I compared the strength of bottom- up and top-down effects on insect herbivores along a natural salinity gradient in salt marsh communities in West - Central, Florida. I used a 2x2 factorial design with plots divided into four different treatments: 1) fertilizer applied to increase plant quality 2) sticky traps added to remove natural enemies (parasitoids) 3) fertilizer applied and sticky traps added and 4) control plots. These plots were placed on 7 different sites containing the salt marsh plant Borrichia frutescens along a natural stress salinity gradient. In each plot I determined the abundance of the sap sucker Pissonotus quadripustulatus, the gall maker Asphondylia borrichiae, spiders and the number of chewed leaves and bored stems. I also recorded leaf area, plant density, plant height and foliar nitrogen. Plants in fertilized plots exhibited increased height, density and leaf area.

Resistance development and possible non–target effects have been of concern since the first deployment of genetically modified crops with insecticidal properties. It is especially at the third trophic level and with important predators such as lacewings (Chrysoperla spp.) (Neuroptera: Chrysopidae) where negative effects of Cry 1Ab protein could have adverse effects in agro–ecosystems. Monitoring of the effect of genetically modified Bt maize on non–target organisms is required by law in South–Africa. Neuroptera are excellent indicators of environmental and habitat transformation, and also include key species for signifying areas and faunas that require priority protection. Monitoring techniques, especially for insect eggs, are often labour intensive and time consuming. A study was conducted to determine the preferred oviposition site of Chrysoperla spp. on maize plants to facilitate time–effective searching for eggs of these beneficial insects. Furthermore we determined if the presence of aphids on plants influenced Chrysoperla spp. oviposition preference. Another study was conducted to evaluate the effect of indirect exposure of C. pudica to Cry 1Ab protein, through healthy Bt–maize feeding prey, on its biology. Daily flight activity patterns and the height at which chrysopid adults fly above the crop canopy were also determined, as well as the movement of adult Chrysoperla spp. between maize fields and adjacent headlands. A clear spatial oviposition pattern was observed on maize plants and oviposition was not random as reported in earlier studies. This data facilitates rapid monitoring of the presence of eggs in maize cropping systems and is also of use in general pest management. Choicetest data showed that females responded positively to host plants that were infested with aphids. Feeding studies in which C. pudica larvae were indirectly exposed to Bt–toxin at the 3rd trophic level, showed a limited effect of Bt–toxin on only a few of the parameters that were evaluated. The pupal period and percentage adult emergence of larvae exposed to an unusually high amount of Bt–toxin was significantly shorter and lower respectively than that of the control group. The overall result of this study, in which the possible effect of food quality (prey) was excluded, showed that Cry 1Ab protein had an adverse affect only on certain fitness components during the life cycle of C. pudica. However, since this study represented a worst–case scenario where diverse prey was not available to C. pudica, negligible effects is expected under field conditions where prey is more diverse. It was determined that chrysopids was most active between 16:00 – 23:00 and that they fly largely between 0.5 m – 2.5 m above ground level. An attempt was also made to quantify migration between different vegetations types. This part was terminated because of bad weather conditions at several occasions when the experiment was attempted. Chrysopids were never present in grassland vegetation, but an adjacent lucerne field maintained a large population. As the maize crop developed chrysopid population numbers increased inside the field, presumably originating from the lucerne field. / Thesis (M.Sc (Environmental Science))--North-West University, Potchefstroom Campus, 2011.

