Academic literature on the topic 'Diaspididae'

In many citrus areas around the world and within citrus-producing regions of Australia, the California red scale (CRS), Aonidiella aurantii (Maskell) (Hemiptera: Diaspididae), is considered the most important pests of citrus. The main biological control agents of Ao. aurantii in this zone are the parasitoid Aphytis melinus DeBach (Hymenoptera: Aphelinidae). In order to improve the biological control of Ao. aurantii several biotic and abiotic factors were studied, that may affect the efficiency of A. melinus in the laboratory and the field. More concretely, reproductive potential and age-specific fecundity schedules of Ao. aurantii were studied in the laboratory at constant temperatures (20, 23 and 27°C), while the biological parameters of its parasitoid A. melinus were conducted at 27°C. Results revealed that the net reproduction rate (Ro) was considerably higher for Ao. aurantii than A. melinus, which reached 28.14 at 27°C, indicating its high reproductive capacity. Moreover, the net reproduction rate obtained for A. melinus indicates a low substitution potential for each female having Ao. aurantii as a host under laboratory conditions. The intrinsic rate of increase (rm) of A. melinus (0.188 ♀/♀/day) was significantly greater than that of Ao. aurantii (0.080) at 27°C. Plants produce volatile organic compounds (VOCs) in response to herbivore attack, and these VOCs can be exploited by parasitoids of the herbivore as host location cues. The VOCs from non-infested and Ao. aurantii-infested citrus fruit were investigated using headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). The data showed that more than 52 different compounds were identified, and different emissions associated attributed to herbivore activity were found for all fruit species (lemon, orange, mandarin and Tahitian lime). However, a single compound was exclusively produced by infested lemon fruit, while two compounds were significantly increased, and two compounds were only present in non-infested lemon. Five compounds were significantly increased in infested mandarins. For orange, five compounds were increased, and five compounds were exclusively presented in infested fruit. For lime fruit, eighteen of these compounds were increased, one was decreased, whereas five compounds were produced exclusively from infested lime fruit. Two putative herbivores-induced plant volatiles, d-limonene and β-ocimene, were significantly increased by Ao. aurantii infestation in all infested fruit, regardless of the citrus species. Subsequently, the preferences of female parasitoid on infested or healthy fruit in olfactometer bioassays were evaluated. Then in order to understand the magnitude of volatile attractiveness, the innate attractiveness of VOCs to A. melinus females in varying densities were tested in the laboratory. The results of the olfactometer assays that tested the behaviour of A. melinus to the different compounds emitted from infested and non-infested citrus fruit showed no such preference when compared between non-infested and infested oranges, mandarins and lime fruit; whilst, there were significant preferences for lemon fruit infested with Ao. aurantii over non-infested ones. For assessment, the attraction of synthetic Herbivore induced plant volatiles (HIPVs), four different concentrations (5,10, 15 and 20 μl/ml) of d-l-limonene and β-ocimene were investigated. However, mated A. melinus females preferred the reward-associated VOC more than hexane control in the case of d-limonene at the tested dosages of 15 and 20 μl/ml, β-ocimene at tested dosages of 10, 15 and 20 μl/ml. Finally, this study evaluated the dispersal ability of released A. melinus adults and their effect on the parasitism percentage, using d-limonene and β-ocimene with yellow sticky traps and scoring percentage parasitism on infested fruit. Under field conditions, the natural enemies’ effectiveness in controlling pests is largely correlated with their capability to spread towards infested crops. In this study, d-limonene and β-ocimene were examined for their attractiveness to California red scale parasitoid A. melinus in the field after augmentative releases. Field experiments demonstrated that lures baited with isolates of d-limonene and\or β-ocimene, which significantly attracted some species of natural enemies but had no significant impact on others. The number of A. melinus captured during the whole trial was greater in the traps treated with volatiles than the control. Finally, the overall parasitism rates were not increased by synthetic HIPV lures, but there was evidence that lures may increase parasitism of California red scale when there is a decrease in the amount of volatile organic compounds due to lack of healthy and infested fruit. In conclusion, HIPVs can potentially play important roles in attracting and exploiting natural enemies to reduce pest infestations.

