To discover new bisamide compounds with insecticidal and fungicidal activities, 19 novel cyproflanilide derivatives containing 1,2,4-oxadiazole group were designed and synthesized according to the principle of biologically active factor splicing. Preliminary biological assay data indicated that the majority of target compounds demonstrated significant insecticidal activity against Lepidopteran pests. Meanwhile, compounds 5p and 5q showed 97.22 and 100% lethality against Tetranychus cinnabarinus at 400 mg L-1, which were better than cyproflanilide (41.11% at 400 mg L-1). In addition, it is exciting that we have achieved our initial goals as some of the target compounds exhibited both insecticidal and fungicidal activities. For instance, compounds 5b and 5c showed 59.26 and 74.07% fungicidal activities against Cucumber downy mildew at 400 mg L-1, as well as 100% insecticidal activity against Plutella xylostella and armyworm at 100 mg L-1. Compound 5h showed 100% insecticidal activity against armyworm at 10 mg L-1, and also displayed 66.67% fungicidal activity against Cucumber downy mildew at 400 mg L-1. The inhibition rate of compounds 5l and 5s against Cucumber downy mildew reached 88.89 and 96.30% at 400 mg L-1. This work showed the effectively fungicidal application of 1,2,4-oxadiazole group in bisamide compounds and provides insights for optimal structural design. 1 1,2,4oxadiazole 124oxadiazole oxadiazole 1,2,4 2 4 splicing pests Meanwhile p q 9722 97 22 97.2 40 L1, L1 L 1, L-1 41.11% 4111 41 11 (41.11 L1. . L-1) addition instance b c 5926 59 26 59.2 7407 74 07 74.07 1. h 6667 66 67 66.67 l s 8889 88 89 88.8 9630 96 30 96.30 design 4oxadiazole 124 1,2, 972 9 97. L- 41.11 411 (41.1 592 5 59. 740 7 0 74.0 666 6 66.6 888 8 88. 963 3 96.3 12 1,2 41.1 (41. 74. 66. 96. 41. (41 (4 (

ABSTRACT Plutella xylostella is one of the most important pests of brassicaceous crops around the world. Indoxacarb is widely used to control lepidopteran pest larvae. This insecticide has slow activity and prolonged residual effects which impact the habits and physiology of pests. The objective was to evaluate the effect of sublethal concentrations of indoxacarb on the biology and development time of the diamondback moth. Selection pressure of the insecticide indoxacarb was carried out on P. xylostella, applying the LC20 of the previous generation for the next ten generations, the LC20 of the resistant line (G10) was calculated and this concentration was subsequently applied to L3 larvae. The effect on the percentage and weight of pupae, adult emergence and oviposition for two generations was evaluated; in addition, the development time of egg, larva, pupa and adult. The results showed that resistance and exposure to LC20 of indoxacarb caused changes in the biology and development of P. xyllostella. This was manifested in an increase in the percentage and weight of formed pupae and emergence of adults, along with a prolongation of development time of more than 10 days. However, a decrease of more than 50% in the number of eggs per female was observed.

RESUMEN Plutella xylostella es una plaga de las más importantes en los cultivos de brassicaceas alrededor del mundo. El indoxacarb se utiliza ampliamente para el control de larvas de lepidópteros plaga. Este insecticida presenta una actividad lenta y efectos residuales prolongados los cuales impactan los hábitos y la fisiología de las plagas. Como objetivo se estableció la evaluación del efecto de concentraciones subletales de indoxacarb en la biología y tiempo de desarrollo de la palomilla dorso de diamante. Se realizó presión de selección del insecticida indoxacarb sobre P. xylostella, aplicando la CL20 de la generación anterior por las siguientes diez generaciones, se calculó la CL20 de la línea resistente (G10) y posteriormente se aplicó esta concentración a larvas de L3. Se evaluó el efecto en el porcentaje y peso de pupas, emergencia de adultos y oviposición para dos generaciones; además, del tiempo de desarrollo de huevo, larva, pupa y adulto. Los resultados mostraron que la resistencia y la exposición a CL20 de indoxacarb provocaron cambios en la biología y el desarrollo de P. xyllostella. Esto se manifestó en un aumento del porcentaje y peso de pupas formadas y emergencia de adultos, junto con una prolongación del tiempo de desarrollo de más de 10 días. Sin embargo, se observó una disminución de más del 50% en el número de huevos por hembra.

