A MaxEnt Model of Citrus Black Fly Aleurocanthus woglumi Ashby (Hemiptera: Aleyrodidae) under Different Climate Change Scenarios.

The citrus blackfly (CBF), Aleurocanthus woglumi Ashby, is an exotic pest native to Southeast Asia that has spread rapidly to the world's main centers of citrus production, having been recently introduced to Brazil. In this study, a maximum entropy niche model (MaxEnt) was used to predict the potential worldwide distribution of CBF under current and future climate change scenarios for 2030 and 2050. These future scenarios came from the Coupled Model Intercomparison Project Phase 6 (CMIP6), SSP1-2.6, and SSP5-8.5. The MaxEnt model predicted the potential distribution of CBF with area under receiver operator curve (AUC) values of 0.953 and 0.930 in the initial and final models, respectively. The average temperature of the coldest quarter months, precipitation of the rainiest month, isothermality, and precipitation of the driest month were the strongest predictors of CBF distribution, with contributions of 36.7%, 14.7%, 13.2%, and 10.2%, respectively. The model based on the current time conditions predicted that suitable areas for the potential occurrence of CBF, including countries such as Brazil, China, the European Union, the USA, Egypt, Turkey, and Morocco, are located in tropical and subtropical regions. Models from SSP1-2.6 (2030 and 2050) and SSP5-8.5 (2030) predicted that suitable habitats for CBF are increasing dramatically worldwide under future climate change scenarios, particularly in areas located in the southern US, southern Europe, North Africa, South China, and part of Australia. On the other hand, the SSP5-8.5 model of 2050 indicated a great retraction of the areas suitable for CBF located in the tropical region, with an emphasis on countries such as Brazil, Colombia, Venezuela, and India. In general, the CMIP6 models predicted greater risks of invasion and dissemination of CBF until 2030 and 2050 in the southern regions of the USA, European Union, and China, which are some of the world's largest orange producers. Knowledge of the current situation and future propagation paths of the pest serve as tools to improve the strategic government policies employed in CBF's regulation, commercialization, inspection, combat, and phytosanitary management.

Bioactivity of essential oils from Croton grewioides and its major compounds: toxicity to soybean looper Chrysodeixis includens and selectivity to the predatory stink bug Podisus nigrispinus.

Natural biological control is a key factor that ensures the regulation of insect pest populations in agroecosystems. However, the indiscriminate use of pesticides has compromised this environmental service. Thus, the search for environmentally safe pesticides is an increasing requirement for sustainable food production. In this study, we analyzed the toxicity of essential oils from two accessions (CGR112 and CGR126) of Croton grewioides and its major compounds, methyl eugenol and eugenol, on the soybean pest Chrysodeixis includens. In addition, we investigated the sublethal effects of these compounds on the predatory bug Podisus nigrispinus, analyzing its developmental, reproduction and life table parameters. Essential oils and their major compounds were toxic to C. includens and P. nigrispinus. In general, the presence of eugenol made the essential oil more toxic to the pest and selective to the natural enemy. Eugenol was the most toxic compound for 2nd instar larvae of C. includens at LD50, followed by CGR126 essential oil from C. grewioides which was equally toxic at higher doses. The estimated lethal times for essential oils to cause mortality in 50% of the population of C. includens were less than 15 h. There was selectivity of the essential oil of CGR126 accession of C. grewioides at lethal doses above 90%. Although the treatments showed little effect on the development of P. nigrispinus, body mass and reproductive parameters were negatively affected, with the exception of the essential oil of CGR126 accession of C. grewioides. The essential oil of C. grewioides may be a promising active ingredient for the synthesis of new insecticides, which are efficient against C. includens and at the same time are safer for the natural enemy P. nigrispinus.

Lethal and sublethal effects of an emulsion based on Pogostemon cablin (Lamiaceae) essential oil on the coffee berry borer, Hypothenemus hampei.

