Abstract Weevils (Coleoptera: Curculionidae) are one of the main pests in citrus production systems due to their distribution and way of feeding. The objective of this work was to morphologically identify the species of weevils associated with the cultivation of Persian lime (Citrus latifolia Tanaka) in the citrus zone of the municipality of Huimanguillo, Tabasco, Mexico. The captures of weevils were made directly in the canopy, from September 2019 to February 2021, for a total of 17 collected in three Persian lemon plantations, two with conventional management and one with organic management, each one with useful plots of two hectares (624 plants). A total of 1,039 weevils corresponding to four morphospecies were collected, of which 240 were morphologically identified as Epicaerus sp. (1), 355 as Epicaerus sp. (2), 112 as Exophthalmus opulentus and 332 as Cleistolophus subfasciatus.

Resumen Los picudos (Coleoptera: Curculionidae) son una de las principales plagas en los sistemas de producción citrícola debido a su distribución y forma de alimentación. El objetivo del presente trabajo fue identificar morfológicamente las especies de picudos asociados al cultivo de limón persa (Citrus latifolia Tanaka) en la zona citrícola del municipio de Huimanguillo, Tabasco, México. Las capturas de picudos se realizaron de manera directa en la copa de los árboles, de septiembre de 2019 a febrero de 2021, para un total de 17 muestreos en tres plantaciones de limón persa, dos con manejo convencional y una con manejo orgánico, cada una con parcelas útiles de dos hectáreas (624 plantas). Se colectaron 1,039 picudos correspondientes a cuatro morfoespecies, de las cuales 240 se identificaron morfológicamente como Epicaerus sp. (1), 355 como Epicaerus sp. (2), 112 como Exophthalmus opulentus y 332 como Cleistolophus subfasciatus.

Abstract The objective of this work was to evaluate the photosynthetic response of citrus varieties to the inoculation of isolates T30 and T3 of Citrus tristeza virus (CTV) characterized as having potential to provide cross-protection against severe CTV isolates in citrus. Citrus plants of 'Campbell' orange, 'Persian' lime, and 'Key' lime were subjected to inoculations by both isolates by patch. Noninoculated plants were used as the control. Symptom expression, photosynthetic and transpiration rates, and stomatal conductance were evaluated by IRGA. Stomatal density and size were evaluated by epidermal impressions. The CTV isolates were also evaluated and molecularly characterized by RT-PCR and Sanger sequencing. 'Campbell' orange and 'Persian' lime plants remained asymptomatic after the inoculations. The inoculation treatments with both CTV isolates did not reduce photosynthetic capacity, transpiration rate, and stomatal conductance, in comparison with the control. Stomatal density and size varied according to the citrus species. T30 and T3 do not affect the photosynthetic responses of 'Campbell' orange and 'Persian' lime; therefore, these isolates have the potential to provide cross-protection to citrus varieties against severe isolates of CTV.

Resumo O objetivo deste trabalho foi avaliar a resposta fotossintética de variedades de citros submetidas à inoculação dos isolados T30 e T3 de Citrus tristeza virus (CTV) caracterizados como tendo potencial para conferir proteção cruzada a citros contra isolados severos de CTV. Plantas de citros de laranja 'Campbell', limão 'Tahiti' e limão 'Galego' foram submetidas à inoculação de ambos os isolados por “patch”. Plantas não inoculadas foram utilizadas como controle. A expressão dos sintomas, as taxas fotossintética e de transpiração, e a condutância estomática foram avaliadas por IRGA. A densidade e o tamanho estomáticos foram avaliados por impressões epidérmicas. Os isolados de CTV também foram avaliados e caracterizados molecularmente por RT-PCR e sequenciamento de Sanger. As plantas de laranja 'Campbell' e limão 'Tahiti' permaneceram assintomáticas após as inoculações. Os tratamentos de inoculação com ambos os isolados de CTV não reduziram capacidade fotossintética, taxas de transpiração e condutância estomática, em comparação ao controle. A densidade e o tamanho estomáticos variaram de acordo com a espécie. T30 e T3 não afetam as respostas fotossintéticas de laranja 'Campbell' e limão 'Tahiti'; portanto, estes isolados têm potencial para promover proteção cruzada a variedades de citros contra isolados severos de CTV.