This work is based on the precursor compound cyproflanilide and designs a series of methoxy containing meta-diamine compounds. By replacing the fluorine atom on the phenyl ring in cyproflanilide with methoxy group, 17 derivatives (12a-12q) were obtained with yields ranging from 46 to 92%, which were characterized by high-resolution mass spectrometry, and nuclear magnetic resonance (1H and 13C) spectroscopy and infrared. The insecticidal activities were evaluated against the Plutella xylostella and Spodoptera frugiperda. Compound N-(3-((2-bromopropane-4-(perfluoropropan-2-yl))-6-(trifluoromethyl)phenyl)methoxyphenyl)-N-(cyclopropylmethyl)-6-fluoronicotinamide (12q) showed significant insecticidal activity against the Plutella xylostella with a mortality rate of 97.67% at a concentration of 1 mg L-1. It also exhibited moderate activity against the Spodoptera frugiperda at a concentration of 0.1 mg L-1, which can be used as a template for structure modification to obtain higher insecticidal activity. metadiamine meta diamine compounds group 12a12q aq 12a 12q q (12a-12q 4 92 92% highresolution high resolution spectrometry 1H H 13C C infrared N32bromopropane4perfluoropropan2yl6trifluoromethylphenylmethoxyphenylNcyclopropylmethyl6fluoronicotinamide NbromopropaneperfluoropropanyltrifluoromethylphenylmethoxyphenylNcyclopropylmethylfluoronicotinamide N 3 2 bromopropane perfluoropropan yl 6 trifluoromethyl methoxyphenyl cyclopropylmethyl fluoronicotinamide (12q 9767 97 67 97.67 L1. L1 L 1. L-1 01 0 0. L1, 1, 9 trifluoromethylphenylmethoxyphenylNcyclopropylmethyl 976 97.6 L- 97.

Abstract The objective of this study was to characterize cabbage production systems in four rural cooperatives in Jinotega, with emphasis on socioeconomic, agronomic, and phytosanitary aspects. A prospective, cross-sectional, non-experimental study was carried out, 60 production systems were evaluated, the information obtained proceeding from primary sources (surveys and interviews), the variables were subjected to a descriptive analysis. The age of the producers was in the range of 20 to 80 years, their main economic activity is agriculture, with levels of initial literacy levels, housing conditions are in the range of fair to good, the cultivated area ranges between 0,34 to 5,0 hectares, they have training, the main crop management practices were: weed management, soil preparation, use of traps, monitoring of pests and diseases, use of certified seeds, use of resistant varieties, stubble management and irrigation. The main diseases are: Rhizoctonia spp Xanthomonas spp, Alternaria spp and Mycosphaerella spp and insect pests Plutella xylostella L, Brevicoryne spp and Mites. All controlled through synthetic chemical management.

Resumen El presente estudio tuvo como objetivo caracterizar sistemas productivos de repollo en cuatro cooperativas rurales en Jinotega, con énfasis en aspectos socioeconómicos, agronómicos y fitosanitarios. Se realizó un estudio prospectivo, transversal de tipo no experimental, se evaluaron 60 sistemas de producción, la información obtenida fue de fuentes primarias (encuestas y entrevistas), las variables fueron sometidas a un análisis descriptivo. La edad de los productores estuvo en un rango de 20 a 80 años, su principal actividad económica es la agricultura, con niveles de educación inicial, las condiciones de la vivienda están en el rango de regular a buena, el área cultivada oscila entre 0,34 a 5,0 ha, cuentan con capacitación, las principales prácticas de manejo del cultivo fueron: manejo de arvenses, preparación del suelo, uso de trampas, monitoreo de plagas y enfermedades, uso de semillas certificadas, variedades resistentes, manejo de rastrojo y riego. Las principales enfermedades son: Rhizoctonia spp, Xanthomonas spp, Alternaria spp y Mycosphaerella spp y plagas insectiles Plutella xylostella L. Brevicoryne spp y ácaros. Todas controladas mediante el manejo químico sintético.

