Abstract Glyphosate is a broad-spectrum herbicide that has been applied to agricultural fields in more than 200 countries for 40 years. Due to recent studies that demonstrated its relationship as a carcinogen, a worldwide debate has opened about its use and prohibition. Mexico has joined the movement to ban its use in the decree issued in December 2020. Due to its constant application, residual glyphosate impacts different environmental compartments, including the soil. Therefore, the objective was to identify the agricultural practices and weed management used in the ejido of Bella Esperanza, Coatepec, Veracruz, as part of the characterization of the sampling site for the research project on the bioremediation of glyphosate with endogenous microorganisms. Through a field approach, surveys were carried out with producers in the area, where the results showed that 54% use glyphosate as their primary weed control. They do not use any protective equipment either and consider glyphosate a product harmless to the environment. In the same way, the result of this study observed that the ejido of Bella Esperanza is a suitable sampling area for studying microorganisms with possible applications in bioremediation.

Resumen El glifosato es un herbicida de amplio espectro que ha sido aplicado en los campos agrícolas de más de 200 países desde hace 40 años. Debido a recientes investigaciones que demostraron su relación como cancerígeno, se ha abierto un debate a nivel mundial sobre su uso y prohibición. México se ha sumado al movimiento de prohibir su uso en el decreto emitido en diciembre de 2020. El efecto del glifosato residual debido a la aplicación constante del mismo tiene afectaciones en diferentes compartimentos ambientales, entre ellos el suelo. Por lo tanto, el objetivo fue identificar las prácticas agrícolas y manejo de arvenses que se emplean en el ejido de Bella Esperanza, Coatepec, Veracruz, como parte de la caracterización del sitio de muestreo para el proyecto de investigación en torno a la biorremediación del glifosato con microorganismos endógenos. Mediante un acercamiento de campo, se realizaron encuestas a los productores de la zona, donde los resultados mostraron que el 54% emplea el glifosato como principal control de malezas. Asimismo, no emplean ningún equipo de protección y consideran al glifosato como un producto inocuo para el medio ambiente. Del mismo modo, el resultado de este estudio observó que el ejido de Bella Esperanza es un área de muestreo adecuada para el estudio de microorganismos con posibles aplicaciones en biorremediación.

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.

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.

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.

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 Introduction: Rootstock diversification arises as a consequence of the appearance of diseases and the need to improve the yields and productive efficiency of orchards. Objective: To establish the relationship between the anatomical characteristics of the stem of four citrus rootstocks and the initial growth of 'Tahiti' lime (Citrus x latifolia Tanaka ex Q. Jiménez). Materials and methods: The rootstocks ‘Volkamer’ lemon (C. volkameriana Tenn. & Pasq.), sour orange (Citrus aurantium L.), ‘Flying Dragon’ trifoliate orange (Poncirus trifoliata var. monstrosa [T. Ito] Swingle) and ‘Rubidoux’ trifoliate orange (P. trifoliata [L.] Raf.) were evaluated. The degree of correlation between seven characteristics of the initial growth of the graft and eight characteristics of the secondary xylem of the stem of the rootstocks was established. Results and discussion: Sour orange and ‘Volkamer’ lemon showed more vigorous growth; the variables evaluated were 23 to 70 % higher than with 'Rubidoux' and 'Flying Dragon'. The sour and 'Volkamer' rootstocks had xylem vessels of greater area and lower density, as well as greater fiber length and xylem radiuses; these characteristics were correlated with higher shoot length and diameter values, growth rate, number of leaves and leaf area of the graft shoot. Smaller vessel size but higher density caused the opposite effect on graft growth. Conclusion: Vessel density, diameter and length, and fiber length showed higher correlations with the growth variables, so they can be used as prediction characteristics for graft growth.