The scurfy scales in the genus Chionaspis comprise a unique taxon among the armored scale insect genera in North America. The taxonomic reviews of the species belonging to the genus by Cooley (1899) and Ferris (1937, 1942) are far outdated. The present research is a comprehensive review of all the species in this genus in North America, with special emphasis on polymorphism associated with feeding sites which has been discovered in some species. Seventeen species have been redescribed and illustrated in detail, each with a discussion of their morphological affinities and relationships. Their host habits and zoogeography are summarized. The five species having typical bark and leaf forms, as well as intermediate forms, are discussed in more detail. A separate chapter deals with polymorphism, including a historical literature review of the subject. A hypothesis is given on the modes of transfer from the bark form to the leaf form and vice versa, that results in different morphs in first or second generations. Two keys were prepared: one for the genera related to Chionaspis and another for the determination of the species of this genus in North America. The three species that have been recently redescribed, C. americana and C. kosztarabi and C. nyssae are also discussed, and the most important morphological characters and the plates prepared by the original authors for each of these three species are given in order to better utilize the key to the species in North America. As a direct result of this research, two new species have been discovered: Chionaspis gilli Liu and Kosztarab, and C. hamoni Liu and Kosztarab. In addition new morphs were found for C. platani and C. wistariae. This thesis also includes many new distribution and host records for several species. The phylogenetic relationship of all the species in this study has been discussed, and as a result of the Ward's Minimum Variance Cluster Analysis (1985 version, SAS), a dendrogram has been provided based on 23 numerical characters.<br>Master of Science

The eastern hemlock [Tsuga canadensis (L.) Carrière] is one of the native dominant forest components of northeastern US. At present, these valuable stands face an alarming decline, in part due to the Fiorinia externa, elongate hemlock scale (EHS), (Hemiptera: Coccoidea: Diaspididae). The armored shield of F. externa provides an excellent defense against insecticides, natural enemies and adverse conditions. Chemical and classical biocontrol methods have been unable to stop the spread of this pest. Recently, the occurrence of an epizootic within the F. externa population in the Mianus River Gorge Preserve in Bedford, NY revealed a promising opportunity for control of this scale. Entomopathogenic fungi represent a valuable, although under-utilized, group of organisms with unique capabilities for self-sustaining pest management. Given the significant impact of this epizootic on F. externa, we have conducted extensive research on the biology, genetics and biological control potential of this epizootic. We molecularly identified a complex of entomopathogenic, phytopathogenic, and endophytic fungi associated with the epizootic in 36 localities within the states of New York, Pennsylvania, Connecticut and New Jersey. One fungus, Colletotrichum sp., was the most commonly isolated organism in populations of F. externa within areas of the epizootic. The host range of this Colletotrichum species comprised both insects and plants, although diverse life cycles occured in the different hosts. Endophytic growth was observed in 28 species of plants comprising 18 families (52% of the sampling), whereas in F. externa biotrophic and necotrophic growth was detected. Colletotrichum is a widely known phytopathogenic genus and reports of entomopathogenic activity are extremely rare. In order to understand the biological processes involved in the host-pathogen interactions we quantified the pathogenicity and virulence of this Colletotrichum sp. to four insect families and six plants families as well as the occurrence of sexual recombination in this Colletotrichum sp., both in vitro and in planta. We observed that this Colletotrichum sp. displays a propensy to induce rapid disease and mortality in F. externa hosts. Phylogenetic analysis comprising six of the most commonly studied nuclear genes in molecular phylogenetics (D1/D2 domain of the 28 rDNA gene, ITS region, β-Tubulin 2, GPDH gene, GS gene and HMG box at the MAT1-2 mating-type gene) and RAPDs showed this fungus is closely related to phytopathogenic strains of Colletotrichum acutatum and that it may represent a single population lineage of this species (i.e., Colletotrichum acutatum forma specialis fiorinia). Though a large body of information exists regarding the phytopathogenic genus Colletotrichum, ours is only the second reported entomopathogenic strain. It is not clear whether the colonization of an insect by this fungus is truly rare or a common but undetected event. Sexual recombination, observed in planta and in vitro, could be the means by which new genetic variants are generated leading to new biotypes with a selective advantage to colonize new hosts, which in this case is a novel host in a different kingdom.