Resistance development and possible non–target effects have been of concern since the first deployment of genetically modified crops with insecticidal properties. It is especially at the third trophic level and with important predators such as lacewings (Chrysoperla spp.) (Neuroptera: Chrysopidae) where negative effects of Cry 1Ab protein could have adverse effects in agro–ecosystems. Monitoring of the effect of genetically modified Bt maize on non–target organisms is required by law in South–Africa. Neuroptera are excellent indicators of environmental and habitat transformation, and also include key species for signifying areas and faunas that require priority protection. Monitoring techniques, especially for insect eggs, are often labour intensive and time consuming. A study was conducted to determine the preferred oviposition site of Chrysoperla spp. on maize plants to facilitate time–effective searching for eggs of these beneficial insects. Furthermore we determined if the presence of aphids on plants influenced Chrysoperla spp. oviposition preference. Another study was conducted to evaluate the effect of indirect exposure of C. pudica to Cry 1Ab protein, through healthy Bt–maize feeding prey, on its biology. Daily flight activity patterns and the height at which chrysopid adults fly above the crop canopy were also determined, as well as the movement of adult Chrysoperla spp. between maize fields and adjacent headlands. A clear spatial oviposition pattern was observed on maize plants and oviposition was not random as reported in earlier studies. This data facilitates rapid monitoring of the presence of eggs in maize cropping systems and is also of use in general pest management. Choicetest data showed that females responded positively to host plants that were infested with aphids. Feeding studies in which C. pudica larvae were indirectly exposed to Bt–toxin at the 3rd trophic level, showed a limited effect of Bt–toxin on only a few of the parameters that were evaluated. The pupal period and percentage adult emergence of larvae exposed to an unusually high amount of Bt–toxin was significantly shorter and lower respectively than that of the control group. The overall result of this study, in which the possible effect of food quality (prey) was excluded, showed that Cry 1Ab protein had an adverse affect only on certain fitness components during the life cycle of C. pudica. However, since this study represented a worst–case scenario where diverse prey was not available to C. pudica, negligible effects is expected under field conditions where prey is more diverse. It was determined that chrysopids was most active between 16:00 – 23:00 and that they fly largely between 0.5 m – 2.5 m above ground level. An attempt was also made to quantify migration between different vegetations types. This part was terminated because of bad weather conditions at several occasions when the experiment was attempted. Chrysopids were never present in grassland vegetation, but an adjacent lucerne field maintained a large population. As the maize crop developed chrysopid population numbers increased inside the field, presumably originating from the lucerne field. / Thesis (M.Sc (Environmental Science))--North-West University, Potchefstroom Campus, 2011.

Submitted by Milena Rubi (milenarubi@ufscar.br) on 2017-08-08T17:44:33Z No. of bitstreams: 1 GHIOTTO_Thais_2016.pdf: 18907197 bytes, checksum: 0779f8ac869df152bdd7747df97a15e5 (MD5) / Approved for entry into archive by Milena Rubi (milenarubi@ufscar.br) on 2017-08-08T17:44:43Z (GMT) No. of bitstreams: 1 GHIOTTO_Thais_2016.pdf: 18907197 bytes, checksum: 0779f8ac869df152bdd7747df97a15e5 (MD5) / Approved for entry into archive by Milena Rubi (milenarubi@ufscar.br) on 2017-08-08T17:44:49Z (GMT) No. of bitstreams: 1 GHIOTTO_Thais_2016.pdf: 18907197 bytes, checksum: 0779f8ac869df152bdd7747df97a15e5 (MD5) / Made available in DSpace on 2017-08-08T17:44:55Z (GMT). No. of bitstreams: 1 GHIOTTO_Thais_2016.pdf: 18907197 bytes, checksum: 0779f8ac869df152bdd7747df97a15e5 (MD5) Previous issue date: 2016-05-09 / Não recebi financiamento / Megastigmus transvaalensis is an exotic wasp that attacks Brazilian pepper tree drupes Schinus terebinthifolius in native forests and areas of restoration and ecological restoration in Brazil. The parasitism begins with the oviposition M. transvaalensis in drupes S. terebinthifolius where the larvae hatch and remain internally feeding of nutrients and tissue, affecting germination. The aim of this work was to study the effect of temperature, rainfall and humidity in the population dynamics of M. transvaalensis and determine the parasitism rate and sex ratio of this wasp in drupes S. terebinthifolius. The study was performed with yellow sticky