Abstract The objective of this work was to estimate the genetic parameters and to evaluate the genotypic diversity of 12 'Tahiti' acid lime (Citrus latifolia) genotypes grafted onto two rootstocks. The experiment was carried out from July 2017 to January 2019, in the municipality of São Mateus, in the state of Espírito Santo, Brazil. Vegetative (stem diameter, canopy projection diameter, and plant height), productive (yield and fruit number), and fruit quality (fruit diameter, soluble solids content, and juice yield) traits were determined. A mixed model was used to estimate heritability and repeatability coefficients, as well as to predict clonal values. Scion diversity was determined through the standardized mean difference of Euclidean distances, and genotypes were clustered by modified Tocher. Clustering quality and trait importance were evaluated using the principal component analysis (PCA). Genotypic variance was observed, which is indicative of the possibility of selection of superior genotypes. The Tocher method showed the presence of three clusters, which is in alignment with the PCA results. The multivariate analyses allows of the selection and the recommendation of superior 'Tahiti' acid lime genotypes.

Resumo O objetivo deste trabalho foi estimar os parâmetros genéticos e avaliar a diversidade genética de 12 genótipos de lima ácida 'Tahiti' (Citrus latifolia) enxertados em dois porta-enxertos. O experimento foi conduzido de julho de 2017 a janeiro de 2019, no município de São Mateus, no estado de Espírito Santo, Brasil. Foram mensuradas características vegetativas (diâmetro de caule, diâmetro de projeção de copa e altura de planta), produtivas (rendimento e número de frutos) e de qualidade de frutos (diâmetros de fruto, teor de sólidos solúveis e rendimento de suco). Utilizou-se modelo misto para estimar os coeficientes de herdabilidade e repetibilidade, bem como predizer os valores genéticos. A diversidade entre os enxertos foi obtida por meio da diferença da distância euclidiana média padronizada, e os genótipos foram agrupados pelo método de Tocher modificado. A qualidade do agrupamento e a importância dos caracteres foi avaliada pela análise de componentes principais (ACP). Observou-se variabilidade genética, o que indica a possibilidade de seleção de genótipos superiores. O método de Tocher mostrou a presença de três grupos de genótipos, o que foi congruente com os resultados da ACP. O uso de técnicas multivariadas permite a seleção e a recomendação de genótipos superiores de lima ácida 'Tahiti'.

ABSTRACT It is necessary to diversify the scion/rootstock combinations for Persian lime cultivation, notably under tropical rainfed conditions. Therefore, in this work we evaluated the performance of a new cultivar, BRS EECB IAC Ponta Firme, up to six years after planting on 26 citrus rootstocks under Aw climate in northern São Paulo state, Brazil. Thirty single-tree randomized replications of each rootstock were evaluated without irrigation at 1,000 trees·ha-1. Lemon-type, followed by mandarin rootstocks induced the largest tree size and higher mean yield, probably related to the higher drought tolerance. The true dwarfing rootstocks of Flying Dragon trifoliate orange and Lindcove citrandarin were highly drought-intolerant, but, in addition to Swingle citrumelo and four other citrandarins, they did not present huanglongbing-symptomatic trees during the evaluation period under strict control of the insect vector. Overall, BRS EECB IAC Ponta Firme fruit quality was minimally influenced by the rootstock cultivar and fulfilled the requirements for both domestic and export fresh fruit markets. Due to superior production efficiency associated with high yield in relation to the canopy size, the Goutoucheng sour orange, BRS Ary, BRS Bravo and BRS Matta hybrids were selected as potential rootstocks of rainfed BRS EECB IAC Ponta Firme lime under Aw climate (tropical savannah) conditions.

Resumen La enfermedad de los cítricos conocida como Huanglongbing (HLB) es una de las más importantes a nivel mundial. Desde 2009 hasta la actualidad, México realiza el monitoreo poblacional y control del insecto vector de esta enfermedad, el psílido asiático Diaphorina citri, mediante el uso de insecticidas y enemigos naturales. El objetivo de esta investigación fue estimar la distribución espacio-temporal de las poblaciones de D. citri en lima persa Citrus latifolia bajo un esquema de manejo regional en Nayarit, México. El estudio se llevó a cabo de agosto de 2018 a Julio de 2020 en dos ambientes: cálido subhúmedo y en semicálido subhúmedo. Se estimó la fluctuación temporal y distribución espacial mediante la captura de adultos del psílido en huertos de las dos zonas climáticas. Se utilizaron 2.041 trampas amarillas distribuidas en 1.100 hectáreas, las cuales se revisaron quincenalmente. Se realizaron análisis de varianza del número de adultos entre localidades, por zona climática y entre meses del año. Se estimaron correlaciones entre la población y la temperatura y la precipitación pluvial. La población de adultos de D. citri fue estadísticamente similar entre huertos de una misma zona climática, por lo que se justifica un manejo similar por zona climática. En ambos climas se detectó diferencia significativa de poblaciones de D. citri entre los meses del año. En clima cálido subhúmedo, las poblaciones más altas de adultos de D. citri se registraron en julio-agosto y en clima semicálido subhúmedo, ocurrieron en febrero-marzo y agosto por lo que se requeriría aplicar una medida de control en estos periodos. En este estudio no se detectó correlación significativa entre poblaciones de D. citri con la temperatura ni con la precipitación pluvial. El control de D. citri puede ser regional, diferenciado en cada zona climática y de acuerdo con los meses del año con mayor población.