ABSTRACT Plutella xylostella cause severe damage on cruciferous plants all over the world. Farmers in several regions of Brazil report increasing inefficiency of chemical control, even when using high insecticide concentrations. We evaluate here the susceptibility of brazilian diamondback moth populations to the Premio® (Chlorantraniliprole), Dipel® (Bacillus thuringiensis var. kurstaki) and Lannate® BR (Oxime Methylcarbamate) insecticides, frequently used in Brazil. Susceptibility bioassays with five field-collected and two laboratory diamondback moth populations were conducted with increasing concentrations of insecticides up to ten times above the recommended concentration. Extremely high and region-dependent resistances were found in field populations against Chlorantraniliprole and B. thuringiensis, with Resistance Ratios up to 370.0 times for the Camocim de São Felix population. For Oxime Methylcarbamate, we were not able to do Probit analyses for the field populations because of very low mortality rates. Laboratory populations showed resistance to the three tested insecticides with all LC50 concentrations exceeding the recommended doses by at least 3 times. Our results show strong and variable resistance to the three tested insecticides according to the region of origin. To maintain efficient pest control in a large country like Brazil, local levels of resistance need therefore to be monitored by the authorities and reassessment and adjustments of regional doses of insecticides should be implemented as a public policy, to prevent massive spread of insecticides in the field, as well as increases in cases of resistance. world Premio Chlorantraniliprole, , (Chlorantraniliprole) Dipel Bacillus var kurstaki Lannate Methylcarbamate fieldcollected collected concentration regiondependent dependent B 3700 370 0 370. population rates LC LC5 origin policy (Chlorantraniliprole 37

RESUMO Plutella xylostella causa graves danos em plantas crucíferas em todo o mundo. Agricultores em várias regiões do Brasil relatam uma crescente ineficiência no controle químico, mesmo com o uso de altas concentrações de inseticidas. O objetivo deste trabalho foi avaliar a suscetibilidade de populações brasileiras da traça-das-crucíferas aos inseticidas Premio® (Chlorantraniliprole), Dipel® (Bacillus thuringiensis var. kurstaki) e Lannate® BR (Metilcarbamato de oxina), frequentemente usados no Brasil. Os bioensaios de suscetibilidade foram realizados com cinco populações de traça-das-crucíferas coletadas em campo e duas de laboratório e foram conduzidos com concentrações crescentes de inseticidas até dez vezes acima da concentração recomendada. Resistências extremamente altas e dependentes da região foram encontradas em populações de campo para o Chlorantraniliprole e B. thuringiensis, com Razões de Resistência de até 370,0 vezes para a população de Camocin de São Felix . Para Metilcarbamato de oxina, não foi possível realizar a análise Probit para as populações de campo devido baixa mortalidade. Populações de laboratório demonstraram resistência aos três inseticidas testados com concentrações de CL50 excedendo as doses recomendadas em pelo menos 3,0 vezes. Os resultados demonstraram resistência forte e variável aos três inseticidas testados de acordo com a região de origem. Para manter o controle de pragas eficiente em um país grande como o Brasil, os níveis locais de resistência precisam ser monitorados pelas autoridades e reavaliações e ajustes de doses regionais dos inseticidas deveriam ser implementadas como política pública para evitar a disseminação massiva de inseticidas em campo, assim como, aumentos dos casos de resistência. mundo químico traçadascrucíferas traça das Premio Chlorantraniliprole, , (Chlorantraniliprole) Dipel Bacillus var kurstaki Lannate oxina oxina) recomendada B 3700 370 0 370, mortalidade CL CL5 30 3 3, origem (Chlorantraniliprole 37