Resumen Introducción: La diversificación de portainjertos surge como consecuencia de la aparición de enfermedades y la necesidad de mejorar los rendimientos y la eficiencia productiva de las huertas. Objetivo: Establecer la relación que existe entre las características anatómicas del tallo de cuatro portainjertos de cítricos y el crecimiento inicial del injerto de lima persa ‘Tahiti’ (Citrus x latifolia Tanaka ex Q. Jiménez). Materiales y métodos: Se evaluaron los portainjertos limón ‘Volkameriano’ (C. volkameriana Tenn. & Pasq.), naranjo agrio (Citrus aurantium L.), naranjo trifoliado ‘Flying Dragon’ (Poncirus trifoliata var. monstrosa [T. Ito] Swingle) y naranjo trifoliado ‘Rubidoux’ (P. trifoliata [L.] Raf.). Se estableció el grado de correlación entre siete características del crecimiento inicial del injerto y ocho características del xilema secundario del tallo de los portainjertos. Resultados y discusión: El naranjo agrio y el limón ‘Volkameriano’ mostraron crecimiento más vigoroso; las variables evaluadas fueron 23 a 70 % mayores que con ‘Rubidoux’ y ‘Flying Dragon’. Los portainjertos agrio y ‘Volkameriano’ presentaron vasos del xilema de mayor área y en menor densidad, así como longitud de fibras y radios del xilema mayores; estas características se correlacionaron con valores mayores de longitud y diámetro de brote, velocidad de crecimiento, número de hojas y área foliar del brote del injerto. Un tamaño menor de los vasos, pero mayor densidad, ocasionaron el efecto contrario en el crecimiento del injerto. Conclusión: La densidad, diámetro y longitud de los vasos, y la longitud de las fibras mostraron correlaciones más altas con las variables del crecimiento, por lo que pueden usarse como características de predicción en el crecimiento de injertos.

Early blight is one of the main phytosanitary problems affecting the cultivation of tomato (Solanum lycopersicum L.) and potato (Solanum tuberosum L.). This disease is caused by Alternaria solani, whose control is basically by using synthetic fungicides. In this sense, plants are an alternative in the search for new sources of less aggressive antifungal compounds to the environment. Leaf extracts of Citrus latifolia in ethanol 70 % and Citrus aurantiifolia in methanol 70 % have proven antifungal activity against A. solani. The aim of this study was to determine the effect of these extracts on the cellular membrane and respiration of A. solani. The extracts were obtained by ultrasound-assisted extraction, and the total phenolic content was measured. The effect of the extracts on the cellular membrane and respiration was evaluated by determining the concentrations of phosphorus and potassium in the extracellular medium and the activity of the succinate dehydrogenase enzyme. The high concentrations of phosphorus and potassium found in the extracellular medium suggest damages in the permeability of the cellular membrane of A. solani. Similarly, the inactivity of the succinate dehydrogenase enzyme pointed to an inhibition of the cellular respiration of A. solani by the evaluated citrus extracts. The results obtained in this study confirmed the antifungal properties of leaf extracts of C. latifolia and C. aurantiifolia and suggested its possible use in the agro-ecological management of the causal agent of the early blight disease of tomato and potato

El tizón temprano constituye uno de los principales problemas fitosanitarios que afectan el cultivo del tomate (Solanum lycopersicum L.) y la papa (Solanum tuberosum L.). Esta enfermedad es provocada por Alternaria solani Sor., cuyo control es, básicamente, mediante el uso de fungicidas sintéticos. En este sentido, las plantas constituyen una alternativa en la búsqueda de nuevas fuentes de compuestos antifúngicos menos agresivos para el ambiente. Los extractos de hojas de Citrus latifolia en etanol 70 % y Citrus aurantiifolia en metanol 70 % han mostrado actividad antifúngica frente a A. solani. El objetivo de este trabajo fue determinar el efecto de estos extractos sobre la membrana y la respiración celular de A. solani. Los extractos se obtuvieron mediante extracción asistida por ultrasonido y se cuantificó el contenido de fenoles totales. El efecto de los extractos sobre la membrana y la respiración celular se evaluó mediante la determinación de las concentraciones de fósforo y potasio en el medio extracelular y la actividad de la enzima succinato deshidrogenasa, respectivamente. Las elevadas concentraciones de fósforo y potasio encontradas en el medio extracelular sugieren daños en la permeabilidad de la membrana celular de A. solani. De igual forma, la inactividad de la enzima succinato deshidrogenasa indicó inhibición de la respiración celular por parte de los extractos de cítricos evaluados. Los resultados alcanzados confirman las propiedades antifúngicas de extractos de hojas de C. latifolia y C. aurantiifolia y sugieren su posible uso en el manejo agroecológico del agente causal del tizón temprano del tomate y de la papa

