Interspecific predation and cannibalism and associated rates of oviposition were assessed for adult female Metaseiulus occidentalis (Nesbitt) and Typhlodromus pyri Scheuten when provided non-limiting amounts of either eggs, larvae, protonymphs, or deutonymphs. Tests with all four stages of phytoseiids and larvae of Tetranychus urticae Koch were carried out at 25°C. At 15 and 12.5°C only larvae of phytoseiids and larvae of T. urticae were prey items. Predation by T. pyri was higher than M. occidentalis at 12.5 and 15°C, but more similar at 25°C. M. occidentalis did not feed appreciably on phytoseiid larvae at 15° and 12.5°C. Neither phytoseiid oviposited at 12.5°C when fed phytoseiid larvae, but T. pyri did at 15°C. We concluded that T. pyri was a more active predator at low temperatures and early-season predation on M. occidentalis immatures by T. pyri could contribute to displacement of M. occidentalis from apple orchards in western Oregon. The effects of prey species and prey density on the rates of inter- and intraspecific predation and oviposition of the two phytoseiid mite predators Metaseiulus occidentalis (Nesbitt) and Typhlodromus pyri Schueten were investigated through a series of laboratory experiments. Adult female predators were given mixed populations of phytoseiid larvae and larvae of a more preferred prey, the spider mite, Tetranychus urticae Koch, at different rates and proportions. T. pyri, more of a generalist predator, consistently showed higher rates of predation and cannibalism on phytoseiid immatures at most prey populations and proportions. Manly Preference Indices indicated that T. pyri switched to feed on phytoseiid immatures at higher population levels and proportions of T. urticae than did M. occidentalis. This ability to readily utilize phytoseiid immatures as prey indicated that maintaining both predators in a biological control program at low prey densities may require the use of active selective techniques that favour M. occidentalis. The differential impact of Zetzellia mali on the phytoseiids Metaseiulus occidentalis and Typhlodromus pyri was studied in laboratory experiments and by analysis of population data from experimental orchard plots containing either of the phytoseiid species, similar numbers of prey mites, and high or low populations of Z. mali. Five hypotheses were evaluated to explain why Z. mali had more impact on M. occidentalis in the field than on T. pyri.. Given equal opportunity, Z. mali adult females did not consume greater numbers of M. occidentalis eggs than T. pyri eggs nor did adult females of either phytoseiid species inflict greater mortality on Z. mali eggs or larvae through attack or consumption. There was no difference in the within tree association of Z. mali adult females with the eggs of either phytoseiid species nor were there differences in the way prey mites (all stages) were spatially partitioned between adult female Z. mali as compared with adults and deutonymphs of either of the two phytoseiids. The foraging area of adult female Z. mali and the oviposition locations of the two phytoseiids from both field and laboratory assessments were compared using spatial statistical procedures. M. occidentalis laid significantly more eggs in the primary foraging area of adult female Z. mali than did T. pyri. This spatial difference was the only factor tested which might explain the observed greater impact of Z. mali on M. occidentalis. Impact of these interspecific interactions and competition on the persistence of predatory mite guilds for the biological control of plant-feeding mites are discussed. / Graduation date: 1995

O cultivo de fruteiras vem cada vez mais ganhando espaço no Brasil, tanto para o mercado interno quanto para o mercado externo. Dentre as frutas produzidas para exportação, destacam-se a acerola e a goiaba. Contudo o conhecimento a fauna de ácaros que ocorrem nestes cultivos ainda é reduzido. Um dos objetivos do presente trabalho foi realizar o levantamento dos ácaros em pomares de aceroleira e goiabeiras produzidas em Campinas, Estado de São Paulo, dando-se ênfase aos ácaros Stigmaeidae. Outro objetivo foi a elaboração de uma lista das espécies de Stigmaeidae mundialmente conhecidas, com informações taxonômicas relevantes. O levantamento foi realizado em 2005 e 2006 através de amostragens mensais de folhas, ramos e frutos das 2 culturas. Foram coletados 13384 ácaros pertencentes a 27 espécies de 23 gêneros de 13 famílias. Os predadores mais diversos, freqüentes e abundantes pertencem à família Phytoseiidae. Apenas 2 espécies de Stigmaeidae foram encontradas, Zetzellia languida Gonzalez em aceroleira e Agistemus floridanus Gonzalez em goiabeira. As espécies fitófagas encontradas em ambas as culturas são comuns em muitos países. Nenhuma destas tem sido considerada como de ampla importância quarentenária ao redor do mundo. Para a elaboração da lista de espécies de