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Plutella xylostella is the main pest of cruciferous crops worldwide. To reduce P. xylostella populations, better integration of natural control and chemical control (dominant tactic used) is needed. This work analyzed the compatibility of nine insecticides with the parasitoid Diadegma insulare, outlining them as complementary tools in an integrated pest management strategy. The acute toxicity of spinosad, imidacloprid, indoxacarb, flonicamid, naled, pyridalyl, emamectin benzoate, and spinetoram against the parasitoid was assessed. Residual activity (persistence) was also evaluated over time; the mortality of the parasitoid in contact with leaf tissue of plants treated with insecticides was analyzed. According to the International Organization of Biological Control, all nine insecticides were toxic to D. insulare; the lowest mortality was recorded with spirotetramat (64%) and pyridalyl (48%), while the rest of the insecticides caused 100% mortality at 72 h after application. In terms of persistence, by days 14, 16, 16, 17, 17, 21, and 22 after application, flonicamid, naled, spirotetramat, spinosad, piridalyl, imidacloprid, and indoxacarb caused mortality of less than 25%, respectively, so they were considered harmless (Category 1). Nonetheless, some insecticide toxicity and residual activity must be regarded within integrated pest management programs for conserving the role of D. insulare field populations.

RESUMO

For years, the presence of clubroot disease and its causal agent, Plasmodiophora brassicae, in Mexico has been stated as a fact. However, an intensive search of the scientific literature in English and Spanish, as well as gray literature including theses and government reports, did not reveal any information about the actual detection of the pathogen, affected hosts, or areas with clubroot presence, or any information about clubroot (hernia de la col in Mexico). We followed a multistep process to confirm whether P. brassicae was indeed in Mexico. First, we identified agricultural communities with a history of cruciferous crop cultivation. Second, we asked growers if they had seen clubroot on their crops, using pictures of the characteristic root galls. Third, we collected soil from the locations where clubroot was reported and looked for clubroot/P. brassicae in the soil using several cruciferous bait plants. For the first time we confirm the presence of the clubroot pathogen P. brassicae in Mexico, through a bioassay, the presence of resting spores, and a P. brassicae-specific PCR assay. The identification of P. brassicae in Mexico will contribute to our understanding of the genetic diversity of this elusive and devastating plant pathogen in future studies.[Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

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The increased use of pesticides applied to treat diseases caused by bacteria has caused serious environmental problems. There are few fungicides/bactericides for the treatment of plant diseases caused by Xanthomonas campestris pv. campestris (Xcc), and only two natural products with general bactericidal/fungicidal use are available on the market. Thus, this study evaluated the antimicrobial activity of essential oils (EOs), and their combinations, from five distinct genotypes of Cordia curassavica (Jacq.) Roem. & Schult (Syn. Varronia curassavica Jacq.) (CCUR) against Xcc. GC/MS chemical analysis revealed α-pinene, sabinene, (E)-caryophyllene, ar-curcumene, ß-sesquiphellandrene, 7-cyclodecen-1-one, and ar-Turmerone as the major compounds of the five EOs of CCUR. All EOs showed growth inhibition of Xcc with minimum inhibitory concentration between 500 and 1000 µg mL-1. The associations between two EOs from different CCUR genotypes showed that 70% of the total combinations had an additive effect. However, the combinations between CCUR-002 × (-302, -202) and CCUR-302 × (-601) showed a synergistic effect, with mean fractional inhibitory concentration FIC50 values of 0.28, 0.42, and 0.40, respectively. This study demonstrates that combinations of C. curassavica EOs have antimicrobial activity and a potential to be used in the control of black rot. Graphical abstract.

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Xanthomonas campestris pv.campestris (Xcc) is the causative agent of black rot, a disease that causes serious damage to plants from Brassicaceae family. However, there are no chemicals or biological agent commercially registered for the control of this disease. Thus, this study aimed to evaluate the antimicrobial activity and chemical composition of Lippia gracilis essential oils (EOs) on Xcc aiming its use as effective biological control. We also investigated the effect of EOs on the integrity of the bacterial cytoplasmic membrane. Chemical analysis by GC/MS showed that the major compounds of the seven EOs of L. gracilis are thymol or carvacrol. The seven genotypes showed inhibition of bacterial growth with MIC from 700 µg.ml-1 to 1000 µg.ml-1, with the genotype LGRA-106 (rich in Thymol) with higher antimicrobial activity. The MIC for thymol and carvacrol were 250 µg.ml-1. After exposure to LGRA-106 EO (2×, 1×, 1/2×, 1/4×, and 1/8 x MIC for 5 min, it was observed a decreased cell viability and increased pI fluorescence, which indicates damage to the cytoplasmic cell membrane. This study demonstrates that L. gracilis EOs have antimicrobial activity and have a potential to be used in the control of black rot. Furthermore this antimicrobial activity is due, at least in part, to bacterial cytoplasmic membrane damage.