Abstract Known as the diamondback moth, Plutella xylostella L. is registered as one of the most important pests of Brassicaceae in the world. It is characterized as a specialized insect in this family, due to specifics for feeding. However, based on reports from producers, the shoots of sour passion fruit in the extreme south of Santa Catarina, were damaged by a phytophagous insect attack. The damage plants were collected and from this, it was possible to identify the specie P. xylostella as the insect causing the damage. Therefore, the purpose is to communicate a new record of phytophagous insect associated with passion fruit, as well as a new host outside the list of Brassicaceae for P. xylostella. The collected shoots had amber exudation and sawdust appearance in the axils of leaf growth, the plants had wilted leaves and emission of lateral shoots. It is believed that the individuals have managed to complete the life cycle in the plant because of the similarity in the nitrogen compounds present in the species of Brassicaceae and Passifloraceae. moth L world family feeding However producers Catarina attack P Therefore growth Passifloraceae

Resumo Conhecida como traça-das-crucíferas, a Plutella xylostella L. é registrada como uma das mais importantes pragas de Brassicaceae no mundo. É caracterizada como um inseto especializado nesta família, devido a especificidades para a alimentação. No entanto, após relatos de produtores de maracujazeiro-azedo, no extremo sul de Santa Catarina, de ponteiras da planta danificadas por ataque de inseto fitófago, foram realizadas coletas deste material e, a partir deste, foi possível identificar a espécie P. xylostella como o inseto causador do dano. Dessa forma, objetiva-se comunicar um novo registro de inseto fitófago associado ao maracujazeiro, assim como um novo hospedeiro fora do rol de brassicáceas para P. xylostella. As ponteiras coletadas apresentavam exsudação cor âmbar, e aspecto de serragem nas axilas de crescimento foliar, folhas murchas e a emissão de brotações laterais. Acredita-se que os indivíduos tenham conseguido completar o ciclo de vida na planta devido à semelhança nos compostos nitrogenados presentes nas espécies de Brassicaceae e de Passifloraceae. traçadascrucíferas, traçadascrucíferas traça crucíferas, crucíferas traça-das-crucíferas L mundo família alimentação entanto maracujazeiroazedo, maracujazeiroazedo maracujazeiro azedo, azedo maracujazeiro-azedo Catarina P dano forma objetivase objetiva se âmbar foliar laterais Acreditase Acredita Passifloraceae

Abstract Brown lacewings have a cosmopolitan distribution and stand out for their entomophagous habits on small, soft-bodied prey. In Mexico, the species Sympherobius barberi (Banks, 1903) is recorded from Baja California, Estado de Mexico, Guanajuato, and Morelos. Interest in its potential commercial use as a biological control agent in the country motivated the review of this species. Both in scientific publications and in databases and biological collections, the taxonomic characters required to determine this species are documented, proposing to replace the basic taxonomy based on wing spot patterns. In addition, new information on prey and host plants is recorded: Brevicoryne brassicae (Linnaeus, 1758) in Brassica spp.; Dactylopius confusus (Cockerell, 1893) in various species of Opuntia y Nopalea cochenillifera; Dactylopius opuntiae in Opuntia ficus-indica; Phenacoccus solenopsis Tinsley, 1898 in cotton; Planococcus ficus Signoret, 1875 in grapevine; and larvae of Plutella xylostella (Linnaeus, 1758) in broccoli.

Resumen Los hemeróbidos tienen una distribución cosmopolita y destacan por sus hábitos entomófagos sobre insectos pequeños de cuerpo blando. En México, la especie Sympherobius barberi (Banks, 1903) se registra en Baja California, Estado de México Guanajuato, y Morelos. El interés sobre su potencial uso comercial como agente de control biológico en el país motivó la revisión de esta especie. Tanto en publicaciones científicas como en bases de datos y colecciones biológicas, se documentan los caracteres taxonómicos requeridos para determinar esta especie y se propone sustituir la taxonomía básica basada en patrones de manchas alares. Además, se reporta nueva información sobre presas y plantas hospederas: Brevicoryne brassicae (Linnaeus, 1758) en Brassica spp.; Dactylopius confusus (Cockerell, 1893) en varias especies del género Opuntia y Nopalea cochenillifera; Dactylopius opuntiae (Cockerell, 1896) sobre Opuntia ficus-indica; Phenacoccus solenopsis Tinsley, 1898 en algodón; Planococcus ficus Signoret, 1875 en vid; y larvas de Plutella xylostella (Linnaeus, 1758) en brócoli.