Abstract The citrus disease known as Huanglongbing (HLB) is one of the most important worldwide. Present in Mexico since 2009, its current management is carried out mainly through population monitoring and control of its insect vector, Diaphorina citri with the use of insecticides and natural enemies. The objective of this research was to estimate the spatio-temporal distribution of Diaphorina citri populations in Persian lime Citrus latifolia with a regional management scheme in Nayarit, Mexico. The study was conducted in 2018-2020 in two environments: warm subhumid and semi-warm subhumid. Temporal fluctuation and spatial distribution were obtained by capturing psyllid adults in orchards in both climatic zones with 2.041 yellow traps, which were reviewed biweekly. Analysis of variance of the number of adults was carried out between localities, by climatic zone and between months of the year. Correlations between populations and temperature and rainfall were estimated. The adult population of D. citri was statistically similar between orchards in the same climatic zone, for which the same management by climatic zone is justified. In both climates, a significant difference in populations of D. citri was detected between the months of the year. In warm subhumid climate, the highest adult populations of D. citri were recorded in July and August, so it would be necessary to apply a control measure in this period. In semi-warm subhumid climates, the highest adult populations of the psyllid occurred in February-March and August, in this period is recommended to apply a control measure. In this study, no significant correlation was detected between populations of D. citri with temperature or rainfall. Control of D. citri can be regional, differentiated in each climatic zone and according to the months of the year with the largest population.

RESUMO: Embora a produtividade seja uma característica fundamental em programas de melhoramento da lima ácida Tahiti, outras características se destacam por proporcionar uma seleção mais eficiente ou mesmo influenciar na expressão de atributos produtivos. A aplicação de inferência Bayesiana, pode tornar o processo de identificação de indivíduos superiores e o estudo das correlações entre as características ainda mais acurado. Objetivou-se, por meio deste estudo, estimar valores genéticos em genótipos de lima ácida Tahiti através de inferência Bayesiana e estimar coeficientes de correlação e de trilha entre características vegetativas, produtivas e de qualidade de frutos. Vinte e quatro genótipos de lima ácida foram avaliados durante dois anos para peso e número de frutos, volume de copa, diâmetro de caule, teor de sólidos solúveis dos frutos, espessura de casca e rendimento de suco. Os valores genéticos foram estimados por meio de inferência Bayesiana e modelos com diferentes estruturas residuais foram testados via critério de informação de deviance. Coeficiente de correlação de Pearson e de análise de trilha foram determinados, removendo o efeito de multicolinearidade. A estimação de valores genéticos via inferência Bayesiana apresentou alta acurácia seletiva. As correlações obtidas entre caracteres de diferentes grupos podem ser úteis em estratégias de seleção para melhoramento da lima ácida Tahiti. A inferência Bayesiana demonstrou ser uma ferramenta importante e deve ser considerada em programas de melhoramento de culturas perenes.

ABSTRACT: Although the fruit yield has a core importance in Tahiti acid lime breeding programs, other traits stand out among the quality fruit and vegetative traits as ones that still need to be improved in selection of superior genotypes. Appling efficient tools aiming selection, such as the Bayesian inference, becomes an alternative in perennial crops. This study applied Bayesian inference in the genetic evaluation of Tahiti acid lime genotypes and estimated the interrelation between vegetative, productive and fruit quality traits. Twenty-four acid lime genotypes were evaluated for number of fruits, fruit yield, canopy volume, stem diameter, soluble solids content, shell thickness, and juice yield traits. The genotypic values were estimated through Bayesian inference and models with different residual structure were tested via deviance information criterion. Pearson’s correlation and the path analysis were estimated, removing the multicollinearity effect. The Bayesian inference estimates genotypic values with high selective accuracy. The correlations obtained between traits from different groups can be useful in selection strategies for improvement of Tahiti acid lime. The Bayesian inference demonstrated to be an important tool and should be considered in perennial breeding programs.