RESUMO Objetivou-se avaliar as características externas e as do suco de lima-ácida ‘Tahiti’, produzida sob adubação nitrogenada e potássica. Utilizou-se o delineamento inteiramente casualizado, com três repetições de quatro frutos das duas plantas centrais, em esquema fatorial 4 x 5, sendo quatro doses de N (0; 25; 50 e 100 Kg. ha-1. ano-1) e cinco doses de K2O (0; 25; 50; 100 e 200 kg. ha-1. ano-1), totalizando 20 tratamentos. Em pós-colheita, avaliaram-se as características externas (tamanho, cor e espessura da casca, firmeza e massa fresca) e as do suco (volume, percentagem, sólidos solúveis, índice tecnológico, pH, acidez titulável, ratio e ácido ascórbico dos frutos). O tamanho, a cor da casca, o teor de sólidos solúveis e o pH do suco de lima ácida ‘Tahiti’ não foram influenciados pelas adubações com N e K2O. A espessura da casca, a porcentagem de suco e o índice tecnológico aumentaram com as doses de N e K2O aplicadas no solo. O volume de suco e a firmeza do fruto reduziram com as aplicações das doses de K2O. A acidez titulável e o teor de ácido ascórbico aumentaram com as doses de K2O. As diferentes doses de adubação nitrogenada e potássica influenciaram mais na qualidade do suco que nas características externas de lima-ácida ‘Tahiti’, em pós-colheita.

ABSTRACT This study aimed to evaluate external characteristics and juice obtained from ‘Tahiti’ acid lime produced under nitrogen and potassium fertilization. This study had a completely randomized design with three replicates of four fruits of the two central plants, 4 x 5 factorial and four N doses (0, 25, 50 and 100 Kg ha-1 year- 1) and five K2O doses (0, 25, 50, 100 and 200 Kg ha-1 year- 1), totaling 20 treatments. In the postharvest period, external characteristics (size, color and skin thickness, firmness and fresh mass) and juice (content, percentage, soluble solids, technological index, pH, titratable acidity, ratio and ascorbic acid) of fruits were evaluated. Size, skin color, soluble solids content and pH of ‘Tahiti’ acid lime juice were not affected by N and K2O fertilization. Skin thickness, juice percentage and technological index increased with the N and K2O doses applied to the soil. Juice content and fruit firmness decreased with application of K2O doses. Titratable acidity and ascorbic acid content increased with K2O doses. The different nitrogen and potassium doses influenced more the juice quality than the external characteristics of ‘Tahiti’ acid lime in the postharvest period.

En un cultivo de lima ácida Tahití Citrus latifolia Tanaka (Rutaceae) con siete años de edad ubicado en El Espinal, Tolima, Colombia, donde predomina un balance hídrico negativo durante todo el año, se evaluó el efecto del riego y la fertilización sobre el rendimiento y la calidad del fruto entre los años 2009 y 2011. Los árboles fueron sometidos a tres láminas de riego en función de la evapotranspiración de referencia (ETo): L1=100 %, L2=70 % y L3=50 %. A su vez, se aplicaron tres tratamientos de fertilización nitrogenada, así: N1=nivel de nitrógeno requerido según el balance nutricional, N2=el doble del nivel de nitrógeno usado para N1 y N3=fertilización del productor. Se evaluaron el rendimiento, el peso del fruto, el diámetro ecuatorial y polar del fruto, el grosor de la cáscara, el peso y el porcentaje de jugo, la acidez, los sólidos solubles y el contenido de vitamina C. El diseño experimental fue de bloques completos al azar en arreglo de parcelas divididas, los datos se analizaron estadísticamente con el paquete SAS, realizando análisis de varianza y comparación de medias. Se presentó una respuesta óptima en riego y calidad del fruto con la interacción riego L1 y la fertilización N2. Se obtuvieron los valores más altos en las variables de respuesta con la lámina de mayor agua aplicada L1, indiferente de la fertilización aplicada, lo que indica que un menor suministro de agua no solo afecta el rendimiento sino también la calidad y minimiza las oportunidades de mercado