Plutella xylostella cause considerable harm to the production of broccoli, Chinese cabbage, cabbage and cauliflower. The control of P. xylostella is mainly performed using commercial insecticides, which have even led to the emergence of resistant populations. Two easily available natural products found in different plants essential oil, thymol and eugenol, stand up as possible novel agents to control this pest. In this work a series of alkylated and acylated derivatives of eugenol and thymol were synthesized and screened for antifeedant, larvicidal and ovicidal activities against P. xylostella. The results of biological activities assays suggest that the novel 1,1’-[1,8-octanediylbis(oxy)]-bis(4-allyl-2-methoxy-benzene) (5) was the most toxic in the larvicidal test. Compounds 1-butoxy-2-isopropyl-5-methyl-benzene (8) and hexanedioic acid 1,6-bis(2-isopropyl-5-methyl-phenyl)-ester (10) were the most toxic in the ovicidal assay. The compound 8 presented the most antifeedant activity. Most of the compounds obtained were more active than commercially available insecticidal deltamethrin and azadirachtin.

Abstract Plutella xylostella (L.) is responsible for considerable vegetable crop losses in the metropolitan region of Manaus, Brazil. In recent decades, essential oils have been investigated as an alternative to synthetic insecticides. The genusPiperis widely distributed in Amazonia and essential oils from these plants have insecticidal properties. This study describes the chemical composition of the essential oils fromPiper capiterianumandPiper krukoffiias well as the lethal and sublethal effects onP. xylostella. The phytotoxicity of the oils on the host plant was also evaluated. Globulol was the major constituent of theP. krukoffiioil ando-cymene was the major constituent of theP. capitarianumoil. The oil fromP. capiterianumexhibited greater toxicity to larvae and eggs. This oil also presented greater repellant action, feeding deterrence and mild phytotoxicity to the host plant (Brassicae oleraceae). The findings suggest that this oil can be used in the preparation of a formulated insecticide for the management ofP. xylostellain different development phases. However, further studies are needed to evaluate the effect of this oil on crops under field conditions as well as non-target organisms and determine the cost-benefit ratio of a product formulated withP. capitarianumoil.

Resumo Os parasitoides controlam os insetos pragas, mas o seu número por hospedeiro afeta a sua eficiência. O objetivo deste trabalho foi avaliar a melhor densidade de Tetrastichus howardi (Olliff, 1893) (Hymenoptera: Eulophidae) parasitando o quarto instar de larvas de Plutella xylostella (Linnaeus, 1758) (Lepidoptera: Plutellidae) em condições de estufa. Estas lagartas foram expostas ao parasitismo por fêmeas T. howardi com densidades 1:1, 3:1, 6:1, 9:1, 12:1, 15:1 e 18:1 de parasitoide/hospedeiro com 10 repetições durante 96 horas. Após este período, as lagartas foram mantidas em plantas hospedeiras (Brassica oleracea) até à formação de pupas. Tetrastichus howardi parasitaram e reproduziram em lagartas P. xylostella em todas as suas densidades testadas, mas com valores mais elevados de 84% e 10 ± 2.4 indivíduos, respectivamente, com 9:1 parasitoides/hospedeiro. Nove fêmeas de T. howardi por lagarta de P. xylostella são o número adequado para controlar está praga de inseto.