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This study aimed the development of nanocapsules (NCs) for oral indole-3-carbinol (I3C) administration and evaluation of antinociceptive potential of this compound in its two forms, free and nanoencapsulated, using acute pain models. NCs showed adequate physicochemical characteristics and protected the I3C against UVC radiation exposure. It was observed no chemical bond between I3C and polymer by FTIR. Besides, X-ray and DSC analysis suggested that I3C was molecularly dispersed in NCs. The dialysis bag technique showed that almost 100% of the compound was released from NCs at 360min. Mathematical modeling demonstrated that this release occurred in two rates, with an initial burst effect followed by a slower release of I3C. Regarding the in vivo analysis, time-response curve showed that both forms of I3C caused an inhibition in inflammatory phase of nociception induced by formalin and increased the latency response in hot plate test. Interestingly, NCs were able to prolong the I3C effect in both tests. Furthermore, in dose-response curve, only I3C in its nanoencapsulated form presented effect on inflammatory phase of the formalin test. In conclusion, NCs to I3C incorporation presented adequate nanometric characteristics and prolonged its antinociceptive action in acute pain models tested.

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A estimativa da área foliar, em função da sua redução causada pelo consumo por insetos filófagos, é uma metodologia básica em várias áreas da Entomologia, como, por exemplo, em estudos sobre resistência de plantas, entomologia econômica e ecologia nutricional. Um dos fatores que pode interferir na quantidade de área foliar consumida pelo fitófago é a presença de certos químicos nas folhas, como a sinigrina em brassicáceas. Dessa forma, foram aplicadas em folhas de couve e brócolis diversas concentrações de sinigrina (0,2, 0,4, 0,8, 1,6, e 3,2 mg/mL em solução a 5% de Tween20(r)), medindo-se o consumo da área foliar por lagartas de P. xylostella, o qual foi aferido pela porcentagem de redução da área, diferença de peso e escala visual de notas. Os resultados mostraram que as concentrações 0,2, 0,4 e 3,2 mg/mL de sinigrina aumentam o consumo em folhas de couve e diminuem em folhas de brócolis por lagartas de P. xylostella. As metodologias utilizadas proporcionam resultados similares, sendo as estimativas de peso fresco e nota visual mais práticas.(AU)

Leaf area estimation, based on their reduction due to consumption by phytophagous insects, is a basic methodology in several areas of Entomology, for instance, in studies about plant resistance, economic entomology and nutritional ecology. One of the factors that can affect the amount of leaf area consumed by insects is the presence of certain chemicals in the leaves, such as sinigrin in Brassicaceae. Thus, several concentrations of sinigrin were applied on the leaves of cabbage and broccoli (0.2, 0.4, 0.8, 1.6, and 3.2 mg/mL in 5% Tween20(r) solution) in order to measure leaf area consumption by larvae of P. xylostella, estimated by the percentage of area reduction, weight loss and visual scale of notes. The results show that the concentrations of 0.2, 0.4 and 3.2 mg/mL of sinigrin increase larvae consumption of P. xylostella on kale leaves and decrease it on broccoli leaves. The methodologies used provide similar results, and fresh weight measurements and visual grades are more practical.(AU)

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A estimativa da área foliar, em função da sua redução causada pelo consumo por insetos filófagos, é uma metodologia básica em várias áreas da Entomologia, como, por exemplo, em estudos sobre resistência de plantas, entomologia econômica e ecologia nutricional. Um dos fatores que pode interferir na quantidade de área foliar consumida pelo fitófago é a presença de certos químicos nas folhas, como a sinigrina em brassicáceas. Dessa forma, foram aplicadas em folhas de couve e brócolis diversas concentrações de sinigrina (0,2, 0,4, 0,8, 1,6, e 3,2 mg/mL em solução a 5% de Tween20(r)), medindo-se o consumo da área foliar por lagartas de P. xylostella, o qual foi aferido pela porcentagem de redução da área, diferença de peso e escala visual de notas. Os resultados mostraram que as concentrações 0,2, 0,4 e 3,2 mg/mL de sinigrina aumentam o consumo em folhas de couve e diminuem em folhas de brócolis por lagartas de P. xylostella. As metodologias utilizadas proporcionam resultados similares, sendo as estimativas de peso fresco e nota visual mais práticas.(AU)

