Thysanoptera diversity associated with Mexican lemon (Citrus aurantifolia Christm.)

Objective: To calculate the monthly relative abundance of Thysanoptera species, according to the Margalef, Simpson and Shannon-Wiener diversity indices. Design / Methodology / Approach: The work was carried out in three geographic units with conventional management, during January-December, 2019 in the Reserva de la Biosfera Zicuirán-Infiernillo (Biosphere Reserve), Michoacán, Mexico. In each unit, 10 trees were selected through simple random sampling. Thrips counts were performed on ten shoots per tree every 15 d, for a total of 7200 shoots in the three geographic units. Thysanoptera individuals were placed in entomological jars. The variables were: number of thrips collected per shoot in sampled tree and geographic unit (orchard). To estimate the specific richness and structure of species, the program "calculation of diversity indices DIVERS" was used. Results: In the three geographical units studied, the recorded presence of Thysanoptera accounted for 12 to 17 species. For Nueva Italia 12 recorded species, two were permanent (16.66%), five abundant (41.66%), one scarce (8.3%) and four rare (33.33%). In Zicuirán, three species were permanent (17.64%), six abundant (35.29%), two scarce (11.76%) and six rare (35.29%). In Los Hoyos, four species were permanent (26.66%), four abundant (26.66%) and seven rare (46.66%). The abundance of species was represented by the genus Frankliniella and the species Scolothrips sexmaculatus and Scirtothrips citri. The highest species richness and abundance was found from January to May. In October and November, the value of the calculated indices was zero, which shows less richness and abundance of individuals. The best species uniformity was recorded during January and December, which meant a more stable and homogeneous relation. Study limitations/Implications. Pest resurgence, presence of Candidatus Liberibacter spp. and its vector Diaphorina citri. Findings / Conclusions: in Nueva Italia, 12 species were taxonomically determined; in Los Hoyos 15, and in Zicuirán 17 species, which are reported for the first time in the state of Michoacán, Mexico. At the geographic unit "Los Hoyos" diversity was higher, uniform and stable.

Tisanópteros asociados al limón mexicano (Citrus x aurantifolia (Christm) Swingle) en Apatzingán, Michoacán, México

Objetivo: determinar taxonómicamente las especies de tisanópteros en limón mexicano (Citrus x aurantifolia (Christm) Swingle), conocer su fluctuación y densidad poblacional, y calcular la interacción con la precipitación pluvial.Diseño/metodología/aproximación: Se utilizó un muestreo aleatorio simple. Las recolectasy muestreos fueron realizados cada 15 d, en diez árboles, y en diez brotes vegetativos. Las partes vegetativas fueron lavadas con una solución jabonosa, para separar a los trips, que fueron depositados en frascos entomológicos con alcohol a 70%. En total, se prepararon 375 micromontajes. La determinación taxonómica fue por comparación. Para conocer la 3 interacción de los tisanópteros con la precipitación pluvial, la información se analizó mediante un polinomio cuadrado, con el método RS REG. SAS.Resultados: Se obtuvieron 4968 tisanópteros. La especie Scolothrips sexmaculatus fuedominante, seguida de Scirtothrips citri, Frankliniella cephalica, y F. bispinosa. Seidentificaron cuatro especies depredadoras de ácaros y trips: Scolothrips sexmaculatus,Leptothrips mcconelli, Stomatothrips brunneus y Scolothrips palidus. Se encontró un ejemplaradulto del género Microcephalothrips sp. 1, dos individuos de los géneros Liothrips yMicrocephalothrips sp. 2 y siete del género Karnyothrips cuyas especies no se identificaron.Se detectó un pico en la fluctuación y densidad poblacional, que correspondió a los meses deenero a abril. El efecto de la precipitación pluvial fue determinante.Limitaciones del estudio/implicaciones: Inseguridad civil, y descapitalización del sistema producto limón.Hallazgos/conclusiones: En las tres localidades, se presentaron cinco especies dominantes: Scolothrips sexmaculatus, Scirtothrips citri, Frankliniella bispinosa, F. cephacilay F. curticornis.

Impacts of Fruit-Feeding Arthropod Pests on Oranges and Mandarins in California

One of the major challenges facing citrus integrated pest management (IPM) in California is the recent, sharp increase in the acreage of mandarins being planted. The current citrus IPM guidelines have been established from years of experiments and experience in oranges, with no specific guidelines for mandarins. In the absence of research into key arthropod pest effects in mandarins, the assumption that the pest management practices for oranges appropriately transfer for optimal production in mandarins has not been tested. We used a data mining or ‘ecoinformatics’ approach in which we compiled and analyzed production records collected by growers and pest control advisors to gain an overview of direct pest densities and their relationships with fruit damage for 202 commercial groves, each surveyed for 1–10 yr in the main production region of California. Pest densities were different among four commonly grown species of citrus marketed as mandarins (Citrus reticulata, C. clementina, C. unshiu, and C. tangelo) compared with the standard Citrus sinensis sweet oranges, for fork-tailed bush katydids (Scudderia furcata Brunner von Wattenwyl [Orthoptera: Tettigoniidae]), and citrus thrips (Scirtothrips citri Moulton [Thysanoptera: Thripidae]). Citrus reticulata had notably low levels of fruit damage, suggesting they have natural resistance to direct pests, especially fork-tailed bush katydids. These results suggest that mandarin-specific research and recommendations would improve citrus IPM. More broadly, this is an example of how an ecoinformatics approach can serve as a complement to traditional experimental methods to raise new and unexpected hypotheses that expand our understanding of agricultural systems.

Biological, environmental and socioeconomic threats to citrus lime production

Limes as a fruit crop are of great economic importance, key to Asian and South American cuisines and cultivated in nearly all tropical and subtropical regions of the world. Demand for limes is increasing, driven by World Health Organization recommendations. Pests and pathogens have significantly reduced global productivity, while changes in agronomic techniques aim to alleviate this stress. We present here a holistic examination of the major biotic (pests and pathogens) and abiotic (environment and socioeconomic) factors that presently limit global production of lime. The major producers of limes are India, China and Mexico, while loss of lime production in the United States from 2006 has led many countries in the Western Hemisphere (Mexico, Costa Rica and Brazil) to export primarily to the USA. The most widespread invertebrate pests of lime are Toxoptera citricida and Scirtothrips citri. Another insect, Diaphorina citri, vectors both Huanglongbing (HLB) and Witches Broom of Lime, which are particularly destructive diseases. Developing agronomic techniques focus on production of resistant and pathogen-free planting materials and control of insect vectors. HLB infects citrus in nearly all growing regions, and has been particularly devastating in Asian citrus. Meanwhile, Citrus tristeza virus has infected over 100 million citrus trees, mainly in the Americas and Mediterranean. Currently, Witches Broom Disease of Lime is localised to the Middle East, but recently it has been detected in South America. The range of its vectors (D. citri and Hishimonus phycitis) further raises concerns about the potential spread of this disease. Abiotic threats to lime production are also a significant concern; key areas of lime production such as Mexico, India and the Middle East suffer from increasing water stress and high soil salinity, which combined with invasive pests and pathogens, may eliminate lime production in these areas. To ensure future security in lime production, policy makers, researchers and growers will need to examine the potential of more resistant lime cultivars and establish novel areas of cultivation.