The global search for eco-friendly and human-safe pesticides has intensified, and research on essential oils (EOs) has expanded due to their remarkable insecticidal activities and apparent human-safe. Despite this, most of the literature focuses on short-term and simplified efforts to understand lethal effects, with only a few comprehensive studies addressing sublethal exposures. To fill this shortcoming, we explore the lethal and sublethal effects of Pogostemon cablin (Lamiaceae) EO and an EO-based emulsion (18%) using the coffee berry borer Hypothenemus hampei Ferrari (Coleoptera: Curculionidae: Scolytinae) as a model. First, we determine the toxicity of EO and EO-based emulsion using dose-mortality curves and lethal times. Second, we subjected adult females of H. hampei to sublethal doses to assess whether they affected their behavior, reproductive output, and histological features. Our findings reveal that patchoulol (43.05%), α-Guaiene (16.06%), and α-Bulnesene (13.69%) were the main components of the EO. Furthermore, the EO and its emulsion had similar toxicity, with dose-mortality curves and lethal times overlapping 95% confidence intervals. We also observed that sublethal exposure of females of H. hampei reduces reproduction and feeding, increases walking activity, and causes histopathological changes in the midgut. This study advances the knowledge of the lethal and sublethal effects of an eco-friendly substance on insects.Responsible Editor: Giovanni Benelli.

The seasonal dynamic of Tuta absoluta in Solanum lycopersicon cultivation: Contributions of climate, plant phenology, and insecticide spraying.

BACKGROUND: A variety of abiotic and biotic factors promoting seasonal variation in the population of insect pests. Knowledge of the timing and magnitude of these factors is important for the study of population dynamics and the development of efficient pest management programs. Currently, there are few studies regarding Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) seasonal dynamics in tomato cultivation under open field conditions, either with or without insecticide application. This study aimed to investigate the effects of tomato phenology, climatic factors, and insecticide spraying on the seasonal dynamics of T. absoluta in tomato cultivation under open field conditions, using data from monitoring performed for 3 years. RESULTS: Insecticide, host plant, and climatic conditions can affect T. absoluta life cycles directly over time, resulting in shifts of peaks of the pest. Insecticides for T. absoluta control reduced injury caused by larvae; however, this was not enough to reduce the density below economic injury levels (EIL) during periods of climatic conditions more suitable for population growth. Tuta absoluta densities surpassed EIL more frequently during the tomato plant fruiting stage. The highest densities of mines and damaged fruits occurred during periods of August to January and September to January in crops without and with the application of insecticides, respectively. Regarding the climatic factors, the highest densities of T. absoluta occurred during periods of increasing air temperature and low rainfall. CONCLUSION: This study provides relevant insights into the factors that regulate the dynamics of T. absoluta in tomato cultivation and the decision-making process of control of this pest. © 2021 Society of Chemical Industry.

Mass spectrometry characterization, antioxidant activity, and cytotoxicity of the peel and pulp extracts of Pitomba.

The fruit of the Talisia esculenta tree, is largely consumed and appreciated for its bittersweet taste; however, detailed information on its constituent bioactive compounds is still scarce. Therefore, this study aims to screen the antioxidant activity by six methods and determine the chemical profile of the pitomba fruit peel and pulp by electrospray ionization-Fourier transform-mass spectrometry. This is the first study attempting to identify the bioactive compounds in the pitomba fruit peel. Consequently, 19 and 14 compounds were identified in the ethanolic and hexanic peel extracts, while 7 and 10 compounds were detected in the ethanolic and hexanic pulp extracts, respectively. The common compounds across the board were citric acid, ascorbic acid, and shikimic acid. In addition, the ethanolic peel extract exhibited a high 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity (54.21-81.41%). The obtained results highlight the importance the pitomba fruit as a promising source of natural compounds with high antioxidant activities.

Potential source of ecofriendly insecticides: Essential oil induces avoidance and cause lower impairment on the activity of a stingless bee than organosynthetic insecticides, in laboratory.