Abstract Parasitoids control insect pests, but their number per host affects their efficiency. The objective of this work was to evaluate the best density of Tetrastichus howardi (Olliff, 1893) (Hymenoptera: Eulophidae) individuals parasitizing fourth instar Plutella xylostella (Linnaeus, 1758) (Lepidoptera: Plutellidae) larvae in greenhouse conditions. These larvae were exposed to parasitism by T. howardi females with 1:1, 3:1, 6:1, 9:1, 12:1, 15:1 and 18:1 parasitoid/host ratios with 10 replications during 96 hours. After this period the larvae were kept on host plants (Brassica oleracea) until pupa formation. Tetrastichus howardi parasitized and reproduced in P. xylostella larvae at all its densities tested, but with higher values, 84% and 10 ± 2.4 individuals, respectively, with 9:1 parasitoids/host. Nine T. howardi females per P. xylostella larvae are the adequate number to manage this insect pest.

Resumo O alto índice de consumo de hortaliças estimula o cultivo e aumenta a demanda quanto à adequação dos processos produtivos. O ataque da praga Plutella xylostella causa grandes perdas por reduzir a qualidade do produto, caracterizando um problema fitossanitário. Este trabalho teve como objetivo verificar a bioatividade de extratos aquosos de folhas de Jacaranda decurrens e Jacaranda mimosifolia nas concentrações de 5, 10 e 15% sobre o inseto. O teste de escolha foi realizado em laboratório para determinar o efeito alimentar de extratos vegetais e avaliar alterações no ciclo de vida de insetos expostos a compostos ativos por meio da análise de parâmetros biológicos. Os extratos vegetais de J. decurrens e J. mimosifolia apresentaram classificação fagodeterrente nos experimentos de escolha. As três concentrações de extrato de J. decurrens promoveram um prolongamento da duração larval e pupal, enquanto a duração dos indivíduos tratados com J. mimosifolia a 10% foi significativamente reduzida. Ocorreu redução na sobrevivência larval de indivíduos tratados com extratos aquosos de J. decurrens e J. mimosifolia. Ovos dos tratamentos com extrato aquoso de J. decurrens e J. mimosifolia tiveram sobrevivência reduzida. A sobrevivência pupal dos indivíduos tratados com extrato a 15% apresentou redução significativa em relação aos tratamentos a 5% e 10%. Pupas do tratamento com extrato aquoso de J. mimosifolia apresentaram redução de biomassa no tratamento a 15% diferindo do controle e 5%. Assim, os extratos aquosos das espécies J. decurrens e J. mimosifolia apresentam potencial inseticida nos testes realizados em P. xylostella.

Abstract The high consumption rate of vegetables stimulates the cultivation and increases the demand regarding the adequacy of the production processes. The attack of the pest Plutella xylostella causes high losses by reducing product quality, typifying a phytosanitary problem. This study aimed to verify the bioactivity of aqueous extracts of leaves of Jacaranda decurrens and Jacaranda mimosifolia at concentrations of 5, 10, and 15% on the insect. The choice test was carried out at the laboratory to determine the food effect of plant extracts and evaluate changes in the life cycle of insects exposed to active compounds through the analysis of biological parameters. Plant extracts of J. decurrens and J. mimosifolia presented with phagodeterrent classification in the choice experiments. The three J. decurrens extract concentrations promoted a prolongation of larval and pupal duration, while the duration of individuals treated with J. mimosifolia at 10% was significantly reduced. Occurred reduction in larval survival of individuals treated with aqueous extracts of J. decurrens and J. mimosifolia. Eggs from treatments with aqueous extract of J. decurrens and J. mimosifolia had reduced survival. Pupal survival of individuals treated with extract at 15% showed a significant reduction compared to the treatments at 5% and 10%. Pupae from the treatment with aqueous extract of Jacaranda mimosifolia showed a reduction in biomass in the treatment at 15% differing from the control e 5%. Thus, the aqueous extracts of the species J. decurrens and J. mimosifolia show insecticidal potential in the tests performed on P. xylostella.

