Resource relocations in relation to dispersal in Tetranychus ludeni Zacher

Life history strategies of a species may affect its invasion success. Here, we used a haplodiploid pest, Tetranychus ludeni Zacher (Acari: Tetranychidae), which is native to Europe but now cosmopolitan, to investigate its life history strategies in relation to its dispersal tendency and distance. We tested whether and how dispersal influenced survival, lifetime fecundity, age-specific reproduction, and life table parameters of mated females. We show that mated females did not trade off their survival and lifetime reproductive output with dispersal but adjusted their resource allocations during different reproductive stages depending on whether and how far they dispersed. Long-distance dispersers invested more in dispersal in their early life while resident mites and short-distance dispersers invested more in reproduction during their early life. These resource allocation strategies may allow long-distance dispersers to explore the novel environment more effectively without compromising lifetime reproductive fitness, contributing to the invasion success of T. ludeni.

Resistencia de cultivares de berenjena (Solanum melongena L.) a Tetranychus ludeni (Acari:Tetranychidae)

Introducción. La berenjena Solanum melongena L. (Solanales: Solanaceae), es uno de los cultivos de hortalizas más importantes del Caribe Colombiano. Cultivo afectado por el ácaro rojo Tetranychus ludeni (Acari:Tetranychidae) el cual causa pérdidas económicas asociadas al rendimiento y contaminación ambiental por sobredosificaciones de acaricidas, lo que repercute en la salud de los agricultores y su familia. Objetivo. Evaluar la resistencia de siete materiales de berenjena a infestaciones artificiales de T. ludeni en condiciones de campo e invernadero. Materiales y métodos. El estudio se desarrolló entre abril y octubre de 2017 en el Centro de Investigación Turipaná de la Corporación Colombiana de Investigación Agropecuaria (AGROSAVIA). Los genotipos evaluados fueron las variedades Corpoica C029, Corpoica C015, las accesiones C036, C025, C049, y los cultivares regionales Buelvas y González; en campo e invernadero bajo un diseño en bloques completos al azar en tratamientos con cuatro repeticiones. Resultados. Las pruebas de campo mostraron diferencias significativas en la densidad poblacional de ácaros entre los materiales (F=4,42; p<0,0004), donde C025 tuvo los mayores valores y Buelvas los menores. La prueba de invernadero reveló diferencias en la densidad poblacional de ácaros entre materiales, con mayor población el cultivar C036 y con menor Buelvas. Conclusiones. Los cultivares regionales Buelvas y González exhibieron resistencia contra T. ludeni, proporcionando evidencia que existió resistencia a T. ludeni en campo en los materiales regionales de berenjena del Caribe colombiano. Las pruebas bajo invernadero, con las mayores densidades del ácaro, ofrecieron mayor poder discriminatorio y se sugieren en la fase inicial de evaluación completa del banco de germoplasma. Se sugiere el uso del cultivar Buelvas como genotipo resiste y C036 como genotipo de referencia susceptible a T. ludeni en futuros ensayos experimentales. Buelvas se recomienda como genotipo de referencia en razón de la estabilidad de la resistencia que mostró en campo e invernadero y asociada a mayores rendimientos.

Spider mites (Acari: Tetranychidae) from Serbia: new species for the country and the Balkan Peninsula, with a key to all known Serbian species

Seven spider mite species were recorded for the first time in Serbia: Bryobia macedonica Hatzinikolis & Panou, 1996 and Bryobia querci Hatzinikolis & Panou, 1997 from Bryobiinae, and Eutetranychus orientalis Klein, 1936; Oligonychus bicolor Banks, 1894; Oligonychus platani McGregor, 1950 Tetranychus canadensis McGregor, 1950 and Tetranychus ludeni Zacher, 1913 from Tetranychinae. Together with previously reported data, these findings raise the number of known tetranychid species in Serbia to 44, the second highest number of spider mite species recorded in the Balkan countries. The records of O. bicolor and T. canadensis are also the first ones on the Balkan Peninsula. The most frequent species were T. ludeni and E. orientalis, found in 24 and 13 out of 57 sampling locations. Spider mites were recorded on host plants in four basic habitat types, but predominantly in cultivated habitats and woodlands. A total of 27 plant species from nine families were recorded as hosts for newly recorded spider mites, including 12 plant species as new hosts for four tetranychids, and three plant species as new hosts for the family Tetranychidae. Plant family Rosaceae had the highest number of new hosts (7) and harbored the highest number of spider mite species (5). Tetranychus ludeni had the highest number of host plants (11) with two plant species as its new hosts. Oligonychus bicolor was found on eight host plants including five new hosts for this species and one new host for the family Tetranychidae. The other two new hosts for the family Tetranychidae harbored O. platani and B. querci, respectively. Symptoms of heavy infestations by E. orientalis and T. ludeni were recorded on host plants in several locations.