In a seven years old citrus grove of Tahiti lime Citrus latifolia Tanaka (Rutaceae) located in El Espinal, Tolima, Colombia, which has a predominantly negative water balance throughout the year, we evaluated the effect of irrigation and fertilization on yield and fruit quality in 2009 and 2011. Trees were subjected to three levels of water based on the evapotranspiration reference (ETo): L1=100 %, L2=70 % and L3=50 %. We applied three nitrogen treatments: N1=nitrogen required by the nutritional balance, N2=twice the level of nitrogen used in N1, and N3=fertilizer application used by the common farmer. We evaluated the performance, fruit weight, polar and equatorial diameter of fruit, shell thickness, weight and percentage of juice, acidity, soluble solids and vitamin C. The experiment was conducted under a randomized complete block design in a split plot arrangement; the variance and means of the data were statistically analyzed with SAS. And optimal response is between irrigation and fruit quality interaction was obtained with irrigation L1 and fertilization N2. We obtained the highest values in the response variables when the highest amount of water was applied L1, regardless of fertilizer applications, indicating that a lower water supply not only affects the performance of the plant, but also the quality of the fruit, minimizing market opportunities.

The citrus acreage of Mexico exceeds 532 000 hectares. This area is endangered by the recent detection of the bacterium Candidatus Liberibacter asiaticus in some states and by the wide distribution of the vector Diaphorina citri. The aim of this study was to evaluate the efficiency against D. citri of chemical compounds applied to the soil and foliage in Persian lime. Two field evaluations were made during 2011 with applications of spirotetramat and imidacloprid to foliage and soil, and of spinosad and avermectin only to foliage. In the first evaluation, the spirotetramat (400 mL/ha) and the imidacloprid (300 mL ha-1), applied to foliage, caused a decrease of nymphs of 78.8%-93.54% three days after the application. The Imidacloprid (300 mL ha-1), applied to the soil, the spinosad (0.1 L ha-1), and the avermectin (0.1 L ha-1), had 69.8%, 70.6% and 61.6% less nymphs than the control treatment. In the second evaluation, imidacloprid, applied to the foliage, decreased the population of nymphs in shoots by 81.9%.The lowest average of nymphs per shoot in various sampling dates was obtained with the spirotetramat and imidacloprid treatments applied to foliage; 89.6% and 87.5% less than the control, respectively. Of the products evaluated, the spirotetramat and the imidacloprid, when applied to foliage, exerted the greatest effect against D. citri.

La superficie de cítricos en México es superior a 532 mil hectáreas. Esta área se encuentra en peligro por la reciente detección de la bacteria Candidatus Liberibacter asiaticus en algunos estados y por la amplia distribución del vector Diaphorina citri. El objetivo fue evaluar compuestos químicos aplicados al suelo y follaje contra D. citri en lima persa. Se hicieron dos evaluaciones en campo durante 2011. Con aplicaciones de espirotetramato e imidacloprid al follaje y al suelo y spinosad y avermectina sólo al follaje. En la primera evaluación, tres días después de la aplicación, el espirotetramato (400 mL/ha) e imidacloprid (300 mL ha-1) aplicados al follaje ejercieron una disminución de ninfas de 78.8% y 93.54%. El imidacloprid (300 mL ha-1) aplicado al suelo, spinosad (0.1 L ha-1) y avermectina (0.1 L ha-1), tuvieron 69.8%, 70.6% y 61.6% menos ninfas que el testigo. En la segunda evaluación, el imidacloprid aplicado al follaje disminuyó 81.9% la población de ninfas en brotes. El menor promedio de ninfas por brote en diversas fechas de muestreo se obtuvo con los tratamientos de espirotetramato e imidacloprid al follaje, 89.6% y 87.5% menos que el testigo, respectivamente. De los productos evaluados el imidacloprid y espirotetramato aplicados al follaje ejercieron mayor efecto contra D. citri.