The negative effect of insecticides on bees has been reported as one of the factors associated with the decline in population of these pollinators. Thus, the aim of this study was to evaluate the response of the stingless bee Nannotrigona aff. testaceicornis (Lepeletier, 1836) to a promising source of new insecticide molecules obtained from Lippia sidoides (rosemary pepper) essential oil (EO) and its major compounds (thymol, ρ-cymene, and (E)-caryophyllene), comparing them to commercial insecticides (organosynthetic: imidacloprid, deltamethrin and semisynthetic: spinetoram). For this, stingless bees were exposed by contact with these compounds to evaluate the lethal and sublethal (locomotion and flight orientation) toxicity. The L. sidoides EO and its major compounds have low lethal toxicity to forager worker bees (N. aff. testaceicornis). The organosynthetics imidacloprid (LD50 =0.00146 µgbee-1) and deltamethrin (LD50 =0.0096 µg bee-1) were about 209,589 and 31,875 times more toxic, respectively, than the least toxic natural compound, (E)-caryophyllene (LD50 =306 µgbee-1). Locomotion ability and flight orientation were little affected by spinetoram and by L. sidoides EO and its major compounds, however, were greatly reduced by the imidacloprid and deltamethrin insecticides. Besides shows low lethal and sublethal toxicity, the bioinsecticides were also avoided by the forager bees. Individuals treated with the L. sidoides EO and thymol were avoided by the untreated bees. Therefore, the natural products studied here were promising due to their recognized effectiveness against pest insects and greater safety to bees N. aff. testaceicornis.

Wet and warm conditions contribute to the occurrence of the neotropical butterfly Ascia monuste orseis Godart (Lepidoptera: Pieridae) on Brassica crops.

Ascia monuste orseis Godart (Lepidoptera: Pieridae) is a neotropical butterfly distributed in South America. During the larval stage, this insect causes economic losses on Brassica crops. Wet and warm conditions are known to increase subspecies occurrence, but it remains unclear why these conditions are more suitable. In this study, we have shown that both conditions are highly favourable for A. monuste orseis. We determined the thermal requirements for immature development and then created models for A. monuste orseis occurrence using Climex algorithm. Two models were built: one for the year-round presence and other for seasonal suitability. We validated the models using subspecies occurrence records and monitoring in two Brazilian regions (Northeast and Southeast). The minimum, optimum and maximum temperature for immature development were estimated at 16.37, 29.16 and 34.95 °C, respectively. The model for year-round presence indicated tropical areas as highly suitable for A. monuste orseis occurrence (with 88% of accuracy) and the seasonal models showed unsuitable areas in some parts of South America during cold and dry periods. Such predictions were observed in the monitored areas where A. monuste orseis was not found. These results can be associated with the mortality caused by low temperature to immature stages and drought conditions that may induce adult migration to moist habitats. Thus, we suggest that A. monuste orseis occurs mainly during wet and warm seasons on Brassica crops due to deleterious effects caused by cold and dry conditions. This information can be used to improve A. monuste orseis management in Brassica crops.

Synergistic effect of aromatic plant essential oils on the ant Acromyrmex balzani (Hymenoptera: Formicidae) and antifungal activity on its symbiotic fungus Leucoagaricus gongylophorus (Agaricales: Agaricaceae).

Leaf-cutting ants have great potential for damage to agricultural and forest crops. Although chemical control is the most used method for the management of this pest, more friendly alternative methods have been investigated. Thus, this study aimed to evaluate the insecticidal and antifungal potential of essential oils obtained from Aristolochia trilobata, as well as the potential of two chemotypes of Myrcia lundiana and their major compounds (isopulegol and citral) on Acromyrmex balzani and its symbiotic fungus Leucoagaricus gongylophorus. Toxicity and synergism and/or antagonism tests were performed using essential oils and their major compounds on A. balzani ants. The antifungal activity of these compounds was tested on the fungus L. gongylophorus. The essential oils and their major compounds were toxic to A. balzani. The mixture of essential oils of A. trilobata with those of M. lundiana had higher toxicity to the ants. This synergistic effect is mainly due to the interactions between the citral compound and the major compounds present in A. trilobata essential oil. The essential oils of M. lundiana chemotypes showed antifungal properties against L. gongylophorus, and the citral compound proved to have fungicidal activity. These results show that the use of M. lundiana and A. trilobata essential oils and their major compounds is a potential alternative for the management of leaf-cutting ants A. balzani, as they have a toxic effect on worker ants and antifungal activity on their symbiotic fungus.