Resumo Poucas variedades de porta-enxertos são utilizadas para a limeira-ácida ‘Tahiti’, sendo que a diversificação se faz necessária, e o estudo das fases fenológicas de novas combinações copa/portaenxerto é importante para as estratégias de manejo do pomar. Objetivou-se avaliar a influência de diferentes porta-enxertos no somatório dos graus-dia (GD) e na fenologia das plantas, além da qualidade dos frutos de limeira-ácida ‘Tahiti IAC-5’, em Pindorama-SP. Foram marcados seis ramos em plantas enxertadas em 13 citrandarins (H), no limoeiro ‘Cravo’ (LC), no trifoliata ‘Flying Dragon’ (FD) e na tangerineira ‘Sunki’ (TS). A caracterização fenológica (antese à colheita) foi realizada utilizando-se de uma escala de notas. O acúmulo de GD (antese à colheita) foi determinado considerando-se a temperatura-base de 13 °C. Também foram avaliadas as características físicas (massa, altura, diâmetro e rendimento de suco) e químicas (acidez, sólidos solúveis totais e ratio) dos frutos. O delineamento experimental foi em blocos casualizados, com três repetições e uma planta por parcela. Os porta-enxertos estudados influenciaram no acúmulo de GD e na fenologia, identificando-se combinações precoces (H5, H73, H121, H135, H145, H152, FD - 1.558 a 1.676 GD e 135 a 146 dias) e mais tardias (H10, H14, H42, H47, H70, H150, H173, LC e TS - 1.694 a 1.829 GD e 148 a 157 dias) quanto à maturação de frutos. O ponto de colheita dos frutos de limeira-ácida ‘Tahiti’ enxertada no citrandarim H145 e no FD foi adiantado em torno de 20 dias em relação ao porta-enxerto padrão de LC. Os teores de sólidos solúveis totais e o tamanho dos frutos foram influenciados pelos porta-enxertos, entretanto, todas as combinações apresentaram frutos com características de qualidade dentro dos padrões comerciais.

Abstract Few rootstock varieties are used for ‘Tahiti’ acid lime; therefore, diversification is necessary and studying the phenological phases of new scion/rootstock combinations is important for orchard management strategies. The aim of this study was to evaluate the influence of different rootstocks on the sum of degree days (DD) and on the phenology of plants and also on the quality of ‘Tahiti’ acid lime fruits, in Pindorama, SP. Six branches were marked on plants grafted onto 13 citrandarins (H), ‘Rangpur’ lime (RL), ‘Flying Dragon’ trifoliate orange (FD) and ‘Sunki’ mandarin (SM). Phenological characterization (anthesis to harvest) was performed using a grading scale. DD accumulation (anthesis to harvest) was determined considering the base temperature of 13 °C. Physical (weight, height and diameter, juice yield) and chemical (acidity, total soluble solids and ratio) characteristics of fruits were also evaluated. The experimental design was in randomized blocks with three replicates and one plant per plot. The rootstocks under study influenced DD accumulation and phenology, with early (H5, H73, H121, H135, H145, H152, FD - 1,558 at 1,676 DD and 135 to 146 days) and later combinations (H10, H14, H42, H47, H70, H150, H173, RL and SM - 1,694 to 1,829 DD and 148 to 157 days) regarding fruit maturation. The harvest point of ‘Tahiti’ acid lime fruits grafted onto H145 citrandarin and FD was advanced about 20 days in relation to the standard rootstock, RL. Total soluble solids content and fruit size were influenced by rootstocks; however, all scion/rootstock combinations presented fruits with quality characteristics within commercial standards.