La lima ácida Tahití, Citrus latifolia Tanaka (Rutaceae), es susceptible al daño del virus de la tristeza de los cítricos (CTV), lo que disminuye la rentabilidad del cultivo. En la terraza alta del piedemonte de Meta, Colombia, se evaluó la influencia del virus sobre el comportamiento de la lima ácida Tahití en seis patrones: Carrizo, Sunki × English, Sunki × Jacobson, Pomeroy, Rubidoux y Kryder 15-3. El diseño experimental utilizado fue completamente al azar tomando cada árbol como unidad experimental; se utilizó comparación de medias y estadística inferencial para: altura de la planta, diámetro y altura de la copa, volumen de la copa, producción y severidad del virus de la tristeza. La mayor producción acumulada por árbol (kg/árbol) la obtuvo Sunki × English; todos los patrones presentaron una altura homogénea, excepto Carrizo con menor tamaño y volumen de copa. La mayor producción de frutos acumulada durante ocho cosechas se obtuvo con Sunki × English seguido por Rubidoux y Carrizo. La mayor eficiencia productiva promedia se obtuvo con Sunki × Jacobson. La producción y el crecimiento morfológico decayeron en la séptima cosecha (2007) en todos los patrones, ocasionado por la infección de una mezcla de aislados de virus de la tristeza de los cítricos tipo Madeira y tipo B128 que ocasionan acanalamiento del tallo; tipo B31 que produce acanalamiento moderado; y aislamientos B7 y VT.

Tahiti lime, Citrus latifolia Tanaka (Rutaceae), is susceptible to Citrus Tristeza Virus (CTV), and if affected, decreases the profitability of the crop. In the well-drained high terrace of the Meta piedmont, the influence of the virus attack was evaluated on the performance of Tahiti lime grafted on six rootstocks (Carrizo; Sunki × English; Sunki × Jacobson; Pomeroy; Rubidoux, y Kryder 15-3) on a completely randomized experiment design taking each tree as an experimental unit. A comparison of means and inferential statistic were used for: plant height, height and canopy diameter; canopy volume, yield and severity of CTV. All rootstocks showed homogenous height. Carrizo was the exception with less size and canopy volume. The highest accumulated fruit yield (Kg/tree) was obtained by Sunki x English, followed by Rubidoux and the lowest yield was obtained by Carrizo. The highest yield efficiency of average canopy volume was obtained with Sunki x Jacobson. The Tahiti lime yield and morphological development fell in the seventh year (2007) in all rootstocks, due to an infection caused by a mix of isolates of CTV type Madeira and type B128, isolates which cause stem channeling: type B31 which causes moderate stem channeling and B7 and VT isolate.

Citrus crops represent an outstanding activity at worldwide level. Mexico ranks fourth place in production. Due introduction and dispersion of D. citri vector in all citric zones from Mexico and the newly detected disease known as huanglongbing (HLB) caused by Candidatus Liberibacter asiaticus bacteria, assessment of control methods for this bug is required. In 2010, technical effectiveness in field and persistence for different action route against Persian lime D. citri chemical products tests were performed in Nayarit, Mexico. Two assessments were made at different dates. The amount of nymphs per shoot and percentage of infested shoots were assessed in each rehearsal. From evaluated products, dimethoate, imidacloprid and the mixture of imidacloprid and (β-cyfluthrin exerted more than 85% percent of control against nymphs during 27 days after application. In trees treated with dimethoate and imidacloprid in 400 mL and 300 mL ha-1 dose, respectively, 100% of shoots free of D. citri nymphs at 27 days after application was observed. Agricultural oil in two and three L ha-1 dose exerted less control against D. citri nymphs.