Toxicity of the essential oil of basil cultivars and hybrids and its repellent effect on stored grain pests / Toxicidade do óleo essencial de cultivares e híbridos de manjericão e seu efeito repelente sobre pragas de grãos armazenados

Essential oils have emerged as an alternative to synthetic insecticides in the control of stored grain pests. The toxicity and repellency of the essential oils of four basil cultivars and three basil hybrids and the monoterpenes linalool, citral, and (E)-methyl cinnamate were evaluated in the stored grain pests Callosobruchus maculatus and Sitophillus zeamais. The essential oils of the cultivar Genovese and the hybrid 'Genovese' x 'Maria Bonita' were more toxic to C. maculatus. Conversely, the essential oils of the cultivar Sweet Dani and the hybrid 'Cinnamom' x 'Maria Bonita' were more toxic to S. zeamais. Among the monoterpenes, (E)-methyl cinnamate was the most toxic to both pests, taking 0.14 and 0.34 µ L.mL-1 to kill 50% of the C. maculatus and S. zeamais populations, respectively. All essential oils from cultivars, hybrids, and monoterpenes were repellent to S. zeamais, except for (E)-methyl cinnamate. For C. maculatus, this effect was lower, being citral the most repellent compound. Results demonstrate the insecticidal potential of the essential oil of O. basilicum and its monoterpenes in the control of stored grain pests.

Os óleos essenciais surgem como alternativa aos inseticidas sintéticos no controle das pragas de grãos armazenados. A toxicidade e a repelência dos óleos essenciais de quatro cultivares e três híbridos de manjericão e dos monoterpenos linalol, citral e (E)-cinamato de metila foram avaliadas nas pragas de grãos armazenados Callosobruchus maculatus e Sitophillus zeamais. Os óleos essenciais da cultivar Genovese e do híbrido 'Genovese' x 'Maria Bonita' foram mais tóxicos para C. maculatus. Já para S. zeamais, os óleos essenciais das cultivar Sweet Dani e do híbrido 'Cinnamom' x 'Maria Bonita' apresentaram maior toxicidade. Dentre os monoterpenos, o (E)-cinamato de metila foi o mais tóxico para ambas as pragas. Foram necessários 0,14 e 0,34 µ L.mL-1 para matar 50% da população de C. maculatus e S. zeamais. Todos os óleos essenciais das cultivares, dos híbridos e dos monoterpenos foram repelentes a S. zeamais, com exceção do (E)-cinamato de metila. Já para C. maculatus, este efeito foi reduzido, sendo o citral o composto mais repelente. Nos resultados demonstram o potencial inseticida dos óleos essenciais de O. basilicum e seus monoterpenos para o controle de pragas de grãos armazenados.

Morpho-agronomic characterization of Varronia curassavica germplasm conservated "Ex situ" / Caracterização morfoagronômica de germoplasma de Varronia curassavica conservado "Ex situ"

Varronia curassavica Jacq. is a medicinal and aromatic plant native to Brazil. The essential oil of this species is valued by the pharmaceutical industry due to its bioactive substances containing anti-inflammatory properties. This study aimed to morpho-agronomically characterize 27 accessions of the collection of V. curassavica of the Active Germplasm Bank of Medicinal and Aromatic Plants of the Federal University of Sergipe. The experiment consisted of a randomized block design with three replications. The morphological characterization occurred in the field, by evaluating the variables plant height; canopy width; canopy shape; stem diameter; stem color; leaf blades width, length, and length/width ratio; leaves, petals, and sepals color. The agronomic characterization was performed using the essential oils extracted from dried leaves by hydrodistillation in a Clevenger apparatus. Leaves dry matter yield per plant and essential oil yield and content were also evaluated. The accessions showed great variation for leaves color, with different shades of green, which allowed separating them into dark green leaf and light green leaf plants. Plant height values ranged from 101.33 cm (VCUR-801) to 345.33 cm (VCUR-701). The clustering analysis of the traits revealed seven distinct groups. The accessions VCUR-103 and VCUR-001 were the most divergent, whereas the accessions VCUR-401 and VCUR-404 were the most similar. The morpho-agronomic characterization of V. curassavica accessions provides a correct description of the species by pointing out perspectives for genetic improvement, besides optimizing the conservation process. KEYWORDS: Cordiaceae. Medicinal plant. Aromatic plant. Essential oil. Domestication. Genetic breeding INTRODUCTION Brazil is rich in plant biodiversity (SOUZA et al., 2010). However, in recent years, its biodiversity has undergone accelerated destruction,mainly affecting the natural vegetation. This fact is due to agricultural expansion, fires, logging, extractivism, and uncontrolled urban growth. All these changes have posed a great threat to several plant species in the country (OLIVEIRA, 2010). An alternative for the maintenance and conservation of endangered species is the formationof collections in Active Germplasm Banks, which holds base collections for the conservation of a broad plant genetic variability, enabling biodiversity maintenance (SILVA et al., 2012). Varronia curassavica Jacq. (ex Cordia verbenacea DC.)] is a medicinal and aromatic plant native to Brazil, belonging to the Cordiaceae family (GASPARINO; BARROS, 2009). It occurs from Central America to southern Brazil (LORENZI; MATOS, 2008) in a wide range of habitats, such as beaches, restinga, forests, and cerrado (WANDERLEY et al., 2002). V. curassavica has stood out both in folk medicine and in the pharmaceutical industry, mainly due to the anti-inflammatory substances present in its essential oil (PASSOS et al., 2007; PARISSOTO et al., 2012; PIMENTEL et al., 2012). The effectiveness of V. curassavica is recognized by the National Sanitary Surveillance Agency (ANVISA). The plant is included in the List of the Unified Health System (SUS) and the National List of Medicinal Plants of Interest to the Unified Health System (RENISUS) (BRASIL, 2011). Due to its therapeutic properties, several studies have been developed aimed at the selection Received: 14/05/18 Accepted: 20/11/19