traps and collection of S. terebinthifolius drupes in seasonal semideciduous forest during August 2014 to September 2015, in the region of Sorocaba, São Paulo, Brazil. The capture of insects through the sticky traps proved satisfactory, and thus can be applied to the monitoring of small Hymenopteros. Populations of M. transvaalensis were negatively correlated with the maximum temperature and population peak in the fall of 2015, meaning that when the maximum temperature has reduced, there is a higher incidence of insect field. The parasitism rate of S. terebinthifolius drupes ranged from zero to 36.34% during this period, making this value an aggravating factor for the emergence of new individuals, since this phytophagous wasp has the potential to be spread throughout Brazil and It poses a threat to the natural regeneration of S. terebinthifolius. The sex ratio of M. transvaalensis was 0.42 and 0.08 in the laboratory field. The bio-ecology and the damage caused by M. transvaalensis in drupes S. terebinthifolius warrant further studies to integrated management / Megastigmus transvaalensis é uma vespa exótica que ataca drupas de aroeira-pimenteira Schinus terebinthifolius em florestas nativas e em áreas de recomposição e restauração ecológica no Brasil. O parasitismo inicia com a oviposição de M. transvaalensis nas drupas de S. terebinthifolius, onde as larvas internamente eclodem e permanecem alimentando-se dos nutrientes e tecidos, prejudicando a germinação. O objetivo desse trabalho foi estudar o efeito da temperatura, precipitação e umidade na flutuação populacional de M. transvaalensis e determinar o índice de parasitismo e razão sexual dessa vespa nas drupas de S. terebinthifolius. O estudo foi realizado com armadilhas adesivas amarelas e coleta de drupas de S. terebinthifolius em fragmento de floresta estacional semidecidual, durante agosto de 2014 a setembro de 2015, na região de Sorocaba, São Paulo, Brasil. A captura dos insetos através das armadilhas adesivas se mostrou satisfatória, podendo assim ser aplicada para o monitoramento de pequenos Hymenopteros. As populações de M. transvaalensis apresentaram correlação negativa com a temperatura máxima e pico populacional no outono de 2015, significando que, quando a temperatura máxima apresenta redução, há maior incidência do inseto em campo. O índice de parasitismo das drupas de S. terebinthifolius variou de zero a 36,34% no período avaliado, tornando este valor um agravante para o surgimento de novos indivíduos, uma vez que, essa vespa fitófaga tem potencial de ser disseminado por todo Brasil e representa ameaça para a regeneração natural de S. terebinthifolius. A razão sexual de M. transvaalensis foi de 0,42 no laboratório e 0,08 em campo. A bioecologia e os danos causados por M. transvaalensis em drupas de S. terebinthifolius justificam mais estudos visando o manejo integrado dessa vespa fitófaga.

Delottococcus aberiae (Hemiptera: Pseudococcidae) es un pseudocóccido invasor originario del África subsahariana que fue detectado causando graves daños en cítricos del este de España en el año 2009. Debido al desconocimiento existente sobre esta especie, la gestión de D. aberiae se ha llevado a cabo mediante el uso de tratamientos químicos autorizados contra este tipo de insectos. Sin embargo, la última Directiva Europea (2009/128/EC) sobre el uso sostenible de productos fitosanitarios estipula que la aplicación de plaguicidas en el ámbito agrícola debe reducirse, promoviendo estrategias de manejo más sostenibles como es la aplicación del control biológico de plagas. Además, cuando una especie invasora llega por primera vez a un territorio es necesario estudiar su biología, comportamiento, daños causados y posibilidades de control. En esta tesis se presentan por primera vez estos estudios de biología y comportamiento de la plaga así como un análisis de los daños producidos por D. aberiae. También se han realizado estudios con el objetivo de implementar la aplicación de un programa de control biológico clásico sobre esta especie en cítricos en España. Para analizar la biología y comportamiento de D. aberiae se han muestreado durante tres años varias parcelas de cítricos con poblaciones de D. aberiae en la Comunidad Valenciana. En estas parcelas se han recogido muestras y contabilizado todos los pseudocóccidos presentes, su estadío de desarrollo y el estrato y órgano del árbol donde se encontraban. El periodo de daños al fruto fue estudiado en semicampo y campo mediante la infestación artificial con D. aberiae de frutos de distintos tamaños de diámetro. Por último se estudió el comportamiento y las posibilidades de control biológico de D. aberiae muestreando diversas parcelas de cítricos en su zona de origen (Sudáfrica). Los resultados