Resumo O objetivo deste trabalho foi avaliar o potencial do óleo essencial dos genótipos LGRA-106 e LGRA-108 de Lippia gracilis no controle de traça-das-crucíferas (Plutella xylostella). As concentrações letais (CLs) foram estimadas por duas vias de ação (residual e pulverização), com uso dos óleos em concentrações de 0,5 a 3,0% v v−1, diluídos em Tween 80 (1,5%). Para determinar o efeito da CL média (CL50) no desenvolvimento de P. xylostella, dois compostos dos genótipos de L. gracilis, timol e carvacrol, foram pulverizados nos insetos. A repelência da CL50 foi avaliada por ação residual, em bioensaio com chance de escolha. O genótipo LGRA-106 apresentou maior toxicidade via ação residual (CL50 = 8,82 mg mL−1), bem como maior índice de repelência. Já o LGRA-108 foi mais tóxico via pulverização (CL50 = 9,64 mg mL−1). O desenvolvimento e a viabilidade larval foram reduzidos em cerca de 50% com o LGRA-106 ou o timol e, em até 70%, com o LGRA-108 ou o carvacrol, que causaram mortalidade de 1,70 a 1,97 dias após a pulverização. Os óleos dos genótipos LGRA-106 e LGRA-108 de L. gracilis possuem atividade inseticida no controle de P. xylostella.

Abstract The objective of this work was to evaluate the potential of the essential oils of the LGRA-106 and LGR A-108 Lip pia g racili s genot y pes for the control of diamondback moth (Plutella xylostella). The lethal concentrations (LCs) were estimated by two routes of action (residual and spraying), using oil concentrations ranging from 0.5 to 3.0% v v−1, diluted in Tween 80 (1.5%). To determine the effect of the LC to 50% (LC50) on the development of P. xylostella, two compounds of the L. gracilis genotypes, thymol, and carvacrol, were sprayed on the insects. The repellency of the LC50 was evaluated by residual action, in a free-choice behavioral bioassay. The LGRA-106 genotype showed a greater toxicity via residual action (LC50 = 8.82 mg mL−1), as well as a higher repellency index. LGRA-108 was more toxic via spraying (LC50= 9.64 mg mL−1). Larval development and viability were reduced in approximately 50% with LGRA-106 or thymol and up to 70% with LGRA-108 or carvacrol, which caused mortality from 1.70 to 1.97 days after spraying. The oils of the LGRA-106 and LGRA-108 genotypes of L. gracilis have insecticidal activity in the control of P. xylostella.

Abstract It is essential to understand the effects of sublethal concentrations of insecticides have on the dynamics, biology, and development of pests such as Plutella xylostella, one of the most important pests in the world. This species can develop resistance to the insecticides used for its control. In the present study, abamectin selection pressure was performed for ten generations of P. xylostella, and the sublethal concentrations (CL20) and susceptible lines of the resistance were determined. Then, these concentrations were applied to third instar larvae. In two generations it was evaluated the effect on the percentage of pupae formed, pupal weight, adult emergence, and the development times of each phase from egg to adult. The resistance and application of sublethal concentrations have considerable costs in the biology and development of P. xylostella by increasing the percentage of pupation from one generation to another, and a greater weight of pupae and eggs per female/day. However, it presents a transgenerational effect by reducing oviposition in its generation; in terms of development time, it presented a harmful effect by prolonging it by more than seven days, which would generate a greater number of applications per cycle.

Resumen Es fundamental comprender los efectos que el uso de concentraciones subletales de insecticidas puede tener en la dinámica, biología y el desarrollo de plagas como Plutella xylostella, una de las plagas de mayor importancia a nivel mundial. Esta especie tiene la capacidad de desarrollar resistencia fácilmente a los insecticidas utilizados para su control. En el presente estudio, se realizó una presión de selección de abamectina durante diez generaciones de P. xylostella y se determinaron las concentraciones subletales (CL20) de las líneas resistente y susceptible. Luego, estas concentraciones se aplicaron a larvas de tercer instar y se evaluó el efecto sobre el porcentaje de pupas formadas, peso de pupas, emergencia de adultos, en dos generaciones, así como los tiempos de desarrollo de cada una de las fases desde huevo hasta adulto. La resistencia y la aplicación de concentraciones subletales presenta costos importantes en la biología y desarrollo de P. xylostella al aumentar el porcentaje de pupación de una generación a otra, así como un mayor peso de pupas, un mayor número de huevos por hembra/día. Sin embargo, se presenta un efecto transgeneracional al disminuir la oviposición en sus descendientes; en lo que se refiere al tiempo de desarrollo, presentó un efecto nocivo al prolongarlo en más de siete días lo que generaría un mayor número de aplicaciones por ciclo.