Varronia curassavica Jacq. é uma planta medicinal e aromática nativa do Brasil. O óleo essencial desta espécie é utilizado pela indústria farmacêutica por conter substâncias bioativas com propriedades anti-inflamatórias. Objetivou-se caracterizar morfoagronomicamente 27 acessos da coleção de V. curassavica do Banco Ativo de Germoplasma de Plantas Medicinais e Aromáticas da Universidade Federal de Sergipe. O delineamento experimental foi em blocos casualizados com três repetições. A caracterização morfológica foi realizada em campo, por meio da avaliação da altura da planta; largura da copa; formato da copa; diâmetro do caule a 10 cm do solo; cor do caule; largura, comprimento e relação comprimento/largura das lâminas foliares; e cor das folhas, pétalas e sépalas. A caracterização agronômica foi realizada a partir dos óleos essenciais extraídos de folhas secas por hidrodestilação em aparelho Clevenger. Foi avaliado o rendimento de massa seca das folhas por planta e o teor e rendimento do óleo essencial. Grande variação foi observada entre os acessos para a coloração das folhas, as quais apresentaram diferentes tonalidades de verde, sendo possível separá-las entre plantas com folhas verde-escuro e plantas com folhas verde-claro. Para a variável altura de planta, os valores variaram de 101,33 cm (VCUR-801) a 345,33 cm (VCUR-701). Sete grupos distintos foram formados na análise de agrupamento realizada a partir dos caracteres avaliados. Os acessos VCUR-103 e VCUR-001 foram os que se mostraram mais divergentes, enquanto que os mais semelhantes foram os acessos VCUR-401 e VCUR-404. A caracterização morfoagronômica dos acessos de erva-baleeira permitirá a realização de uma correta descrição da espécie, apontando perspectivas para o melhoramento genético, além de possibilitar a otimização do processo de conservação.

Insecticidal activity of indole derivatives against Plutella xylostella and selectivity to four non-target organisms.

The diamondback moth Plutella xylostella (Linnaeus, 1758) (Lepidoptera: Plutellidae) is a destructive pest of brassica crops of economic importance that have resistance to a range of insecticides. Indole derivates can exert diverse biological activities, and different effects may be obtained from small differences in their molecular structures. Indole is the parent substance of a large number of synthetic and natural compounds, such as plant and animal hormones. In the present study, we evaluate the insecticidal activity of 20 new synthesized indole derivatives against P. xylostella, and the selectivity of these derivatives against non-target hymenopteran beneficial arthropods: the pollinator Apis mellifera (Linnaeus, 1758) (Hymenoptera: Apidae), and the predators Polybia scutellaris (White, 1841), Polybia sericea (Olivier, 1791) and Polybia rejecta (Fabricius, 1798) (Hymenoptera: Vespidae). Bioassays were performed in the laboratory to determine the lethal and sublethal effects of the compounds on P. xylostella and to examine their selectivity to non-target organisms by topical application and foliar contact. The treatments consisted of two synthesized derivatives (most and least toxic), the positive control (deltamethrin) and the negative control (solvent). The synthesized compound 4e [1-(1H-indol-3-yl)hexan-1-one] showed high toxicity (via topical application and ingestion) and decreased the leaf consumption by P. xylostella, displaying a higher efficiency than the pyrethroid deltamethrin, widely used to control this pest. In addition, the synthesized indole derivatives were selective to the pollinator A. mellifera and the predators P. scutellaris, P. sericea and P. rejecta, none of which were affected by deltamethrin. Our results highlight the promising potential of the synthesized indole derivatives for the generation of new chemical compounds for P. xylostella management.

