant (LC50 = 20.05 µL.L-1 air) bioassays. Citronelal (53.6% in C. citriodora), terpinen-4-ol (46.9% in M. alternifolia), menthol (44.8% in M. × piperita), and ß-caryophyllene (16.2% in S terebinthifolius) are the major constituents of these oils. Conclusions: Melaleuca alternifolia and M. × piperita essential oils can be used by residual contact, while those of C. citriodora, M. alternifolia, and M. × piperita by mixing with maize grains. Melaleuca alternifolia essential oil can be used as a fumigant, while those of C. citriodora and S. terebinthifolius as repellents for S. zeamais adults.

Herbicides may threaten advances in biological control of diseases and pests.

Advances in agriculture include integrated methods of controlling pests, diseases, and weeds with biocontrollers, which are constantly increasing, along with herbicides. The objective is to present a systematic review of the main reports of herbicide effects on non-target organisms used in applied biological control and those naturally occurring in the ecosystems controlling pests. The categories were divided into predatory and parasitoid arthropods. Three hundred and fifty reports were analyzed, being 58.3% with parasitoids and 41.7% with predators. Lethal or sublethal effects of herbicides on reproduction, predation, genotoxicity, and abundance of biological control organisms have been reported. Two hundred and four reports of the impact of herbicides on parasitoids were analyzed. The largest number of reports was with parasitoids of the genus Trichogramma, with wide use in managing pests of the herbicide-tolerant transgenic plants. Most tests evaluating effects on parasitism, emergence, and mortality of natural enemies subjected to herbicides are with parasitoids of Lepidoptera eggs with a high diversity and use in managing these pests in different crops. Additive and synergistic effects of molecules increase the risks of herbicide mixtures. Herbicide use for weed management must integrate other control methods, as the chemical can impact natural enemies, reducing the biological control of pests.

Midgut Cell Damage and Oxidative Stress in Partamona helleri (Hymenoptera: Apidae) Workers Caused by the Insecticide Lambda-Cyhalothrin.

The stingless bee Partamona helleri plays a role in pollinating both native and cultivated plants in the Neotropics. However, its populations can be reduced by the pyrethroid insecticide lambda-cyhalothrin. This compound may cross the intestinal barrier and circulate through the hemolymph, affecting various non-target bee organs. The aim of the present study was to assess the extent of cellular damage in the midgut and the resulting oxidative stress caused by lambda-cyhalothrin in P. helleri workers. Bees were orally exposed to lambda-cyhalothrin. The lethal concentration at which 50% of the bees died (LC50) was 0.043 mg a.i. L-1. The P. helleri workers were fed this concentration of lambda-cyhalothrin and their midguts were evaluated. The results revealed signs of damage in the midgut epithelium, including pyknotic nuclei, cytoplasm vacuolization, changes in the striated border, and the release of cell fragments, indicating that the midgut was compromised. Furthermore, the ingestion of lambda-cyhalothrin led to an increase in the activity of the detoxification enzyme superoxide dismutase and the levels of the NO2/NO3 markers, indicating oxidative stress. Conversely, the activities of the catalase and glutathione S-transferase enzymes decreased, supporting the occurrence of oxidative stress. In conclusion, the ingestion of lambda-cyhalothrin by P. helleri workers resulted in damage to their midguts and induced oxidative stress.

Morphology and Morphometry of the Reproductive Tract of the Cotton Boll Weevil after Prolonged Feeding on Alternative Diets.