A nivel mundial, la citricultura representa una actividad de gran importancia. México ocupa el cuarto lugar mundial en producción. Debido a la introducción y dispersión del vector D. citri en todas las zonas citrí colas de México y la reciente detección de la enfermedad conocida como huanglongbing causada por la bacteria Candidatus Liberibacter asiaticus, es necesaria la evaluación de métodos de control de este insecto. En el año 2010 en Nayarit, México, se realizaron pruebas de efectividad técnica en campo y persistencia de productos químicos de diferente mecanismo de acción contra D. citri en lima persa. Se hicieron dos evaluaciones en fechas distintas. En cada ensayo se evaluó número de ninfas por brote y porcentaje de brotes infestados. De los productos evaluados el dimetoato, imidacloprid y la mezcla de imidacloprid más betaciflutrina ejercieron más de 85 % de control de ninfas durante 27 días después de la aplicación. En los árboles tratados con dimetoato e imidacloprid en dosis de 400 mL y 300 mL ha-¹, respectivamente, se observó 100% de brotes libres de ninfas de D. citri a los 27 días después de la aplicación. El aceite agrícola en dosis de dos y tres L ha-1 ejerció menor control de ninfas de D. citri.

Este trabalho foi realizado com o objetivo de quantificar a necessidade de acúmulo de horas de frio para a floração da limeira ácida 'Tahiti', sem a aplicação de deficiência hídrica, além de avaliar as trocas gasosas e fluorescência da clorofila a em condições de baixa temperatura e baixa luminosidade. O experimento foi conduzido em Viçosa-MG, Brasil, com plantas de limeira ácida 'Tahiti', enxertadas sobre limoeiro 'Cravo', cultivadas em vasos de 12 litros. O delineamento utilizado foi o inteiramente casualizado, com sete tratamentos e quatro repetições, com uma planta por parcela. A partir do dia 01/02/2008 até o dia 30/04/2008, quatro plantas foram retiradas da câmara de crescimento (CC) (temperatura: 16/12°C (dia/noite); umidade relativa: 70%; fotoperíodo: 10 horas; densidade de fluxo de fótons fotossintéticos: 100µmol m-2 s-1) a cada 15 dias e levadas para a casa de vegetação (CV) sem controle ambiental, totalizando sete datas de transferência. A exposição de plantas a baixas temperaturas, sob condições controladas não causou alterações significativas nas características de fluorescência da clorofila a, mas causou redução de 80% nas trocas gasosas. Entretanto, essa redução não prejudicou a floração das plantas. As plantas expostas a condições não indutoras apenas emitiram brotações vegetativas, enquanto aquelas submetidas a baixas temperaturas, quanto maior foi o tempo de exposição, maior foi o número de flores emitidas.

The research was realized to quantify the need for accumulation hours under low temperatures to the acid lime 'Tahiti' flowering, without water application and beyond evaluating gas exchange and chlorophyll a fluorescence under low temperature and light. The experiment was conducted in Viçosa-MG, Brazil, with plants from acid lime 'Tahiti' grafted on Rangpur lime grown in pots of 12 liters. The design was completely randomized with seven treatments and four replicates with one plant per plot. From 02/01/2008 until 04/30/2008, four plants were taken from each growth chamber (CC) (temperatures: 16/12°C (day/night); air humidity: 70%; photoperiod: 10 hours; photosynthetic photon flux density: 100µmol m-2 s-1) to 15 days and taken to a greenhouse (CV) without environmental control, totaling seven dates of transfer. Exposure of plants to low temperatures, under controlled conditions, does not cause significant changes in the characteristics of chlorophyll a fluorescence, but caused 80% of reduction in gas exchange. This reduction does not hurt the flowering plants. Plants exposed to no-induced conditions only issued vegetative shoots, while those submitted to lower temperatures, the greater was the exposure time, the greater was the number of flowers sent.