Conventional Sampling Plan for Scouting Neoleucinodes elegantalis (Lepidoptera: Crambidae) Eggs on Tomato Fruits.

The small tomato borer, Neoleucinodes elegantalis (Guenée), is an important pest of tomato (Solanum lycopersicum L.) in South and Central America. This pest is a potential threat for many tomato-producing areas and was listed in 2014 as an A1 quarantine pest by the European and Mediterranean Plant Protection Organization. Soon after hatching, the neonate N. elegantalis larvae penetrate the fruits where they feed until pupation. Therefore, effective N. elegantalis management relies on the timely scouting of egg densities to allow decision-making prior to penetration of neonates into fruits. This study aimed to develop a conventional sampling plan for scouting N. elegantalis eggs on tomato plants. The most representative and precise sampling unit was the most basal fruit cluster for plants bearing up to three clusters (S1 plants). For plants with more than three fruit clusters (S2 plants), the most representative and precise sampling unit was the combination of the second and third fruit clusters. Among the four variables evaluated (eggs/fruit, egg masses/fruit, percentage fruit with eggs, and percentage clusters with eggs), the percentage of clusters with eggs was the most economical for N. elegantalis sampling based on the number of samples and cost required. For this variable, the number of samples determined at the 25% error level was 42 and 36 samples for S1 and S2 plants, respectively. The sampling plan developed for scouting N. elegantalis is fast, reflects pest infestation in tomato fields, and costs less than US$1.50 per field scouted.

Essential oils from Varronia curassavica (Cordiaceae) accessions and their compounds (E)-caryophyllene and α-humulene as an alternative to control Dorymyrmex thoracius (Formicidae: Dolichoderinae).

The process of urbanization of natural environments has dramatically increased the incidence of pest insects. To control these organisms in urban environments, the last decades have been marked by an increase in the use of synthetic insecticides. However, the intensive and indiscriminate use of synthetic insecticides has provoked a series of environmental problems and human health. In this way, the concern and the searching for environmentally safer alternatives for the control of urban pests is increasing. In the present study we evaluated the lethal and sublethal effects of essential oils (EOs) of six accessions of Varronia curassavica (Jacq.) (Cordiaceae) and their constituents (E)-caryophyllene and α-humulene on the ant Dorymyrmex thoracicus Gallardo, 1916 (Formicidae: Dolichoderinae), a species commonly found in urban environments and which can cause damage to human health. Bioassays of fumigation toxicity and locomotor activity in partially treated arenas were performed. The lethal concentrations to kill 50% of the D. thoracicus population ranged from 0.69 to 2.48 µL/L for EOs and from 3.75 to 1.49 µL/L for the (E)-caryophyllene and α-humulene compounds. The survival of the ants exposed to LC95 of the treatments was reduced over time, ranging from 4.2 to 35.6 h to kill 50% of the D. thoracicus population. In general, EOs of V. curassavica caused repellency and affected the locomotor activity of the ants. Our results indicate that EOs of V. curassavica are a promising source for the control of the urban ant D. thoracicus.

Natural mortality factors of tomato leafminer Tuta absoluta in open-field tomato crops in South America.