El uso de pesticidas en la agricultura es todavía imprescindible para conseguir un control adecuado de las plagas. Con el fin de disminuir y controlar los riesgos que conlleva su aplicación existe una elevada presión social que promueve el desarrollo de acciones destinadas a minimizar el impacto de los pesticidas sobre el medioambiente. Una forma de conseguirlo es racionalizar la aplicación de los pesticidas, adecuando la cantidad de producto empleada a las necesidades reales y las condiciones particulares de la aplicación a realizar (plaga que se trata de controlar, maquinaria y productos empleados y vegetación sobre la que se aplica). Sin embargo, en la actualidad se utiliza una gran cantidad de producto con el objetivo de asegurar su resultado, sin tener en cuenta que a menudo se generan excesos innecesarios que acaban contaminando el medio ambiente y reduce el beneficio económico. Para poder ajustar racionalmente la cantidad de producto que debe aplicarse en un tratamiento, es necesario estudiar las relaciones existentes entre la cantidad de materia activa depositada, la forma en que se deposita y cómo ésta afecta al control de la plaga, evaluando las posibles diferencias de sensibilidad entre los estadios de desarrollo de la misma. Esta tesis ha servido para desarrollar de manera científica estas relaciones, utilizando como ejemplo el control del piojo rojo de California, Aonidiella aurantii Maskell (Hemiptera: Diaspididae) en sus distintas fases de desarrollo, ya que es una plaga de gran importancia en el cultivo de los cítricos. A lo largo de la misma se han utilizado los dos tipos de productos que más se emplean contra esta plaga, producidos a base de organofosforados y de aceites minerales. Como consecuencia de los modelos de respuesta que se han establecido en la tesis, se deducen los depósitos mínimos que se deben alcanzar sobre el material vegetal para obtener la máxima eficacia sobre cada estadio de desarrollo del insecto. Así, contra las fases jóvenes es necesario un depósito mínimo de caldo de 1.01 µl/cm2 con insecticidas organofosforados y de 3.41-4.72 µl/cm2 en el caso de los aceites minerales, mientras que para fases adultas estos depósitos aumentan hasta valores de alrededor de 4.72 µl/cm2 en todos los casos. A continuación se han validado en condiciones de campo los modelos de respuesta de los insecticidas. Para ello se han diseñado unos tratamientos en función del modelo de respuesta, el tamaño de la copa y la densidad foliar de la vegetación, y se ha comparado su eficacia respecto a tratamientos convencionales basados en volúmenes cercanos al punto de goteo. A pesar de haber obtenido menores recubrimientos con los tratamientos diseñados (60-70% frente al 90% con los tratamientos convencionales), no se han encontrado diferencias de eficacia estadísticamente significativas y se ha ahorrado alrededor de un 40% de producto fitosanitario. La tesis también demuestra que, una vez alcanzado un determinado umbral (diferente para cada estadio de la plaga), la generación de mayor recubrimiento no conduce a una mayor eficacia, poniendo de manifiesto que la cantidad de insecticida organofosforado o aceite mineral empleada puede ser reducida mediante la optimización del volumen de aplicación, basándose en el volumen de vegetación al que se dirige el tratamiento. Por último, la tesis propone y valida un método para estimar la calidad de un tratamiento, basado en los depósitos conseguidos sobre papel hidrosensible tras la aplicación. Para ello utiliza los datos de recubrimiento observados y los relaciona con la eficacia esperada.<br>Garcerá Figueroa, MDLC. (2013). Racionalización de las aplicaciones de productos fitosanitarios para el control de Aonidiella aurantii Maskell (Hemiptera: Diaspididae) en cítiricos [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/31666<br>TESIS

Foi feita uma revisão bibliográfia sobre a aplicação da amostragem seqüencial em manejos de pragas. A metodologia para o desenvolvimento de planos de amostragem seqüencial, foi baseada na teoria de Wald. Verificou-se que a distribuição binomial ajustou-se aos dados de presença-ausência da cochonilha-branca Aulacaspis tubercularis na cultura da manga, obtidos em duas propriedades localizadas na região de Jaboticabal, interior do estado de São Paulo. Seis planos de amostragem seqüencial foram elaborados para o monitoramento dessa praga, três com níveis de erros iguais a 0; 20 e outros três com níveis de erros iguais a 0; 10. Dentre esses, foram elaborados: dois planos para a amostragem em ramos durante o período vegetativo, dois para a amostragem em ramos durante o período de frutificação e outros dois planos para a amostragem em frutos. Nos planos de amostragem seqüencial para ramos no período vegetativo foram utilizados níveis de segurança iguais a 0; 35 e níveis de dano econômico iguais a 0; 50. Já no período de frutificação, houve um rigor maior quanto ao uso desses níveis, devido à presença de frutos. Foram utilizados níveis de segurança iguais a 0; 20 para ramos e 0; 05 para frutos, e níveis de dano econômico iguais a 0; 30 e 0; 15 para ramos e frutos, respectivamente. Foram construídas tabelas para o processo de amostragem em campo, facilitando assim, o trabalho do amostrador. Com o uso dessas tabelas o produtor poderá decidir rapidamente se há, ou não, a necessidade de se realizar o controle dessa praga.