mostraron que la abundancia de las poblaciones de D. aberiae en cítricos es elevada en primavera y verano, reduciéndose a niveles mucho más bajos en otoño e invierno. Además el insecto completa varias generaciones a lo largo del año, estando dos de ellas muy claramente definidas y siendo las que dan lugar a elevadas poblaciones de la plaga. En cuanto a su distribución, D. aberiae se instaló principalmente en la copa del árbol y se observaron migraciones entre los distintos órganos, mostrando una clara preferencia por el fruto en desarrollo. Entre febrero y septiembre parte de las poblaciones de D. aberiae se encontraron en tronco y suelo, existiendo movimientos de subida y de bajada a la copa en función de la fenología de la planta y las condiciones climáticas. La comparativa entre técnicas de muestreo reveló que las trampas de cartón corrugado proporcionan una medida cuantitativa de la abundancia de D. aberiae en las parcelas. Por su parte, las trampas pegajosas, provistas de hembras de D. aberiae, fueron capaces de detectar los principales vuelos de machos. Por otro lado, D. aberiae causó daños directos al fruto (deformación y/o reducción de tamaño) al alimentarse del ovario de la flor o de los primeros estados de desarrollo de éste. Estos daños son posiblemente debidos a su interferencia con el proceso de división celular. Por último, en Sudáfrica, lugar de origen de la plaga, los mayores niveles poblaciones de D. aberiae se encontraron en verano y la tasa de parasitismo fue máxima en otoño. Entre el complejo de enemigos naturales de D. aberiae encontrados destacaron dos especies, Anagyrus sp. nov. 1 (Hymenoptera: Encyrtidae) y Allotropa sp. nov. (Hymenoptera: Platygastridae). Ambos parasitoides podrían tener un papel importante en un programa de control biológico contra D. aberiae en España. Por ahora, Anagyrus sp. nov. 1 parece el mejor candidato por sus mayores tasas de parasitismo en Sudáfrica. / Delottococcus aberiae (Hemiptera: Pseudococcidae) is an invasive mealybug native to sub-Saharan Africa that was detected causing significant damage to citrus fruits in eastern Spain in 2009. Due to the lack of knowledge about this species, the management of D. aberiae has been carried out by the application of authorized insecticides against mealybugs. However, the latest European Directive (2009/128 / EC) on the sustainable use of pesticides stipulates that chemical treatments in agroecosystems must be reduced, promoting more sustainable management strategies such as the application of biological control methodologies. In addition, when an invasive species arrives for the first time in a territory it is necessary to study its biology, behavior, damage caused and control possibilities. This thesis presents for the first time these studies of biology and behavior of the pest as well as a characterization of the damage produced by D. aberiae. The possibilities of implementing a classical biological control program against this species in citrus in Spain have also been studied. To analyze the biology and behavior of D. aberiae, several citrus orchards infested with the mealybug have been sampled for three years in the Valencian Community (eastern Spain). Samples have been collected periodically and the number of mealybugs, their developmental stage as well as the infested stratum and organ where they were present have being recorded. The period of damage to the fruit was studied in semi-field and field conditions by the artificial infestation with D. aberiae of fruits of different diameter. Finally, the behavior and possibilities of biological control of D. aberiae were studied by sampling several citrus orchards in the native area of the mealybug (South Africa). Results showed that the density of D. aberiae populations in citrus orchards is high in spring and summer, decreasing to lower levels in autumn and winter. In addition, the insect completes several generations throughout the year and two of them are clearly defined and result in high population levels. Regarding its distribution, D. aberiae was mostly installed in the canopy of the tree and migrations were observed between different organs, showing a clear preference for the developing fruit. From February to September some mealybugs were found in the trunk and soil, moving upwards or downwards depending on the phenology of the plant and the climatic conditions. The comparison between sampling techniques revealed that corrugated cardboard band traps provide a quantitative measurement of D. aberiae density in the orchards. On the other hand, sticky traps, baited with D. aberiae females were able to detect the main male flight periods. D. aberiae caused direct damage to the fruit (deformation and/or reduction in size) by feeding