Leaf area estimation, based on their reduction due to consumption by phytophagous insects, is a basic methodology in several areas of Entomology, for instance, in studies about plant resistance, economic entomology and nutritional ecology. One of the factors that can affect the amount of leaf area consumed by insects is the presence of certain chemicals in the leaves, such as sinigrin in Brassicaceae. Thus, several concentrations of sinigrin were applied on the leaves of cabbage and broccoli (0.2, 0.4, 0.8, 1.6, and 3.2 mg/mL in 5% Tween20(r) solution) in order to measure leaf area consumption by larvae of P. xylostella, estimated by the percentage of area reduction, weight loss and visual scale of notes. The results show that the concentrations of 0.2, 0.4 and 3.2 mg/mL of sinigrin increase larvae consumption of P. xylostella on kale leaves and decrease it on broccoli leaves. The methodologies used provide similar results, and fresh weight measurements and visual grades are more practical.(AU)

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Objetivou-se avaliar a interação tritrófica no complexo hospedeiro-vegetal (brássicas) x praga/hospedeiro-natural Plutella xylostella Linnaeus x inseto-entomófago (parasitóides - Trichogrmma pretiosum Riley e T. exiguum Pinto & Platner), associada a alguns produtos químicos e vegetais com efeito inseticida, utilizando-se os cultivares de repolho verde - Chato de quintal e híbrido Midori; roxo - Roxo precoce e Híbrido roxo - TPC00682; e couve manteiga - Geórgia e hibrido Geórgia HS20, pulverizadas com os inseticidas: lufenuron (2,52 ml/100L) e deltametrina (32 ml/100L), os produtos vegetais óleo de nim a 0,16 por cento e extrato pirolenhoso a 3,0 por cento, controle (água). Foi avaliada a interação das cultivares com os compostos por meio da exposição de lagartas recém-eclodidas aos produtos, avaliando-se os insetos nas fases de desenvolvimento até a emergência dos adultos. Para avaliar o efeito desses compostos sobre os parasitóides, foram empregados ovos de uma geração F2 de P. xylostella oriunda de lagartas alimentadas com folhas de brássicas, pulverizadas com esses produtos. A associação de produtos químicos ou vegetais, com efeito inseticida, com as cultivares de brássicas permitiu o manejo mais eficaz, especialmente na interação extrato pirolenhoso x a cultivar de repolho Chato de quintal. Observa-se que a interação entre as cultivares e os produtos pode ser prejudicial à atuação do parasitóide Trichogramma, sendo necessária uma avaliação criteriosa para minimizar o efeito sobre inimigos naturais.

The aim of this work was to evaluate the tritrofic interaction in brassica complex: host-vegetable (brassica) vs. pest/natural-host (Plutella xylostella) vs. entomophagous-insect (parasitoid - Trichogramma pretiosum and Trichogramma exiguum), combined with chemical and vegetable products with insecticide action. The cultivar used were: green cabbage - Chato de quintal and Midori hybrid; purple cabbage - Roxo Precoce and purple hybrid - TPC00682; kale - Georgia and Georgia hybrid HS20. They were sprayed using the insecticides - lufenuron (2,52 ml/100L) and deltamethrin (32 ml/100L); the vegetal products - neen oil (0,16 percent) and pyroligneous extract (3,0 percent); and water (check). The cultivars interaction was evaluated with the products, by larvae exposition to the treatments, being analyzed the different phases of development through adults emergence. To evaluate the effect of these products on the parasitoids, P. xylostella, eggs from F2 generation were used. Eggs of this pest were collected from adults fed with brassica leaves that were sprayed with the mentioned products. The insecticides association and vegetable products combined with brassica cultivars became more effective to manage the pest control, especially in the pyroligneous extract x Chato de Quintal interaction. The interaction between the cultivars and products may be harmful to Trichogramma performance being necessary a discerning evaluation to minimize the effect on natural enemies.