ABSTRACT The red palm mite Raoiella indica Hirst has recently invaded the Neotropical region, which demands the implementation of pest management strategies. In this study, toxicity of leaf extracts of Mexican oregano Lippia berlandieri Schauer, neem Azadirachta indica A. Juss, Mexican mint Plectranthus amboinicus (Lour.) Spreng., rue Ruta graveolens L. and Persian lime Citrus x latifolia Tanaka against R. indica was evaluated under laboratory conditions. Raoiella indica females were exposed to each plant extract at concentrations of 0.25, 0.50, 0.75 and 1% (v/v) to assess the cumulative mortality at 24, 48 and 72 h after exposure. Mortality rates of R. indica rose due to increased extract concentration and exposure time. The strongest acaricidal activity was observed with L. berlandieri, A. indica and P amboinicus, whose 1% concentration and 72 h exposure caused a mean R. indica mortality of 100, 90 and 78%, respectively. These plant extracts hold promise for the chemical management of this pest.

RESUMEN El ácaro rojo de las palmas Raoiella indica Hirst es una plaga de reciente invasión en la región Neotropical, que demanda la implementación de estrategias de manejo. En este estudio se evaluó la toxicidad de los extractos de hojas de orégano mexicano Lippia berlandieri Schauer, neem Azadirachta indica A. Juss, menta mexicana Plectranthus amboinicus (Lour.) Spreng., ruda Ruta graveolens L. y limón persa Citrus x latifolia Tanaka contra R. indica en condiciones de laboratorio. Las hembras de R. indica se expusieron a cada extracto vegetal en concentraciones de 0.25, 0.50, 0.75 y 1% (v/v) para evaluar la mortalidad acumulada a las 24, 48 y 72 h después de la exposición. Los porcentajes de mortalidad de R. indica se incrementaron debido al aumento de la concentración del extracto y tiempo de exposición. La actividad acaricida más importante se observó con L. berlandieri, A. indica y P amboinicus, cuya concentración de 1% y 72 h de exposición causó una mortalidad promedio de 100, 90 y 78% de ácaros, respectivamente. Estos extractos vegetales son promisorios para el manejo químico de esta plaga.

ABSTRACT Combining longitudinal data and statistical models from perennial crops enabled us to estimate the optimum number of measures (harvests), implying accurate discrimination of superior genotypes in those crops. Herein, the goal of this study was to determine the optimum number of harvests based on yield traits and recommend a superior graft/rootstock combination (GRC) for Citrus latifolia Tanaka. Twenty-four GRCs of 'Tahiti' acid lime were evaluated from July 2017 to August 2018 for fruit yield per plant (FYP), number of fruits per plant (NFP), and longitudinal (LFD) and transversal fruit diameter (TFD). The experimental design was a randomized complete block with 4 replications. The experimental unit consisted of three individuals, totalling 244 individuals. The GRCs were composed of (i) two hybrids that were used as rootstock, citrumelo ‘Swingle’ (Citrus paradisi x Poncirus trifoliata) and cintrandarin ‘Riverside’ (Citrus sunki x Poncirus trifoliata); and (ii) 12 different C. latifolia genotypes that were used as grafts: Bello Fruit, Eledio, Iconha, Itarana, Santa Rosa, Bearss lime, CNPMF 01, CNPMF 02, CNPMF 2001, CNPMF 5059, BRS Passos, and Persian 58. Mixed models were employed to estimate the variance components. The optimum number of harvests was determined based on selective efficiency values above 0.9. The estimated repeatability coefficients presented values of 0.14 (LFD), 0.16 (TFD), 0.36 (FYP), and 0.38 (NFD). Based on the results, four harvests were able to choose genotypes based on FYP and NFP, whereas LFD and TFD were considered inefficient traits for recommending superior GRCs.

RESUMO A interferência de ervas daninhas em pomares cítricos jovens causa danos significativos, especialmente quando a competição ocorre durante a estação seca, quando os recursos ambientais são ainda mais escassos. Objetivou-se testar os efeitos de períodos de interferência e do manejo de plantas daninhas na fisiologia, produtividade e qualidade de frutos de limão persa, durante a estação seca. O delineamento experimental foi em blocos casualizados, com cinco tratamentos [capina com enxada; aplicação de glifosato; diminuição da água armazenada (março a maio); déficit hídrico crítico (junho a agosto); e déficit hídrico ao longo da estação seca (março a agosto)] e quatro repetições. A interferência de plantas daninhas durante o período de diminuição da água armazenada e déficit hídrico crítico afetou significativamente as variáveis fisiológicas, produtividade e teor de sólidos totais dos frutos, mas em menor grau do que o déficit hídrico ao longo da estação seca. O controle com glifosato resultou em 1,56 e 2,53 vezes mais frutos por árvore do que a capina e o déficit hídrico ao longo da estação seca, respectivamente. O manejo químico proporcionou melhores respostas fisiológicas e produtivas do que a capina, devido ao efeito da cobertura morta de plantas daninhas na estação de déficit hídrico.