ATIVIDADE ACARICIDA DE ÓLEOS ESSENCIAIS SOBRE Tetranychus ludeni (Zacher) (Acari: Tetranychidae) EM DUAS CULTIVARES DE ALGODOEIRO

O presente trabalho teve como objetivo avaliar os efeitos repelentes e as taxas de crescimento populacional de óleos essenciais de Corymbia citriodora, Ocimum basilicum e Myracroduon urundeuva sobre o ácaro vermelho Tetranychus ludeni (Zacher) em algodoeiro de fibra colorida. Para o teste de repelência, óleos de Corymbia citriodora, Ocimum basilicum e Myracroduon urundeuva foram testados em diferentes concentrações sobre fêmeas adultas de T. ludeni, assim como para o teste de crescimento populacional, onde as cultivares foram tratadas com óleos essenciais. O efeito repelente foi verificado para todos os óleos testados nas duas cultivares de algodão colorida. As taxas instantâneas de crescimento populacional para T. ludeni nas cultivares de algodoeiro BRS Verde e BRS Rubi foram todas positivas (ri> 0), indicando que a população está em estado ascendente, no entanto, a população cresceu a uma taxa menor quando comparada ao controle. Os óleos essenciais de C. citriodora, O. basilicum e M. urundeuva apresentam efeito acaricida e potencial controle alternativo de T. ludeni em algodoeiro de fibras coloridas sem causar danos ao algodoeiro.Palavras-chave: ácaro vermelho; algodão colorido; controle alternativo; taxa instantânea de crescimento; repelência. ACARICIDAL ACTIVITY OF ESSENTIAL OILS ON RED MITETetranychus ludeni (Zacher) (Acari: Tetranychidae) IN TWO COTTON CULTIVARS ABSTRACT: The objective of this work was to evaluate the repellent and population growth rates of essential oils of Corymbia citriodora, Ocimum basilicum and Myracroduon urundeuva on the red mite Tetranychus ludeni (Zacher) in cotton fiber. For the repellency test, oils of Corymbia citriodora, Ocimum basilicum and Myracroduon urundeuva were tested in different concentrations on adult females of T. ludeni, as well as for the population growth test, where the cultivars were treated with essential oils. The repellent effect was verified for all tested oils the two cultivars of colored cotton. The instant population growth rates for T. ludeni in the cultivars BRS Verde and BRS Rubi were all positive (ri> 0), indicating that the population is in an upward, however, the population grew at a lower rate when compared to the control. The essential oils of C. citriodora, O. basilicum and M. urundeuva have an acaricidal effect and potential alternative control of T. ludeni in cotton from colored fibers without causing damage to the cotton.Keywords: Red mite; colored cotton; essential oils; instant growth rate; repellency.

Preference of red mite Tetranychus ludeni Zacher (Acari: Tetranychidae) to sweet potato genotypes

Tetranychus ludeni damages the sweet potato. Pest development can vary between plant genotypes. The objective was to identify the preference of Tetranychus ludeni for Ipomoea batatas genotypes, from the germplasm bank at the Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM). Natural infestations of this mite were observed on 54 sweet potato genotypes in potted, in a greenhouse. Three mite-infested leafs of each genotype were collected and analyzed. The red mite showed different population density rate in genotypes. The BD 29 genotype was found to be highly susceptible, the BD 08, BD 57, BD 17 and Espanhola genotypes were moderately susceptible, and the others forty-nine genotypes showed low susceptibility to the mite.

Pathogenicity of Metarhizium anisopliae and Beauveria bassiana fungi to Tetranychus ludeni (Acari: Tetranychidae)

ABSTRACT The use of acaricides is the main control method for Tetranychus ludeni (Acari: Tetranychidae) in horticultural crops. This mite has been recorded causing damage to sweet potato (Ipomoea batatas L.). The use of pathogenic fungi is an alternative to chemical control. The objective was to evaluate the pathogenicity of the fungi Metarhizium anisopliae (Meetch) Sorok, and Beauveria bassiana (Bals.) Vuill. to phytophagous mite T. ludeni in sweet potato plants. Conidial suspensions of M. anisopliae and B. bassiana, at concentrations of 106 and 107 con.mL-1 were applied to sweet potato leaves. After 24 hours, five females of T. ludeni newly emerged were released on the leaves. The bioassay was arranged in a completely randomized design with factorial arrangement 2 × 2 (two species of fungi and two concentrations) plus the control (distilled water), with 10 repetitions per treatment. The evaluation consisted of observing of three biological parameters of the mite: mortality, oviposition, and repellency, after 24, 48, 72, and 96 hours of contact with the fungi. The isolates of M. anisopliae cause high mortality rates of T. ludeni in laboratory. Beauveria bassiana has the potential to suppress future generations of mite, reducing its oviposition rate. Repellency behavior was not observed.