Anthonomus grandis Boheman (Coleoptera: Curculionidae) survives on alternative diets; however, this induces reproductive diapause. The objective was to evaluate the morphology and morphometry of the reproductive tract of this weevil after feeding on alternative diets. The experimental design was completely randomized with 160 replications and treatments arranged in a factorial design 3 × 3, represented by A. grandis adults fed on 3 food types (fragments of banana (T1) or orange (T2) endocarp, or with cotton squares of cultivar BRS 286 (T3, control)) and three evaluation periods (30, 60, and 90 days) and after each of these periods they were fed with cotton squares for 10 days. The reproductive tract of 100% of A. grandis females fed banana endocarp, orange endocarp, and cotton squares for 30 and 60 days and then cotton squares were morphologically adequate for reproduction, and after 90 days, only 50% of those fed cotton squares were in this condition. The length of the ovarioles and the width of the mature oocyte were greater for A. grandis fed on cotton squares and smaller in those with banana and orange endocarps. Histological sections reveal that male testes even with strong degenerative signals are already producing spermatozoa. On the other hand, females displayed ovaries with nurse cells in the tropharium and some maturing oocytes in the vitellarium. The body length was longer and the testis area and diameter smaller in males fed on cotton squares than in those with banana and orange endocarp. Anthonomus grandis females fed for ≥90 days with alternative food sources do not recover the functionality of their reproductive tract, even after consuming, for 10 days, a diet that favors reproduction. On the other hand, the males remain with their reproductive organs functional with this condition.

Contamination and mortality of leaf-cutting ant workers by the quinone inside inhibitor fungicide after social interactions.

Leaf-cutting ants of the genera Atta and Acromyrmex (Hymenoptera: Formicidae) are the most important pests in forest and agricultural plantations and livestock. Toxic baits are the main method to manage these insects. The objective was to determine whether the behavior of allogrooming, touch, and self-grooming among Atta sexdens rubropilosa Forel, 1908 (Hymenoptera: Formicidae) workers disperse the fungicide quinone inside inhibitor and whether this product is toxic to them. This fungicide was applied, topically, in groups of workers and the social interactions between them and their mortality with and without the fungicide were evaluated. The interactions and the quinone inside inhibitor fungicide contamination increased with the number of leaf-cutting ant workers per group. Excessive touches, with subsequent allogrooming, and self-grooming among the ant workers dispersed the quinone inside the inhibitor fungicide causing 100% mortality and indicating its toxicity to this insect. The hypothesis that social interactions contaminated ant colony mates and the toxicity of the fungicide quinone inside inhibitor to workers of the leaf-cutting ant A. sexdens rubropilosa was proven.

Selectivity of Insecticides to a Pupal Parasitoid, Trichospilus diatraeae (Hymenoptera: Eulophidae), of Soybean Caterpillars.

Selectivity is an important aspect of modern insecticides to be able to target pests whilst maintaining beneficial entomofauna in the crop. The present objective was to assess the selectivity of different insecticides for the pupal parasitoid of soybean caterpillars, i.e., Trichospilus diatraeae Cherian & Margabandhu, 1942 (Hymenoptera: Eulophidae). Acephate, azadirachtin, Bacillus thuringiensis (Bt), deltamethrin, lufenuron, teflubenzuron and thiamethoxam + lambda-cyhalothrin at the highest recommended concentrations for the soybean looper Chrysodeixis includens (Walker, [1858]) (Lepidoptera: Noctuidae), as well as water in the control, were used against the pupal parasitoid T. diatraeae. The insecticides and the control were sprayed on the soybean leaves, which were left to dry naturally and placed in cages with T. diatraeae females in each one. Survival data were submitted to analysis of variance (ANOVA) and the means were compared using Tukey's HSD test (α = 0.05). Survival curves were plotted according to the Kaplan-Meier method, and the pairs of curves were compared using the log-rank test at 5% probability. The insecticides azadirachtin, Bt, lufenuron and teflubenzuron did not affect T. diatraeae survival, while deltamethrin and thiamethoxam + lambda-cyhalothrin presented low toxicity and acephate was highly toxic, causing 100% mortality in the parasitoid. Azadirachtin, Bt, lufenuron and teflubenzuron are selective for T. diatraeae and could be used in IPM programs.

From the dual cyclone harvest performance of single conidium powder to the effect of Metarhizium anisopliae on the management of Thaumastocoris peregrinus (Hemiptera: Thaumastocoridae).