on the ovary of the flower or on small fruits in development. These damages are probably due to their interference with the process of cell division. Finally, in South Africa, native area of the pest, the highest density levels of D. aberiae were found in summer and the highest parasitism rates occurred in autumn. Among the complex of D. aberiae natural enemies, the two most abundant species were Anagyrus sp. nov. 1 (Hymenoptera: Encyrtidae) and Allotropa sp. nov. (Hymenoptera: Platygastridae). Both parasitoids could play an important role in a biological control program against D. aberiae in Spain. For now, Anagyrus sp. nov. 1 seems the best candidate because of its higher rates of parasitism in South Africa. / Delottococcus aberiae (Hemiptera: Pseudococcidae) és un pseudocòccid invasor originari de l'Àfrica subsahariana que va ser detectat causant greus danys en cítrics de l'est d'Espanya l'any 2009. A causa del desconeixement existent sobre aquesta espècie, la gestió de D. aberiae s'ha dut a terme mitjançant l'ús de tractaments químics autoritzats contra aquest tipus d'insectes. No obstant això, l'última Directiva Europea (2009/128/EC) sobre l'ús sostenible de productes fitosanitaris estipula que l'aplicació de plaguicides en l'àmbit agrícola ha de reduir-se, promovent estratègies de maneig més sostenibles com és l'aplicació del control biològic de plagues. A més, quan una espècie invasora arriba per primera vegada a un territori és necessari estudiar la seua biologia, comportament, danys causats i possibilitats de control. En aquesta tesi es presenten per primera vegada els estudis de biologia i comportament de la plaga així com una anàlisi dels danys produïts per D. aberiae. També s'han realitzat estudis amb l'objectiu d'implementar l'aplicació d'un programa de control biològic clàssic sobre aquesta espècie en cítrics a Espanya. Per a analitzar la biologia i comportament de D. aberiae s'han mostrejat durant tres anys diverses parcel·les de cítrics amb poblacions de D. aberiae a la Comunitat Valenciana. En aquestes parcel·les s'han recollit mostres i comptabilitzat tots els pseudocòccids presents, el seu estadi de desenvolupament i l'estrat i òrgan de l'arbre on es trobaven. El període de danys al fruit va ser estudiat en semicamp i camp mitjançant la infestació artificial amb D. aberiae de fruits de diferents mides de diàmetre. Finalment es va estudiar el comportament i les possibilitats de control biològic de D. aberiae mostrejant diverses parcel·les de cítrics en la seua zona d'origen (Sud-àfrica). Els resultats van mostrar que l'abundància de les poblacions de D. aberiae en cítrics és elevada a la primavera i estiu, reduint-se a nivells molt més baixos a la tardor i hivern. A més l'insecte completa diverses generacions al llarg de l'any, estant dos d'elles molt clarament definides i sent les que donen lloc a elevades poblacions de la plaga. Quant a la seua distribució, D. aberiae es va instal·lar principalment en la copa de l'arbre i es van observar migracions entre els diferents òrgans, mostrant una clara preferència pel fruit en desenvolupament. Entre febrer i setembre part de les poblacions de D. aberiae es van trobar en tronc i sòl, existint moviments de pujada i de baixada a la copa en funció de la fenología de la planta i les condicions climàtiques. La comparativa entre tècniques de mostreig va revelar que les trampes de cartró corrugat proporcionen una mesura quantitativa de l'abundància de D. aberiae en les parcel·les. Per la seua banda, les trampes apegaloses proveïdes de femelles de D. aberiae van aconseguir detectar els principals vols de mascles. D'altra banda, D. aberiae va causar danys directes al fruit (deformació i/o reducció de mida) en l'alimentar-se de l'ovari de la flor o dels primers estats de desenvolupament d'aquest. Aquest danys són possiblement deguts a la seua interferència amb el procés de divisió cel·lular. Finalment, a Sud-àfrica, lloc d'origen de la plaga, els majors nivells poblacionals de D. aberiae es van trobar a l'estiu i la taxa de parasitisme va ser màxima a la tardor. Entre el complex d'enemics naturals de D. aberiae trobats van destacar dues espècies, Anagyrus sp. nov. 1 (Hymenoptera: Encyrtidae) i Allotropa sp. nov. (Hymenoptera: Platygastridae). Tots dos parasitoides podrien tindre un paper important en un programa de control biològic contra D. aberiae a Espanya. Per ara, Anagyrus sp. nov. 1 sembla el millor candidat per les seues majors taxes de parasitisme a Sud-àfrica. / Martínez Blay, V. (2018). Biology and management, by application of classical biological control, of the invasive mealybug Delotoccoccus aberiae (Hemiptera:Pseudococcidae) in citrus orchards in Spain [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/106363 / TESIS