<br>A bibliographical revision on the application of the sequential sampling in management of pests was made. The methodology for the development of plans of sequential sampling, was based on the theory of Wald. It was verified that the binomial distribution adjusted to data of presence-absence of the mango scale Aulacaspis tubercularis on mango crop, gotten in two properties located at the region of Jaboticabal, interior of the state of São Paulo. Six plans of sequential sampling was elaborated for the monitoring of this pest, three with errors levels equal to 0; 20 and others three with errors levels equals to 0; 10. Amongst these, they was elaborated: two plans for the sampling in branches during the vegetative period, two for the sampling in branches during the period of fructification and others two plans for the sampling in fruits. In the plans of sequential sampling for branches in the vegetative period security level equal to 0; 35 and economic damage level equal to 0; 50 had been used. Already in longer period of fructification, had a bigger severity how much to the use of these levels, due to presence of fruits. Security levels equals to 0; 20 for branches and 0; 05 for fruits, and economic damage levels equals to 0; 30 and 0; 15 for branches and fruits, respectively, had been used. Tables for the sampling process in field, thus facilitating, the sampler's work was constructed. With the use of these tables the producer will be able to decide quickly has itself, or not, the necessity of if carrying through the control from this pest.

Pinnaspis aspidistrae (Signoret, 1869) (Homoptera, Diaspididae) é uma praga importante em citros no Brasil. Entretanto as pesquisas a respeito desta praga são escassas, particularmente em nossas condições. Portanto, desenvolveu-se estudos sobre a biologia, predadores e controle químico desta cochonilha, e também os efeitos de inseticidas em Cycloneda sanguinea (Linnaeus, 1763), predador freqüente nos pomares citricos. Os experimentos foram desenvolvidos no Departamento de Entomologia da Escola Superior de Agricultura"Luiz de Queiroz", Universidade de São Paulo Pinnaspis aspidistrae foi criada em hospedeiros do gênero Cucurbita em laboratório. Os inseticidas foram testados para o segundo e terceiro estádios ninfais de machos e fêmeas da cochonilha, para os quais utilizou-se colonias da praga em discos de folha de citros em placas de Petri e em aboboras. Os resultados foram os seguintes: Pinnaspis aspidistrae é uma espécie ovipara e apresenta uma reprodução anfigônica; os períodos de longevidade médios foram 59, 17 &#177; 0,92 dias na estação mais quente e 71,37 &#177; 1,40 dias na estação mais fria; O número médio de gerações anuais é 5,6; Os coccinelideos predadores da cochonilha foram Exoplectra sp., Scymnus sp. e Stethorus sp., além do crisopideo Chrysopa sp.; óleo mineral e carbofenotion apresentaram baixa toxicidade e abamectin foi seletivo quando aplicados sobre os adultos de Cycloneda sanguinea; óleo mineral, carbofenotion e abamectin foram seletivos e dimetoato medianamente tóxico aos predadores, quando estes foram colocados sobre o substrato previamente tratado com aqueles inseticidas; dimetoato e as misturas de azinfos etil, diazinon e carbofenotion com óleo mineral foram eficientes no controle dos dois instares ninfais da cochonilha, independentemente do sexo; óleo mineral, dimetoato e carbofenotion devem ser usados para o controle integrado de Pinnaspis aspidistrae , não somente por serem eficientes mas também porque preservam os coccinelideos predadores<br>Pinnaspis aspidistrae (Signoret, 1869) (Homoptera, diaspididae) is an important citrus pest in Brazil. However, researches concerning this insect are scarce, particularly in Brazil. Therefore, studies were developed on the biology, predators and chemical control of this pest and also the effects of inseticides on Cyeloneda sanguinea (Linnaeus, 1763) which is frequent predator in orchards. The experiments were set at the Departament of Entomology of"Escola Superior de Agricultura Luiz de Queiroz", University of São Paulo, in Piracicaba, State of São Paulo, Brazil. Pinnaspis aspidistrae was reared on cucurbit hosts in the laboratory. The insecticides were tested on second and third nymphal instars of male and female of the scale which were kept on discs of citrus leaves in petri dishes and on pumpkins. The results were as follows: Pinnaspis aspidistrae is an oviparous species and presents amphigen reproduction; the mean longevity periods were 59,17 &#177; 0,92 days in the hot season and 71,37 &#177; 1,40 days in the cold season; the mean number of generation per year is 5,6; the coccinellid predators of the scale were Exoplectra sp., Scymnus sp. and a Stethorus sp., as well as the chrisopid Chrysopa sp.; as to the effects of chemicals on Cycloneda sanguinea mineral oil and carbophenothion presented low toxicity while abamectin was selective to this predators. Mineral oil, carbophenothion and abamectin were selective and dimethoate presented median toxicity to Cycloneda sanguinea, when the predator was placed on substratum previously treated with those chemicals; dimethoate and mixture of azinphos ethil, diazibon and carbophenothion with mineral oil were efficient to control the second and third nymphal instars of the pest regardless the sex; mineral oil, dimethoate and carbophenothion should be used on the integrated control of Pinnaspis aspidistrae not only because they provide a good control of the pest, but also because they preserve the coccinellid predators.