Stigmaeidae, foram realizadas buscas em bancos de dados para a detecção de referências bibliográficas, reunindo informações taxonômicas sobre as 464 espécies conhecidas nesta família. O estudo das referências taxonômicas obtidas permitiu a caracterização dos gêneros desta família. O resultado destas atividades pode facilitar a identificação de ácaros desta família, facilitando a identificação dos gêneros correspondentes e a localização inicial da literatura pertinente das espécies de cada gênero. / Fruit production for local and foreign markets has become progressively more important in Brazil. Barbados cherry and guava are some of the most important fruits produced in Brazil for exportation. However, knowledge about the mite fauna on those crops is still scanty. One of the objectives of this work was to survey the mites found on Barbados cherry and guava produced in Campinas, State of São Paulo, for the foreign market, with emphasis on the Stigmaeidae. The other objective was the preparation of a list of the world species of Stigmaeidae, providing relevant taxonomic information about them. The survey was conducted in 2005 and 2006, taking monthly samples of leaves, branches and fruits of those crops. A total of 13384 mites were collected, belonging to 27 species of 23 genera and 13 families. The most diverse, frequent and abundant predators collected belong to the Phytoseiidae. Only 2 species of Stigmaeidae were collected, Zetzellia languida Gonzalez on Barbados cherry and Agistemus floridanus Gonzalez on guava. The phytophagous species found on both crops are commonly found in many countries. None of those has been considered of ample quarantine importance around the world. For the preparation of the list of stigmaeid species, a search of different data bases was conducted to detect relevant literature, gathering taxonomic information on the 464 species known in this family. The study of the gathered information allowed the characterization of the genera of this family. The results of those activities may greatly facilitate the identification of stigmaeid mites by facilitating the identification of the corresponding genera and the initial localization of the pertinent literature of the species of each genus.

Made available in DSpace on 2014-06-11T19:32:05Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-01-20Bitstream added on 2014-06-13T20:22:56Z : No. of bitstreams: 1 silva_mz_dr_jabo.pdf: 519881 bytes, checksum: 7fd0c464d822d7c709bf01217e3de340 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O Brasil é considerado o maior produtor e exportador citros. Embora competitiva, a citricultura brasileira é bastante vulnerável, em função da constante ameaça de pragas e doenças que, podem, em determinadas circunstâncias, tornaremse fatores limitantes a produção. Dentre as pragas de importância econômica para a citricultura, o ácaro Brevipalpus phoenicis (Geijskes) é apontado como uma das principais, sendo responsável por uma parcela significativa do custo da produção de citros no Brasil, devido à necessidade de freqüentes aplicações de acaricidas para o seu controle. Dentre os agentes de controle biológico, os ácaros das famílias Phytoseiidae e Stigmaeidae são os de maior importância. Os ácaros dessas famílias coexistem em diversas culturas, e freqüentemente promovem o controle biológico de ácaros-praga e interagem entre si através de competição por presas ou pela predação interespecífica. Assim sendo, o objetivo da pesquisa foi conhecer as possíveis interações entre os membros das diferentes espécies de ácaros presentes em pomares cítricos do Estado de São Paulo, além de avaliar o efeito de agrotóxicos sobre ácaros predadores (Phytoseiidae e Stigmaeidae) encontrados em citros, e estudar a viabilidade de uso de Neoseiulus californicus (McGregor) para o controle de B. phoenicis na cultura. Um dos possíveis problemas relacionados à liberação de ácaros predadores visando ao controle de ácaros-praga seria o fato de que estes inimigos naturais poderiam ser mortos devido à aplicação de agrotóxicos. A introdução de populações de fitoseídeos tolerantes ou resistentes a produtos químicos em agroecossistemas citrícolas, possibilitaria a manutenção de um ambiente favorável ao controle biológico exercido pelos predadores, mesmo diante da aplicação de agrotóxicos, sem o efeito negativo sobre a mortalidade... / Brazil is considered the world's largest citrus grower and orange juice exporter. Although it is competitive, the Brazilian citriculture is vulnerable, in function of constant threats from pests and diseases, which, in certain circumstances, may become limiting factors to the production. Among the pests of economic importance, the mite Brevipalpus phoenicis (Geijskes) is considered one of the main pests, responsible for a significant portion of citrus production cost in Brazil, because of the necessity of frequent acaricide applications for its control. Among