Insect pests introduced in eucalyptus plantations in Brazil are mostly of Australian origin, but native microorganisms have potential for their management. High quality biopesticide production based on entomopathogenic fungi depends on adequate technologies. The objective of this study was to evaluate Mycoharvester® equipment to harvest and separating particles to obtain pure Metarhizium anisopliae conidia to manage Thaumastocoris peregrinus Carpintero & Dellapé, 2006 (Hemiptera: Thaumastocoridae). The Mycoharvester® version 5b harvested and separated M. anisopliae spores. The pure conidia were suspended in Tween 80® (0.1%) and calibrated to the concentrations of 1 x 106, 107, 108 and 109 conidia/ml to evaluate the pathogenicity, lethal concentration 50 and 90 (LC50, LC90) and lethal time 50 and 90 (LT50, LT90) of this fungus to T. peregrinus. This equipment harvested 85% of the conidia from rice, with production of 4.8 ± 0.38 x 109 conidia/g dry mass of substrate + fungus. The water content of 6.36% of the single spore powder (pure conidia) separated by the Mycoharvester® was lower than that of the agglomerated product. The product harvested at the concentrations of 108 and 109 conidia/ml caused high mortality to T. peregrinus third instar nymphs and adults. The separation of conidia produced by solid-state fermentation with the Mycoharvester® is an important step toward optimizing the fungal production system of pure conidia, and to formulate biopesticides for insect pest management.

Morphoanatomical Changes in Eucalyptus grandis Leaves Associated with Resistance to Austropuccinia psidii in Plants of Two Ages.

The fungus Austropuccinia psidii infects young tissues of Eucalyptus plants until they are two years old in the nursery and field, causing Myrtaceae rust. The characteristics making older eucalypt leaves resistant to A. psidii and the reason for the low levels of this pathogen in older plants need evaluations. The aim of this study was to evaluate the morphological differences between Eucalyptus grandis leaves of different growth stages and two plant ages to propose a visual phenological scale to classify E. grandis leaves according to their maturation stages and to evaluate the time of leaf maturation for young and adult plants. A scale, based on a morphological differentiation for E. grandis leaves, was made. The color, shape and size distinguished the leaves of the first five leaf pairs. Anatomical analysis showed a higher percentage of reinforced tissue, such as sclerenchyma-like tissue and collenchyma, greater leaf blade thickness, absence of lower palisade parenchyma in the mature leaves and a higher number of cavities with essential oils than in younger ones. Changes in anatomical characteristics that could reduce the susceptibility of older E. grandis leaves to A. psidii coincide with the time of developing leaf resistance. Reduced infection of this pathogen in older plants appears to be associated with a more rapid maturation of their leaf tissues.

Diversity of entomopathogenic fungi from soils of eucalyptus and soybean crops and natural forest areas.

Soils present high fungal diversity, including entomopathogenic species. These fungi are used in pest control, providing easy production, multiplication, application, and dispersion in the field. The objective of the present study was to evaluate entomopathogenic fungal diversity in soils from eucalyptus and soybean crops and natural forest areas. These fungi were isolated using the "Bait Method" with Tenebrio molitor (Linnaeus, 1758) (Coleoptera: Tenebrionidae) larvae from 10 soil samples per area, collected at 10 cm deep in a zig-zag pattern. The isolated entomopathogenic fungi were cultivated in Petri dishes using PDA medium and their mycelia separated after seven days of incubation in a BOD-type chamber. Species of Aspergillus, Beauveria, Cordyceps, Fusarium, Metarhizium, Penicillium and Purpureocillium were identified. The "Bait Method" with T. molitor larvae is efficient to isolate entomopathogenic fungi with higher diversity from soils of the natural forest than the cultivated area.

New records of Ceratocampinae (Lepidoptera: Saturniidae) species from the Cerrado of Maranhão, Brazil / Novos registros de espécies de Ceratocampinae (Lepidoptera: Saturniidae) para o Cerrado do Maranhão, Brasil

Abstract Ceratocampinae (Lepidoptera: Saturniidae) is the second most diverse subfamily of Saturniidae with 300 species described in 30 genera from southern Canada to northern Argentina. Species of this subfamily are widely distributed in Southeast Brazil, with many endemics to the Cerrado, and important as indicators of ecosystem quality. Specimens of Ceratocampinae were collected in the Parque Estadual do Mirador, Maranhão state, Brazil. Adeloneivaia acuta (Schaus, 1896), Adeloneivaia schubarti Barros & O. Mielke, 1970, Eacles penelope (Cramer, 1775) and Megaceresa pulchra (Bouvier, 1923) are recorded for the first time in Maranhão state and Northeast Brazil and Eacles fairchildi May & Oiticica, 1941, only for Maranhão. The record of five Ceratocampinae (Saturniidae) species increases the knowledge on the diversity and the importance of preserving those of this subfamily in the Cerrado biome of Maranhão state and the Northeast region of Brazil.