Abstract: Plutella xylostella is a major pest of cruciferous crops in more than 100 countries. The main control method for P. xylostella is based on the use of chemical insecticides. However, this moth species is characterized by its rapid development of resistance to almost all insecticides. The application of low concentrations of insecticides can affect the physiology, biochemistry, and ecology of insects. In this study, a cypermethrin resistance selection was performed during eight generations of P. xylostella and the sublethal dose (LC20) of the resistant line and the susceptible line was determined. Later, the sublethal dose was applied to third instar larvae to investigate its effect on the percentage of pupation, weight of pupae, emergence of adults in two generations (parents and offspring), as well as the development times of each phase of development of P xylostella. A decrease was observed in the percentage of formed pupae, emerged adults and pupal weight. On the other hand, the number of oviposited eggs increased when individuals were exposed to the insecticide. The above can be an important factor for the management and control of this pest when problems of resistance to cypermethrin occur.

Resumen: Plutella xylostella es una importante plaga de cultivos de brassicas en más de 100 países. El principal método de control de P. xylostella se basa en el uso de insecticidas químicos. Sin embargo, esta especie se caracteriza por su rápido desarrollo de resistencia a casi todos los insecticidas. Se ha reportado que la aplicación de concentraciones bajas de insecticidas afecta la fisiología, bioquímica y ecología de los insectos. En este estudio, se realizó una selección de resistencia de cipermetrina durante ocho generaciones de P. xylostella y se determinó la dosis subletal (CL20) de la línea resistente y de la línea susceptible. Posteriormente, la dosis subletal se aplicó a larvas de tercer instar para investigar su efecto en el porcentaje de pupación, peso de pupas, emergencia de adultos en dos generaciones (progenitores y descendientes), así como los tiempos de desarrollo de cada fase de desarrollo de P. xylostella. Se observó una disminución el porcentaje de pupas formadas, adultos emergidos y peso de pupas. Por otro lado, el número de huevos depositados aumentó cuando los individuos fueron expuestos al insecticida. Lo anterior puede ser un factor importante para el manejo y control de esta plaga cuando se presenten problemas de resistencia a cipermetrina.

The diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae), is a cosmopolitan pest that causes leaf-area reduction in Brassicaceae plants. DBM populations have significant genetic variability that manifests in different feeding preferences and reproductive behaviors across generations. We evaluated the influence of Brassicaceae cultivars on biological and behavioral parameters across 18 generations of DBM populations that were separated and held on three varieties of Brassicaceae: Brassica oleracea var. acephala (kale), Brassica oleracea var. italica (broccoli), and Brassica oleracea var. capitata (cabbage). P, F6, F12, and F18 generations were evaluated, and biological aspects of young adulthood and fertility parameters of adults held on each host plant were examined over multiple generations. Additionally, larvae and adults were subjected to dual-choice and multiple-choice (feeding and oviposition) between cultivars, over generations. The results indicated that larvae of P. xylostella consumed greater quantities of kale and broccoli cultivars, on average (4.05 cm2), than cabbage (2.7 cm2). The number of eggs per female in F18 generation was 1.95 and 2.17 times higher than those in the parental (P) generation, when reared on kale and cabbage. The population reared exclusively on kale had higher net population growth rate (R0), intrinsic rate (rm), finite rate (λ) and generation time (T) than that reared on broccoli and cabbage. Last generations evaluated, the larval stage reared on cabbage showed feeding preference (F18) and oviposition preference (F12 and F18) for cabbage. Thus, we note the existence of learning, characterized as pre-imaginal conditioning to cabbage cultivars, over various DBM generations.