ABSTRACT Weed interference in young citrus orchards causes significant damages, especially when competition occurs during the dry season, when environmental resources are even more scarce. This study aimed to test the effects of interference periods and weed management on the physiology, yield and quality of Persian lime fruits, during the dry season. The experimental design was randomized blocks, with five treatments [hoeing; glyphosate application; decrease of stored water (March to May); critical water deficit (June to August); and water deficit throughout the dry season (March to August)] and four replications. Weed interference during the decrease of stored water and critical water deficit periods affected significantly the physiological variables, yield and total solids contents of the fruits, but to a lesser extent than for the water deficit throughout the dry season. Weed control with glyphosate resulted in 1.56 and 2.53 times more fruits per tree than hoeing and water deficit throughout the dry season, respectively. The chemical management provided better physiological and productive responses than hoeing, due to the effect of weed mulch in the water deficit season.

Abstract A good bioindicator of soil health is one that perceives minor changes due to changes in soil management and leads to changes in the processes of the soil ecosystem. The aim was to evaluate the use of soil bioindicators in the determination of the utility of two different Cedrela odorata forestry management systems. The litter and soil samples were collected from the rhizosphere of a monoculture (with no fertilization nor irrigation), and a co-culture (with fertilization and irrigation) stand with Citrus latifolia. The soil and litter bioindicators measured were the activity of acetylesterase (FDA), acid phosphatase (AcPh), alkaline phosphatase (AlkPh), laccase, and the estimation of the potential net rate of carbon mineralization (PNRCM). The results indicated that soil enzyme activities (FDA and phosphatases) in the litter were sensitive to the different management system treatments. Enzymatic activity, per unit dry weight, was higher in litter of co-culture (FDA = 1.05 nkat g-1 AcPh = 1.33 nkat g-1; AlkPh = 03.0 nkat g-1) than in litter of monoculture (FDA = 0.617nkat g-1; AcPh = 0.40 nkat g-1; AlkPh = 0. 983 nkat g-1). Differences in soil total nitrogen content, organic matter (OM) content, and micronutrients were found. In general, the co-culture stand (with fertilization and irrigation) with C. latifolia showed the best results.

Resumen Un buen bioindicador de la salud del suelo es aquel que percibe cambios menores, debidos a modificaciones en el manejo del suelo, y conduce a cambios en los procesos del ecosistema suelo. El objetivo fue evaluar el uso de bioindicadores de suelo en la determinación de la utilidad de dos sistemas diferentes de manejo forestal de Cedrela odorata . El mantillo y el suelo se recolectaron de la rizosfera de un monocultivo (sin fertilización ni irrigación) y un cocultivo (con fertilización e irrigación) con Citrus latifolia. Los bioindicadores de suelo y mantillo medidos fueron: las actividades acetilesterasa (FDA), fosfatasa ácida (AcPh), fosfatasa alcalina (AlkPh) y lacasa. También se estimó la tasa neta potencial de mineralización de carbono (PNRCM). Los resultados indican que las actividades enzimáticas del suelo (FDA y fosfatasas) en el mantillo fueron sensibles a los diferentes sistemas de manejo. La actividad enzimática, por unidad de peso seco, fue mayor en los cocultivos (FDA = 1.05 nkat g-1; AcPh = 1.33 nkat g-1; AlkPh = 3 nkat g-1) que en los monocultivos (FDA = 0.617 nkat g-1; AcPh = 0.40 nkat g-1; AlkPh = 0. 983 nkat g-1). Se encontraron diferencias en la cantidad de nitrógeno total, el contenido de materia orgánica (MO) y los micronutrientes. En general, los cultivos (con fertilización e irrigación) con C. latifolia mostraron los mejores resultados.