the biological control agents, the mites of the families Phytoseiidae and Stigmaeidae are the most important. The mites of these families coexist on several crops, and frequently promote the biological control of pest mites and interact with each other through the competition for prey or by interspecific predation. Therefore, the objective of this research was to understand the possible interactions among members of different mite species present in citrus orchards in the State of São Paulo, as well as to evaluate the effect of pesticides on the predaceous mites found on citrus; and to study the viability of the use of Neoseiulus californicus (McGregor) for the control of B. phoenicis on this crop. One of the possible problems related to predaceous mite releases aiming at the control of pest mites is the fact that these natural enemies can be killed by the applications of pesticides. The introduction of populations of phytoseiid mites which are resistant or tolerant to pesticides in citrus agroecosystems may contribute to keep a favorable environment for the biological control exerted by the predators, even in conditions of pesticide applications, without the negative effect on the mortality of these natural enemies. A strain of N. californicus, collected from a strawberry field in Atibaia County, State of São Paulo, has shown... Complete abstract click electronic access below)

O cultivo de fruteiras vem cada vez mais ganhando espaço no Brasil, tanto para o mercado interno quanto para o mercado externo. Dentre as frutas produzidas para exportação, destacam-se a acerola e a goiaba. Contudo o conhecimento a fauna de ácaros que ocorrem nestes cultivos ainda é reduzido. Um dos objetivos do presente trabalho foi realizar o levantamento dos ácaros em pomares de aceroleira e goiabeiras produzidas em Campinas, Estado de São Paulo, dando-se ênfase aos ácaros Stigmaeidae. Outro objetivo foi a elaboração de uma lista das espécies de Stigmaeidae mundialmente conhecidas, com informações taxonômicas relevantes. O levantamento foi realizado em 2005 e 2006 através de amostragens mensais de folhas, ramos e frutos das 2 culturas. Foram coletados 13384 ácaros pertencentes a 27 espécies de 23 gêneros de 13 famílias. Os predadores mais diversos, freqüentes e abundantes pertencem à família Phytoseiidae. Apenas 2 espécies de Stigmaeidae foram encontradas, Zetzellia languida Gonzalez em aceroleira e Agistemus floridanus Gonzalez em goiabeira. As espécies fitófagas encontradas em ambas as culturas são comuns em muitos países. Nenhuma destas tem sido considerada como de ampla importância quarentenária ao redor do mundo. Para a elaboração da lista de espécies de Stigmaeidae, foram realizadas buscas em bancos de dados para a detecção de referências bibliográficas, reunindo informações taxonômicas sobre as 464 espécies conhecidas nesta família. O estudo das referências taxonômicas obtidas permitiu a caracterização dos gêneros desta família. O resultado destas atividades pode facilitar a identificação de ácaros desta família, facilitando a identificação dos gêneros correspondentes e a localização inicial da literatura pertinente das espécies de cada gênero. / Fruit production for local and foreign markets has become progressively more important in Brazil. Barbados cherry and guava are some of the most important fruits produced in Brazil for exportation. However, knowledge about the mite fauna on those crops is still scanty. One of the objectives of this work was to survey the mites found on Barbados cherry and guava produced in Campinas, State of São Paulo, for the foreign market, with emphasis on the Stigmaeidae. The other objective was the preparation of a list of the world species of Stigmaeidae, providing relevant taxonomic information about them. The survey was conducted in 2005 and 2006, taking monthly samples of leaves, branches and fruits of those crops. A total of 13384 mites were collected, belonging to 27 species of 23 genera and 13 families. The most diverse, frequent and abundant predators collected belong to the Phytoseiidae. Only 2 species of Stigmaeidae were collected, Zetzellia languida Gonzalez on Barbados cherry and Agistemus floridanus Gonzalez on guava. The phytophagous species found on both crops are commonly found in many countries. None of those has been considered of ample quarantine importance around the world. For the preparation of the list of stigmaeid species, a search of different data bases was conducted to detect relevant literature, gathering taxonomic information on the 464 species known in this family. The study of the gathered information allowed the characterization of the genera of this family. The results of those activities may greatly facilitate the identification of stigmaeid mites by facilitating the identification of the corresponding genera and the initial localization of the pertinent literature of the species of each genus.