BACKGROUND: Little importance has been given to the role of natural mortality factors (biotic and abiotic) in the regulation of tomato leafminer Tuta absoluta (Lepidoptera: Gelechiidae) populations. The present study determined the action of mortality factors on T. absoluta populations infesting cultivated tomato crops. Eighty ecological life tables for T. absoluta in field cultivated tomato plants were constructed and analyzed. RESULTS: Total T. absoluta mortality was 99.08%, with 38.76% mortality during the egg phase, 57.20% in the larva phase and 3.12% in the pupal phase. The main mortality factors during the egg stage were predation, parasitism and egg inviability. In the larval stage, the main mortality factors were predation, parasitism, entomopathogenic agents and physiological disorders. In the pupal stage, the main mortality factor was predation. The larvae of the third and fourth instar were more susceptible to the action of mortality factors and the predatory wasp, Protonectarina sylveirae, was the main insect predator of these larvae. CONCLUSIONS: The T. absoluta population is regulated under field conditions by the action of natural enemies of the larvae. The predatory wasp P. sylveirae is very important in the regulation of T. absoluta populations in open-field tomato crops in Brazil. © 2018 Society of Chemical Industry.

Apis mellifera (Insecta: Hymenoptera) in the target of neonicotinoids: A one-way ticket? Bioinsecticides can be an alternative.

The recent decline of Apis mellifera populations around the world has been subject of intense research due to ecological and economic damages resulting from the loss of pollination services. The intensive use of insecticides from the neonicotinoids group is among the possible causal factors of this decline, including also sub-lethal effects. However, the use of synthetic insecticides has been increased on a global scale in the recent decades. In order to evaluate an alternative to the use of neonicotinoids, this work investigated the effects of a bioinsecticide and its major compound on A. mellifera (Apidae: Hymenoptera), one of the main pollinators of crop plants. For this, bees were exposed, by contact and ingestion, to the essential oil of Cymbopogon martinii (Poaceae: Poales), to geraniol (major compound) and the insecticide imidacloprid to evaluate the toxicity and behavioral effects as well as the locomotion changes and immune responses of bees treated with these compounds. In general, toxicity was greater through ingestion and the insecticide imidacloprid was more toxic to A. mellifera compared to the essential oil and its major compound. The individual and collective behaviors (i.e. trophallaxis, grooming, avoidance) as well as the immune responses of bees were not significantly affected by bioinsecticides. However, the locomotion response and flight orientation of the bees were significantly altered by insecticide when administered by ingestion. Our results highlight the potential of C. martinii essential oil and its major compound as a possible alternative to mitigate the harmful effects of neonicotinoids on bees.

Alternative control of Aedes aegypti resistant to pyrethroids: lethal and sublethal effects of monoterpene bioinsecticides.

BACKGROUND: The mosquito Aedes aegypti is intensively controlled because it is a vector of viruses that cause numerous diseases, especially in tropical regions. As a consequence of the indiscriminate use of insecticides, populations from different regions have become resistant to pyrethroids. Here, we analyzed the lethal and sublethal effects of essential oil of Aristolochia trilobata and its major compounds on A. aegypti from susceptible and pyrethroid-resistant populations. RESULTS: Our results showed that the toxicity of the different compounds and behavioral changes in response to them are dependent on the stage of the insect life cycle. The monoterpene ρ-cymene caused high mortality in both larvae and adult females of A. aegypti, including those from the pyrethroid-resistant population. The monoterpenes limonene and linalool caused a sublethal effect in the larvae, triggering changes in the swimming pattern. CONCLUSION: This study highlights the potential of the essential oil of A. trilobata and its major compounds ρ-cymene and limonene for the control of A. aegypti and reveals the importance of analyzing sublethal effects on the population dynamics of the A. aegypti mosquito. © 2017 Society of Chemical Industry.

Sub-lethal effects of essential oil of Lippia sidoides on drywood termite Cryptotermes brevis (Blattodea: Termitoidea).

The drywood termite Cryptotermes brevis (Walker, 1853) (Kalotermitidae) is one of the most important wood structural pest in the world. Substances from the secondary metabolism of plants (e.g., essential oils) have been considered an environmentally safer form of control for urban pests, such as termites. In the present study, we analyzed the lethal and sub-lethal effects of essential oil of Lippia sidoides and its major components on C. brevis pseudergates in two routes of exposure (contact and fumigation). The essential oil of L. sidoides and thymol were more toxic to C. brevis pseudergates when applied by contact (LD50 = 9.33 and 8.20µgmg-1, respectively) and by fumigation (LC50 = 9.10 and 23.6µLL-1, respectively). In general, treatments changed the individual and collective behaviors of C. brevis pseudergates, as well as the displacement and walking speed. The essential oil of L. sidoides and its major components showed a high potential to control C. brevis pseudergates, due to the bioactivity in the two routes of exposure and the sub-lethal effects on the behavior and walking, important activities for the cohesion of C. brevis colonies.

