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.

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.

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.

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 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.

Acaricidal properties of vetiver essential oil from Chrysopogon zizanioides (Poaceae) against the tick species Amblyomma cajennense and Rhipicephalus (Boophilus) microplus (Acari: Ixodidae).

Ticks are arthropods widely distributed in tropical and subtropical regions, which can transmit infectious agents also responsible for zoonoses. Excessive use of conventional acaricides has resulted in the onset of drug resistance by these parasites, thus the need to use alternative methods for their control. This study evaluated the acaricidal activities of Chrysopogon zizanioides (vetiver) essential oils containing different zizanoic and khuzimol (high and low acidity) acid concentrations on Amblyomma cajennense and Rhipicephalus microplus (Acari: Ixodidae). To this aims, toxicity tests of different concentrations of examined essential oils were conducted on adult females and larval stages. Results showed that the essential oils of C. zizanioides with high and low acidity reduced oviposition of females, eggs hatch and larval survival, being more effective than some commercial products widely used to control these ectoparasites. These results indicate that the C. zizanoides essential oils are promising candidates as acaricidal agents and represent also an add value to vetiver oil with high acidity, which is commercially undervalued in the cosmetic industry.

Acaricidal activity of essential oils from Lippia alba genotypes and its major components carvone, limonene, and citral against Rhipicephalus microplus.

The goal of the present study was to evaluate the acaricidal potential of Lippia alba essential oil, citral chemotypes (LA-10 and LA-44 genotypes) and carvone chemotypes (LA-13 and LA-57 genotypes), as well as purified citral and enantiomers of carvone and limonene. Efficacy against Rhipicephalus microplus was assessed by the larval packet and the engorged female immersion tests. Citral chemotypes had greater larvicidal activity than carvone chemotypes, and this was further supported by larvicidal and adulticidal activity of purified citral with LC50 values of 7.0 and 29.8 mg/mL, respectively. While purified enantiomers of carvone exhibited greater larvicidal activity than those of limonene, enantioselectivity of limonene was observed with R-(+) displaying significantly higher efficacy (LC50 of 31.2mg/mL) than S-(-) (LC50 of 54.5mg/mL). The essential oils and purified compounds were much less toxic toward engorged adult females, with the exception of citral, and this may be due to limited cuticular penetration.

Water deficit and seasonality study on essential oil constituents of Lippia gracilis Schauer germplasm.

The aim of this study was to analyze the chemical composition of the essential oil from leaves of Lippia gracilis genotypes, in the dry and rainy seasons, and with and without irrigation. The extraction of essential oil was realized by hydrodistillation in a Clevenger apparatus. The chemical composition analysis was performed using a GC-MS/FID. The leaves of the L. gracilis genotypes provide essential oil with content between 1.25% and 1.92% in the rainy season and 1.42% and 2.70% in the dry season; when irrigation was used the content was between 1.42% and 2.87%, without irrigation contents were between 1.60% and 3.00%. The chemical composition of L. gracilis showed high levels of terpenes. The major constituent of genotypes LGRA-106 was thymol and carvacrol was the major constituent for the other genotypes. Concentrations showed little variation between seasons, demonstrating the stability of the chemical composition of L. gracilis even with different climatic conditions.

Insecticidal and repellence activity of the essential oil of Pogostemon cablin against urban ants species.

Ants are highly abundant in neotropical regions, with certain species adapted to the urban environment, where they can cause damage to human health. The main method for controlling ants consists of using organosynthetic insecticides, which are potentially toxic to the environment. Essential plant oils are considered a viable alternative to the use of conventional insecticides. In this study, we analyze the bioinsecticidal activity and repellence of patchouli essential oil (Pogostemon cablin) against three species of urban ants: Camponotus melanoticus, Camponotus novograndensis, and Dorymyrmex thoracicus. The chemical composition of the essential oil was analyzed by GC-MS and GC-FID. The major compounds were patchoulol (36.6%) followed by α-bulnesene (13.95%), and α-guaiene (11.96%). Toxicity and repellency bioassays were performed using the essential oil over the ants, and mortality evaluations were performed at 4, 24, and 48 h after performing the bioassays. Mortality percentage of the ants on 7 µg/mg was on average 84%. The essential oil of P. cablin displayed toxicity against all three species of urban ants, with the lowest LD50 being observed for D. thoracicus (2.02 µg oil/mg insect) after 48 h of exposure compared to C. melanoticus (2.34 µg oil/mg insect) and C. novogranadensis (2.95 µg oil/mg insect). The essential oil of P. cablin was strongly repellent to the three species of ants in all concentrations tested (0.01% and 1% v/v). Considering the potential toxicity and repellency of the P. cablin essential oil to the urban ants, future studies could investigate the practical application of this oil to control of this insects.

Acaricidal activity of Lippia gracilis essential oil and its major constituents on the tick Rhipicephalus (Boophilus) microplus.

The present study aimed to evaluate the activity of Lippia gracilis Schauer essential oil obtained from different L. gracilis genotypes and their major components, carvacrol and thymol against Rhipicephalus (Boophilus) microplus (cattle tick) larvae and engorged females. The larval test was performed parallel to the adult immersion test for engorged females for four L. gracilis genotypes. Similar tests were further performed for their major compounds carvacrol and thymol. Carvacrol (LC50 of 0.22 and 4.46 mg/mL, to larvae and engorged females, respectively) was more efficient than thymol (LC50 of 3.86 and 5.50 mg/mL, to larvae and engorged females, respectively). The lethal concentrations obtained for the isolated essential oil from genotypes LGRA-201 against larvae (1.31 mg/mL) and LGRA-106 against engorged females (4.66 mg/mL) confirmed the acaricidal activity of L. gracilis essential oil and its effectiveness in controlling the southern cattle tick.