Plant-feeding mites represent major pests in agriculture that are of importance to crops world-wide, as large populations of mites reduce the quality and quantity of yields. Alternatives to the use of pesticides are needed due to their negative effects and bio-control agents (predatory mites) remain advantages as they suppress spider mites and other plant pests. This study aims to determine species status of plant-feeding and predatory mites on plants of the family Solanaceae and to apply morphological and molecular data to determine phylogenetic relationships among economically important Phytoseiidae, Stigmaeidae and Tetranychidae. The material for this study was collected through plant beating and specimens were preserved in 75% and 96% ethanol respectively and mounted in Heinz’s PVA medium on microscope slides. A survey was conducted during peak seasons to provide enough samples of pest and predatory species. Morphological analysis was performed and initial results indicate that 94% of the species identified were parasitic and 6% were predatory, which led to a predator:prey ratio of 1:17, where Tetranychus evansi Baker & Pritchard had the highest frequency of appearance. A modified Qiagen DNeasy tissue kit extraction protocol was used and Polymerase Chain Reaction was performed to amplify ribosomal ITS and mitochondrial COI gene fragments. The nucleotide sequence of a 700-bp fragment for ITS was determined by direct sequencing as well as for a 700-bp and 800-bp fragments for COI. The resulting data included 4 isolates that corresponded morphologically and molecularly with Phytoseiidae and 10 with Stigmaeidae. The phylogenetic trees agreed with the morphological data. For species that lack morphological descriptions in GenBank and are not placed within expected clades, one has to accept the possibility of miss identification and highlights the need to combine morphological and molecular approaches to guarantee solid species diagnosis. Ultimately, Solanaceae contain various parasitic mites, but predators seem low in numbers. This could be problamatic in finding effective bio-control agents. / MSc (Zoology), North-West University, Potchefstroom Campus, 2015

Plant-feeding mites represent major pests in agriculture that are of importance to crops world-wide, as large populations of mites reduce the quality and quantity of yields. Alternatives to the use of pesticides are needed due to their negative effects and bio-control agents (predatory mites) remain advantages as they suppress spider mites and other plant pests. This study aims to determine species status of plant-feeding and predatory mites on plants of the family Solanaceae and to apply morphological and molecular data to determine phylogenetic relationships among economically important Phytoseiidae, Stigmaeidae and Tetranychidae. The material for this study was collected through plant beating and specimens were preserved in 75% and 96% ethanol respectively and mounted in Heinz’s PVA medium on microscope slides. A survey was conducted during peak seasons to provide enough samples of pest and predatory species. Morphological analysis was performed and initial results indicate that 94% of the species identified were parasitic and 6% were predatory, which led to a predator:prey ratio of 1:17, where Tetranychus evansi Baker & Pritchard had the highest frequency of appearance. A modified Qiagen DNeasy tissue kit extraction protocol was used and Polymerase Chain Reaction was performed to amplify ribosomal ITS and mitochondrial COI gene fragments. The nucleotide sequence of a 700-bp fragment for ITS was determined by direct sequencing as well as for a 700-bp and 800-bp fragments for COI. The resulting data included 4 isolates that corresponded morphologically and molecularly with Phytoseiidae and 10 with Stigmaeidae. The phylogenetic trees agreed with the morphological data. For species that lack morphological descriptions in GenBank and are not placed within expected clades, one has to accept the possibility of miss identification and highlights the need to combine morphological and molecular approaches to guarantee solid species diagnosis. Ultimately, Solanaceae contain various parasitic mites, but predators seem low in numbers. This could be problamatic in finding effective bio-control agents. / MSc (Zoology), North-West University, Potchefstroom Campus, 2015