Essential Oils of Hyptis pectinata Chemotypes: Isolation, Binary Mixtures and Acute Toxicity on Leaf-Cutting Ants.

Leaf-cutting ants are pests of great economic importance due to the damage they cause to agricultural and forest crops. The use of organosynthetic insecticides is the main form of control of these insects. In order to develop safer technology, the objective of this work was to evaluate the formicidal activity of the essential oils of two Hyptis pectinata genotypes (chemotypes) and their major compounds on the leaf-cutting ants Acromyrmex balzani Emery and Atta sexdens rubropilosa Forel. Bioassays of exposure pathways (contact and fumigation) and binary mixtures of the major compounds were performed. The major compounds identified in the essential oils of H. pectinata were ß-caryophyllene, caryophyllene oxide and calamusenone. The essential oils of H. pectinata were toxic to the ants in both exposure pathways. Essential oils were more toxic than their major compounds alone. The chemotype calamusenone was more toxic to A. balzani in both exposure pathways. A. sexdens rubropilosa was more susceptible to the essential oil of the chemotype ß-caryophyllene in both exposure pathways. In general, the binary mixtures of the major compounds resulted in additive effect of toxicity. The essential oils of H. pectinata is a raw material of great potential for the development of new insecticides.

Essential Oil of Aristolochia trilobata: Synthesis, Routes of Exposure, Acute Toxicity, Binary Mixtures and Behavioral Effects on Leaf-Cutting Ants.

Plants of the genus Aristolochia have been frequently reported as important medicinal plants. Despite their high bioactive potential, to date, there are no reports of their effects on leaf-cutting ants. Therefore, the present study aimed to evaluate the insecticidal activity of the essential oil of Aristolochia trilobata and its major components on Atta sexdens and Acromyrmex balzani, two species of leaf-cutting ants. The bioassays were performed regarding routes of exposure, acute toxicity, binary mixtures of the major components and behavioral effects. Twenty-five components were identified in the essential oil of A. trilobata using a gas chromatographic system equipped with a mass spectrometer and a flame ionization detector. The components found in higher proportions were sulcatyl acetate, limonene, p-cymene and linalool. The essential oil of A. trilobata and its individual major components were efficient against A. balzani and A. sexdens workers when applied by fumigation. These components showed fast and efficient insecticidal activity on ants. The components acted synergistically and additively on A. balzani and A. sexdens, respectively, and caused a strong repellency/irritability in the ants. Thus, our results demonstrate the great potential of the essential oil of A. trilobata and its major components for the development of new insecticides.

Combined foraging strategies and soldier behaviour in Nasutitermes aff. coxipoensis (Blattodea: Termitoidea: Termitidae).

A range of behavioural strategies and sensory abilities allows animals to minimize costs involved in food search. By building a network of tunnels and presenting a large number of soldiers (i.e., trophically dependent individuals), Nasutitermes spp. termites feature behaviours that imply additional costs during this process. Here we evaluated N. aff. coxipoensis foraging strategies focusing on the role of soldiers during foraging. Field experiments were carried out via nests transplantation to dune areas, and laboratory experiments evaluated termite responses to sternal gland chemical signals from workers and soldiers. N. aff. coxipoensis presented primarily nocturnal foraging. Soldiers typically initiated foraging; however, in established trails, the number of workers was always higher than that of soldiers. The number of trails remained constant over time, while the number of tunnels increased linearly over time. A higher proportion of tunnels originated in surrounding areas than directly from the nests. At observation points with tunnels, there were more stationary than walking soldiers; the opposite was true at observation points without tunnels. In mixed groups, the workers chose to follow soldier chemical signals, and in these groups, soldiers were the first to follow trails. Our results allowed us to identify a not common foraging strategy in termite species; which included the establishment of trails followed by construction of tunnels. Such foraging strategies occur predominantly at night and soldiers play a key role in the foraging process. This foraging strategy reported here seems to be employed to optimize energetic gain.