En muchas áreas citrícolas del mundo el piojo rojo de California (PRC), Aonidiella aurantii (Hemiptera: Diaspididae), está considerado una plaga clave. En el Este de España se ha extendido durante las últimas décadas hasta cubrir una amplia extensión de cítricos. El control químico es difícil y frecuentemente es seguido de infestaciones recurrentes en poco tiempo, de la aparición de resistencias a diferentes productos usados para su control y de la eliminación de enemigos naturales en el campo. La mejora del manejo integrado y las técnicas de control biológico del PRC requieren conocer la composición de los enemigos naturales en cada zona climática, la fluctuación en su abundancia estacional, los niveles de parasitismo y depredación, como se distribuyen en la planta y como son afectados por el clima y el cambio climático. Aunque mucho se ha estudiado en laboratorio sobre los parasitoides Aphytis (Hymenoptera: Aphelinidae), los principales agentes de control del PRC, todavía no se conoce qué combinación de enemigos naturales consigue el mejor nivel de control en el campo, cómo varían los niveles de parasitismo a lo largo del año o cómo los parasitoides se distribuyen y compiten en el campo en relación con el clima. La acción de los Aphytis, ectoparasitoides, es complementada en muchas zonas citrícolas por los endoparasitoides Comperiella bifasciata y Encarsia perniciosi (Hymenoptera: Aphelinidae), los cuales pueden parasitar estadíos diferentes a Aphytis. Muy poco se sabe sobre el comportamiento y las respuestas biológicas bajo diferentes condiciones climáticas de estos endoparasitoides. Del mismo modo, el efecto de los depredadores sobre la población del piojo ha sido raramente estudiado. Actualmente, A. melinus, una especie introducida en el Este de España y el competidor superior, ha desplazado al parasitoide nativo A. chrysomphali de las zonas cálidas y secas ya que puede tolerar mejor las temperaturas cálidas del verano.<br>Sorribas Mellado, JJ. (2011). Biological control of California red scale, Aonidiella aurantii (Hemiptera: Diaspididae): spatial and temporal distribution of natural enemies, parasitism levels and climate effects [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/14794<br>Palancia

The California red scale Aonidiella aurantii is considered a key citrus pest. Parasitoids of genus Aphytis are the most important natural enemies of A. aurantii. In the Mediterranean basin, the native A. chrysomphali and the introduced A. melinus are the most abundant parasitoids of A. aurantii. The introduced has completely displaced the native A. chrysomphali in the south, whereas they coexist in the north-east of the Iberian Peninsula. We have used this well-known host-parasitoid system to investigate some gaps on the behavioural ecology of hymenopteran parasitoids, which have been exposed in the introduction. This knowledge will contribute to improve their use in biological control programs, especially in the case of A. aurantii in the Mediterranean basin.<br>El piojo rojo de California, Aonidiella aurantii, se considera una de las plagas de los cítricos más importante a nivel mundial. Los principales enemigos naturales de A. aurantii son los parasitoides del género Aphytis, siendo los más abundantes en la cuenca mediterránea el nativo Aphytis chrysomphali y el introducido A. melinus. En las zonas del sur de la Península Ibérica, A. melinus ha desplazado completamente al nativo A. chrysomphali, mientras que en el noreste ambos parasitoides coexisten. Durante el desarrollo de esta tesis, hemos utilizado este conocido sistema de parasitoides-hospedante para investigar algunos aspectos poco conocidos en la ecología del comportamiento de los parasitoides himenópteros, los cuáles han sido mencionados en la introducción de la tesis. Este conocimiento contribuirá a mejorar su uso en programas de control biológico, especialmente en el caso de A. aurantii en la cuenca mediterránea.