Resumo Ceratocampinae (Lepidoptera: Saturniidae) é a segunda subfamília mais diversa de Saturniidae com 300 espécies descritas em 30 gêneros do sul do Canadá ao norte da Argentina. Espécies desta subfamília estão amplamente distribuídas no Sudeste do Brasil, com muitas endêmicas do Cerrado e importantes como indicadores da qualidade do ecossistema. Espécimes de Ceratocampinae foram coletados no Parque Estadual do Mirador, estado do Maranhão, Brasil. Adeloneivaia acuta (Schaus, 1896), Adeloneivaia schubarti Barros & O. Mielke, 1970, Eacles penelope (Cramer, 1775) e Megaceresa pulchra (Bouvier, 1923) são registradas pela primeira vez no estado do Maranhão e Nordeste do Brasil e Eacles fairchildi May & Oiticica, 1941 apenas para o Maranhão. O registro de cinco espécies de Ceratocampinae (Saturniidae) aumenta o conhecimento sobre a diversidade e a importância da preservação das espécies dessa subfamília no bioma Cerrado maranhense e na região Nordeste do Brasil.

Chemical composition of heartwood and sapwood of Tectona grandis characterized by CG/MS-PY.

Teak wood has chemical compounds that can be used for pharmaceutical and textile industries, in addition, this compounds are related to resistance to biodeterioration, color and modification processes. Heartwood and sapwood of T. grandis (teak), 15 years-old, were characterized by Py-CG/MS analysis and syringyl (S)/guaiacyl (G) ratio was evaluated. Heartwood and sapwood were pyrolyzed at 550 °C and 62 and 51 compounds were identified from them, respectively. The acetic acid (10%) and levoglucosan (26.65%) were the most abundant compound in the sapwood and heartwood, respectively. The high acetic acid content enhances the use of teak wood to production of artificial essences for perfumery, paints, dyes. While levoglucosan can be used in the manufacture of epoxy resins, antiparasitic and insecticides. The organic compounds identified include 2-methylanthraquinone as one of the main component responsible for the resistance of the teak wood to biological factors (fungi and termites). The syringyl (S)/guaiacyl (G) ratio of heartwood and sapwood was 0.51 and 0.50, respectively.

Entomopathogenic Fungi, Isolated From Soils and Bemisia tabaci (Hemiptera: Aleyrodidae) Adults, to Manage the Eucalyptus Red Gum Lerp Psyllid Glycaspis brimblecombei (Hemiptera: Aphalaridae).

The parasitoid Psyllaephagus bliteus Riek (Hymenoptera: Encyrtidae), entomopathogenic fungi, and chemical insecticides are the main strategies to manage the eucalypts pest Glycaspis brimblecombei Moore. The objective of this study was to isolate and to identify entomopathogenic fungi, collected from Bemisia tabaci Gennadius adults in soybean and tomato crops, and from soil samples in eucalypts, soybean, and native forest areas to evaluate their potential to manage G. brimblecombei. Twelve Beauveria and Cordyceps isolates were selected and compared with the commercial products Boveril Beauveria bassiana Bals. (Hypocreales: Cordycipitaceae), Metarril Metarhizium anisopliae Metschn. (Hypocreales: Clavicipitaceae), and Octane Cordyceps fumosorosea Wize (Hypocreales: Cordycipitaceae) and their respective strains. The fungal isolates were diluted in 0.1% aqueous Tween 80 at a concentration of 1.0 × 108 conidia/ml and sprayed on the G. brimblecombei nymphs with or without lerps. Pest mortality was higher and the TL50 and TL90 lower with the isolates LCBPF 11 C. javanica Frieder. & Bally (Hypocreales: Cordycipitaceae), LCBPF 12 (C. fumosorosea), and LCBPF 67 (C. fumosorosea) from B. tabaci adults. Fungi of the genera Beauveria and Cordyceps developed and caused high mortality of G. brimblecombei nymphs with lerps. The B. bassiana, C. cateniannulata Liang (Hypocreales: Cordycipitaceae), C. fumosorosea, C. javanica, and M. anisopliae isolates showed potential to manage G. brimblecombei. The lerp of this insect enhances entomopathogenic fungus development as a source of inoculum accelerating G. brimblecombei nymph mortality. Entomopathogenic fungi isolated from insects and soils are effective against G. brimblecombei and the presence of the lerp of this insect increases the effectiveness of its control.