Resumo O Brasil representa em grande percentual a produção mundial de citros, destacando dentre várias espécies cultivadas, a limeira ácida ‘Tahiti’. No entanto, seu cultivo é sustentado por uma base genética muito estreita, sendo composto por poucas opções de copa e porta-enxerto. Deste modo, objetivou-se avaliar o desenvolvimento vegetativo e a produção de doze clones de limeira ácida ‘Tahiti’ sobre dois porta-enxertos. O experimento foi conduzido na Fazenda José Guarete, no município de São Mateus – ES. Utilizou-se o delineamento experimental de blocos ao acaso, no esquema de parcelas subdivididas, com a parcela sendo constituída por dois porta-enxertos e a subparcela, os doze clones de limeira ácida ‘Tahiti’. Foram avaliadas as características: desenvolvimento vegetativo, produção e eficiência produtiva, qualidade interna e externa dos frutos. Os clones Bello Fruit, Iconha, BRS Passos, Itarana, Persian 58, CNPMF 5059 e Elédio foram superiores nas características produtivas, vegetativas e na qualidade do fruto. O porta-enxerto citrumelo ‘Swingle’ apresentou valores referentes a características vegetativas superiores ao citrandarin ‘Riverside’. As combinações de clone e porta-enxerto que proporcionaram melhor desempenho agronômico neste estudo foram BRS Passos, Bello Fruit, Elédio e Iconha enxertadas no citrumelo ‘Swingle’ e CNPMF 5059, Iconha e Elédio sobre o citrandarin ‘Riverside’.

Abstract Brazil accounts for a large percentage of the world’s citrus production, with ‘Tahiti’ acid lime tree standing out among several cultivated species. However, its cultivation is supported by a very narrow genetic base, being composed of few scion and rootstock options. In this way, the aim of this study was to evaluate the vegetative development and production of twelve ‘Tahiti’ acid lime clones on two rootstocks. The experiment was carried out at Fazenda José Guarete, municipality of São Mateus – ES. A randomized block design was used in the split plot scheme, with plot consisting of two rootstocks and subplot of the twelve ‘Tahiti’ acid lime clones. Traits evaluated were: vegetative development, production and productive efficiency, internal and external quality of fruits. Bello Fruit, Iconha, BRS Passos, Itarana, Persian 58, CNPMF 5059 and Elédio clones were superior in terms of production, vegetative traits and fruit quality. ‘Swingle’ citrumelo rootstock showed higher values for vegetative traits compared to ‘Riverside’ citrandarin. The clone and rootstock combinations that provided better agronomic performance in this study were BRS Passos, Bello Fruit, Elédio and Iconha grafted on ‘Swingle’ citrumelo and CNPMF 5059, Iconha and Elédio grafted on ‘Riverside’ citrandarin.

Abstract Aleurocanthus woglumi (Ashby, 1915) is an important agricultural pest that causes yield losses of 20-80% in citrus plants by removing plant nutrients while feeding and allowing the formation of sooty mold. The objective of this study was to evaluate physiological changes in citrus plants in response to A. woglumi infestation under field conditions. The experiment was conducted in a citrus orchard in Paço do Lumiar, Maranhão, Brazil. Thirty-two citrus plants were used, including eight of each of the following varieties: Tahiti lime, Tanjaroa tangerine, Nissey tangerine, and Ponkan tangerine. Four random plants with A. woglumi infestation and four plants free from this pest were selected from each variety. The physiological parameters evaluated were photochemical efficiency and gas exchange. Regarding photochemical efficiency, infested plants presented photoinhibition damage, with a performance index of 4.22. The gas exchange parameters of infested plants changed, with reductions in photosynthetic CO2 assimilation of 69.7% (Tahiti), 64% (Tanjaroa), 68.8% (Nissey) and 63.3% (Ponkan). Plants infested with A. woglumi also presented physiological changes; their photosynthetic CO2 assimilation, stomatal conductance, instantaneous transpiration, and performance indexes were affected. The infested citrus plants showed photoinhibition of photosystem II. The photosynthetic CO2 assimilation decreased approximately 70% in Tahiti lime, Tanjaroa tangerine, Nissey tangerine, and Ponkan tangerine plants infested with A. woglumi.

Abstract. The distribution, incidence and severity damage caused by the dieback complex (Lasiodiplodia spp.) in Persian lime (Citrus latifolia) was determined in 46 orchards of six average years old, 25 trees per orchard in the municipalities of Amacuzac, Ayala, Coatlan del Rio, Cuautla, Jantetelco, Jonacatepec, Puente de Ixtla, Tepalcingo and Tlaltizapan of Zapata, Morelos State, Mexico. Incidence was evaluated according to the number of plants having symptoms of dieback. There were four levels of severity, where 0= healthy tree, 1= gum exudation, 2= cracking with exposure of internal tissue and 3= well-defined canker and branch dieback. Which were transformed to a percentage of means of a scale of three levels of severity, transforming to a percentage of infection using the Townsend and Heuberger equation. Data were analyzed trough the Kruskal Wallis test and Tukey (α=0.05) and p<0.0001 in incidence and severity. There was a high incidence of dieback on stems 78% of Persian lime trees. The incidence and severity of dieback of Persian trees on different orchards had a range of 31.8 to 100% and 30 to 100%, respectively. By the other hand, municipalities such as Amacuzac, Ayala, Coatlan del Rio and Tlaltizapan, had the lowest levels of incidence and severity of dieback.