The survival, development, and reproduction of Gonipterus platensis (Coleoptera: Curculionidae) on the main Eucalyptus (Myrtaceae) genotypes planted in Brazil.

Background: Gonipterus platensis Marelli (Coleoptera: Curculionidae) is the main defoliating beetle of Eucalyptus L'Hér. (Myrtaceae) plants worldwide. The suitability of Eucalyptus to this pest varies among host plant genotypes. The objective of this study was to evaluate the development, reproduction, and survival of G. platensis on Eucalyptus species and hybrids to assess their suitability to this insect pest in Brazil. Methods: The survival, development, and reproduction parameters were evaluated with G. platensis feeding leaves of Eucalyptus camaldulensis Dehnh., Eucalyptus grandis W. Hill., Eucalyptus urophylla S.T. Blake and on the hybrids of E. grandis ×E. urophylla 'H13' and 'VR3748' in the laboratory. Results: The duration of the larval stage of G. platensis was shorter on E. urophylla. The pupal stage and the period from larva to adult were equally shorter on E. urophylla and E. camaldulensis. The viability of instars of this insect was low on both E. grandis and E. camaldulensis. The complete lifespan, oviposition period and reproduction parameters of G. platensis were greater on E. urophylla, lower on E. camaldulensis and E. grandis, and intermediate on both hybrids tested. Synthesis: Eucalyptus urophylla is the most suitable host for G. platensis survival, development, and reproduction, while E. grandis and E. camaldulensis are the least suitable.

Development, Survival and Reproduction of Spodoptera frugiperda (Lepidoptera: Noctuidae) Fed an Artificial Diet or on Cotton, Castor Bean and Corn Leaves.

The polyphagy of Spodoptera frugiperda (Lepidoptera: Noctuidae) renders its control difficult because variations in the phenology of host plants grown in different seasons of the year and near each other can facilitate the movement of this pest between crops. The objective of this work was to examine certain biological characteristics of S. frugiperda fed on an artificial diet or on cotton, castor bean, or corn leaves. The experimental design was in randomized blocks, with four treatments represented by S. frugiperda caterpillars fed an artificial diet (T1) or pieces of cotton (T2), castor bean (T3) or corn (T4) leaves with five replications (five caterpillars per replication). The duration and survival of the egg, larva, pre-pupa, pupa and egg-adult period and the reproductive characteristics of this insect were determined. The survival, development and reproduction data of S. frugiperda originated from individuals reared with cotton and castor bean leaves were lower than those fed on corn leaves or an artificial diet. The number of nonviable eggs laid by females originated from caterpillars fed on castor bean leaves was higher than those fed on cotton and corn leaves or an artificial diet. The very higher number of unviable S. frugiperda eggs resulting from castor leaves can reduce outbreaks of this pest in cotton and corn crops after the cultivation of that plant, or by intercropping with this plant, in the main producing regions of Brazil.

Anatomical indicators of Eucalyptus spp. resistance to Glycaspis brimblecombei (Hemiptera: Aphalaridae).

The total area of forest crops in Brazil is 9.55 million hectares, of which 7.5 million hectares are Eucalyptus. These crops are the most productive in the world, but may suffer losses due to exotic pests, including Glycaspis brimblecombei Moore (Hemiptera: Aphalaridae) found in Brazil since 2003. Interactions between Eucalyptus plants and insect pests may led to the selection of resistant genotypes. Eucalyptus species are either susceptible or resistant to this pest group, but the damage they suffer needs to be evaluated. The objective was to determine possible leaf anatomy indicators of different Eucalyptus species associated with G. brimblecombei infestations, focusing on plant resistance to this pest. The study was carried out with Eucalyptus camaldulensis, Eucalyptus grandis, Eucalyptus saligna and Eucalyptus urophylla saplings infested or not by G. brimblecombei eggs and nymphs. Eighteen anatomical characteristics of the leaves of these plants were analyzed. The number of stomata on the adaxial and abaxial sides and the glandular area in the central leaf vein are associated with greater or lesser infestation by G. brimblecombei in the Eucalyptus genotypes.

Non-proteinaceous salivary compounds of a predatory bug cause histopathological and cytotoxic effects in prey.

N,N-dimethylaniline and 1,2,5-trithiepane, present in the salivary glands of Podisus nigrispinus Dallas (Heteroptera: Pentatomidae), are toxic compounds which kill prey. The insecticidal activity and midgut cytotoxicity in Spodoptera frugiperda (J. E. Smith (Lepidoptera: Noctuidae) caterpillars fed on a diet with lethal concentrations of N,N-dimethylaniline and 1,2,5-trithiepane were evaluated. Midgut cell damage was evaluated with both light and transmission electron microscopy. The LC50 and LC90 of N,N-dimethylaniline were 0.611 and 0.818 µg L-1, respectively, and for 1,2,5-trithiepane they were 0.671 and 0.885 µg L-1, respectively. Vacuolization in the digestive and goblet cells occurred after 1 h of exposure in the midgut of the insects treated with either N,N-dimethylaniline and 1,2,5-trithiepane. Changes caused by N,N-dimethylaniline and 1,2,5-trithiepane in the midgut of S. frugiperda caterpillars may affect digestion and nutrient absorption with negative impacts on the insect's development and survival. The non-proteinaceous N,N-dimethylaniline and 1,2,5-trithiepane compounds have insecticidal effects, confirming the potential use on S. frugiperda caterpillars through oral administration.

Chemical control of Acromyrmex lundi (Hymenoptera: Formicidae) in anthropic ecosystems.

BACKGROUND: Leaf-cutting ants are pests in agriculture, forests and pasture and, usually, controlled with toxic baits. The management and control of leaf-cutting ants is complex as a consequence of its sociability and behavior. We tested three toxic baits with abamectin, fipronil and sulfluramid to control colonies of Acromyrmex lundi Mayr, 1865 (Hymenoptera: Formicidae), in two seasons: 'Spring 2020' and 'Summer 2020/21', in Argentina. RESULTS: The percentage of effective bait carried in the spring was similar between treatments with 80%, 80% and 90% for those with abamectin, fipronil and sulfluramid. The ant flow of A. lundi decreased after toxic bait applications compared to the control through time in all treatments. This activity was higher in the spring than in the summer. The baits reduced the foraging activity of A. lundi from 5 to 96 days after application (DAA). Abamectin and fipronil baits controlled 50% and 67% of the nests in the spring, and 20% and 43% at 96 DAA in the summer. Sulfluramid was the best treatment, killing 90% of A. lundi nests. CONCLUSION: The baits decrease the foraging activity of A. lundi until 96 DAA, with total or partial death of its colonies varying between treatments. The ant symptoms with the sulfluramid bait appeared faster than with fipronil and may be a result of the low level of carry-over or differences in the chemical quality of the active ingredients. © 2022 Society of Chemical Industry.

Side-effects of pesticides on non-target insects in agriculture: a mini-review.

Climate change mediated by anthropogenic activity induces significant alterations on pest abundance and behavior and a potential increase in the use of agrochemicals for crop protection. Pesticides have been a tool in the control of pests, diseases, and weeds of agricultural systems. However, little attention has been given to their toxic effects on beneficial insect communities that contribute to the maintenance and sustainability of agroecosystems. In addition to pesticide-induced direct mortality, their sublethal effects on arthropod physiology and behavior must be considered for a complete analysis of their impact. This review describes the sublethal effects of pesticides on agriculturally beneficial insects and provides new information about the impacts on the behavior and physiology of these insects. The different types of sublethal effects of pesticides used in agriculture on pollinators, predators, parasitoids, and coprophagous insects were detailed.