Resumen. Se determinó la distribución, incidencia y severidad de la muerte descendente (Lasiodiplodia spp.) en lima persa (Citrus latifolia) en 46 huertos de seis años de edad, 25 árboles por huerto en los municipios de Amacuzac (7 huertos), Ayala (4), Coatlán del Río (9), Cuautla (1), Jantetelco (5), Jonacatepec (1), Puente de Ixtla (5), Tepalcingo (3) y Tlaltizapán de Zapata (11), del estado de Morelos, México. La incidencia fue determinada con base al número de plantas enfermas y la severidad mediante escala de daño de cuatro clases: 0= árbol sano, 1= exudación de goma, 2= agrietamiento con exposición de tejidos internos y 3= cancro bien definido y muerte descendente de ramas. La severidad fue transformada a porcentaje de infección con la fórmula de Townsend y Heuberger, analizados por Kruskal Wallis y separados por la comparación de medias, prueba de Tukey (α= 0.05) y p< 0.0001 en incidencia y severidad. La enfermedad se registró en el 78% de los huertos, con incidencias de 31.8 a 100% y severidades de 30.0 al 100%. Los huertos con menor incidencia y severidad fueron los ubicados en Amacuzac, Ayala, Coatlán del Río y Tlaltizapán de Zapata.

Abstract This work had the purpose of detecting the presence of phytoplasmas associated to HLB-like symptoms, a disease caused by CLas, to improve the sampling and detection carryout in official phytosanitary actions in the Mexican citriculture. Base on alerts of negative results to CLas in citrus trees with putative symptoms of HLB, directed samplings were conducted in commercial orchards and country backyards in Hidalgo, Colima, Puebla and Veracruz in 2012, 2013 and 2018. The total DNA was analyzed by PCR with the primers P1 / P7 nested with R16F2 / R16R2 and D7f2 / D7r2. CLas infection was assessed with A2 / J5 primers. The presence of the Brazilian Huanglongbing disease-associated phytoplasma, member of the 16Sr IX group, associated with C. latifolia (NCBI, MK282760) and C. aurantifolia (NCBI, MK282761) was confirmed inducing similar but contrasting symptoms to those caused by CLas. These hosts are reported for the first time in addition to the original report on C. sinensis in Brazil. Bidens odorata and Cajanus cajan are also reported as probable alternate weed hosts as well as the presence of specimens of Graphocephala and Acinopterus (Cicadellidae), genera recognized with vector species of 16Sr III-A and Aster Yellow phytoplasma groups, respectively.

Resumen Este trabajo tuvo la finalidad de investigar la presencia de fitoplasmas asociados a síntomas similares al HLB, enfermedad causada por CLas, con el propósito de optimizar los procesos de muestreo y diagnóstico en el marco de acciones fitosanitarias oficiales en la citricultura Mexicana. A partir de alertas de resultados negativos a CLas en árboles de Citrus spp con síntomas putativos de HLB se realizaron muestreos dirigidos en huertos comerciales y traspatios en Hidalgo, Colima, Puebla y Veracruz en 2012, 2013 y 2018. El ADN total se analizó por PCR con los iniciadores P1/P7 anidados con R16F2/R16R2 y D7f2/D7r2. La infección de CLas se determinó con los iniciadores A2/J5. Se confirmó en México la presencia del Brazilian Huanglongbing disease-associated phytoplasma, miembro del grupo 16Sr IX, asociado a C. latifolia (NCBI, MK282760) y C. aurantifolia (NCBI, MK282761) induciendo síntomas similares pero contrastantes a los causados por CLas. Estos hospederos se reportan por primera vez en adición al original reporte en C. sinensis en Brasil. También se reporta a Bidens odorata y Cajanus cajan como probables hospederos arvenses alternos y la presencia de especímenes de Graphocephala y Acinopterus (Cicadellidae), géneros reconocidos con especies vectoras de fitoplasmas de los grupos 16Sr III-A y Aster Yellow, respectivamente.