Orientador: Marineide Rosa Vieira / Resumo: A Helicoverpa armigera é uma praga importante no Brasil desde sua introdução em 2013. Pode provocar danos na cultura da soja desde a fase de emergência das plantas até o enchimento de grãos nas vagens. O objetivo deste trabalho foi quantificar os danos causados pelas lagartas de H. armigera no estádio vegetativo e reprodutivo da cultura da soja, em casa de vegetação e campo e determinar o nível de controle para praga no período reprodutivo da cultura. Foram conduzidos experimentos na safra 2014/2015 e 2015/2016. Safra 2014/2015: Foi realizada a quantificação dos danos no período vegetativo e reprodutivo da cultura da soja. Os experimentos foram conduzidos em casa de vegetação, o delineamento adotado foi de blocos ao acaso, com cinco tratamentos e quatro repetições. Cada parcela constou de um vaso retangular, com aproximadamente 50 cm de comprimento e volume aproximado de 13L de solo contendo sete plantas dispostas em linha. Os tratamentos constaram da infestação de uma, duas, três, cinco e nenhuma lagarta em 0,5m de linha da cultura. No período vegetativo, as plantas foram infestadas quando as lagartas atingiram o segundo instar e quando as plantas se encontravam no estádio de desenvolvimento V4. No período reprodutivo as plantas foram infestadas quando as lagartas atingiram o segundo ínstar e as plantas encontravam-se no estádio R4 de desenvolvimento. Para ambos os experimentos as avaliações foram realizadas a cada dois dias até o término do ciclo larva da praga. Ao término ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Helicoverpa armigera has been important pest in Brazil since its introduction in 2013. The H. armigera species can cause damage to the soybean crop from the emergence of the plants at the filling of grain in the pods. The objective of this study was to quantify the damage caused by H. armigera caterpillars in the vegetative and reproductive phase of soybean crop in a greenhouse and field and to establish the level of control for the pest in the reproductive phase of the crop. Experiments were conducted in the 2014/2015 and 2015/2016 harvests. Harvest 2014/2015: Was quantification of the damages in the vegetative and reproductive period of the soybean crop. The experiments were conducted in greenhouse, the experimental design was randomized blocks with five treatments and four replications. Each plot consisted of a rectangular vase, approximately 50 cm long and with an approximate volume of 13L of soil containing seven plants in a row. Treatments consisted of infestation of one, two, three, five and no caterpillar on a half meter line of crop planted. In the vegetative period, the plants were infested with caterpillars of second instar and when the plants were in the V4 development stage. In the reproductive period the plants were infested with caterpillars of second instar and the plants were in the developmental stage R4. For both experiments the evaluations were carried every two days until the end of the pest larval cycle. At the end of the crop cycle, the yield was evalua... (Complete abstract click electronic access below) / Mestre

Master of Science / Department of Grain Science and Industry / Bhadriraju Subramanyam / A synthetic zeolite (Odor-Z-Way, sodium aluminum silicate) used for odor adsorption was tested for its ability to control adults of stored-grain insects on wheat and on concrete petri dishes used to simulate floors of empty bins. Insect species tested included unsexed adults of the lesser grain borer, Rhyzopertha dominica (F.); rice weevil, Sitophilus oryzae (L.); maize weevil, Sitophilus zeamais (Motschuslky); red flour beetle, Tribolium castaneum (Herbst), and sawtoothed grain beetle, Oryzaephilus surinamensis (L.). Two formulations were evaluated under laboratory conditions (28±1⁰C and 65±1% r.h.): coarse zeolite (with 90% of particles having a mean diameter at or below 155 µm) and fine zeolite (with 90% of particles having a mean diameter at or below 47.0 µm). On concrete, arenas in 9-cm diameter Petri dishes were sprinkled with the synthetic zeolite to provide deposits of 0 (control), 5 and 10 g/m[superscript]2. Mortality was assessed at times ranging from 10 minutes to 24 hours followed by 48 hours recovery on wheat. Mortality in adults of the five species increased as the rate of application and the duration of exposure increased. Concrete Petri dishes sprinkled with the fine zeolite yielded percent mortality greater or equal to that observed with the coarse zeolite- sprinkled Petri dishes. Bioassays on wheat were conducted using two dosage rates: 0.1 to 3.0 g/kg for R. dominica and 0.05 to 1.0 g/kg for the other insect species. Mortality was assessed 7 days post- infestation. A concentration of 0.75 g/kg of fine or coarse zeolite achieved 100% mortality in adults of S. zeamais, T. castaneum, and O. surinamensis. All adults of S. oryzae were killed using 0.50 g/kg of coarse or fine zeolite. Adults of R. dominica were the least susceptible: 2.50 g/kg of fine zeolite and 3.0 g/kg of coarse zeolite were required for 100% mortality. Mortality generally increased with the concentration of zeolite applied on wheat. Efficacy was not related to particle size. This is the first study showing the efficacy of a synthetic zeolite against adults of five species of stored-product insects on concrete and wheat. Synthetic zeolites can be a suitable alternative to currently used pesticides for treatment of empty bin floors and stored wheat for insect control.

Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Increasing pressure on food production and the concern over maintenance of biodiversity and ecosystem services is creating an urgent need to future-proof food production, while maintaining the natural environment for future generations. Within the Cape Floristic Region (CFR) biodiversity hotspot in the Western Cape of South Africa, deciduous fruit is widely grown, contributing significantly to the local economy. To ensure access is maintained to important export markets, this study reviews the current available pest control options with focus on techniques able to preserve the biodiversity of the CFR, while simultaneously providing effective control over arthropod pests in pome fruit. A scenario planning technique is then used to depict potential future scenarios and the options we have in dealing with them. Emphasis here is placed on economically important arthropod species, particularly Mediterranean fruit fly Ceratitis capitata (Wiedemann) and codling moth Cydia pomonella (L.). Biological control (biocontrol) is discussed in detail, covering predators, parasitoids and pathogens. Biocontrol is an important, sustainable pest control measure. However, certain risks associated with releasing living organisms into the environment must not be ignored. Monitoring of release programmes is essential. The sterile insect technique (SIT) offers a species-specific approach to controlling pests. However, the technique is research and management intensive. Globally SIT has shown great success, but lack of financial support has limited SIT uptake locally. SIT has shown increased effectiveness as an integrated technique, particularly with parasitoid release and pheromone-based mating disruption. The management of orchards as agroecosystems shows that preservation of natural vegetation and beneficial plant species increases crop resilience, encourages conservation biological control and maintains crop health. The importance of area-wide control is discussed under each section, as a favourable strategy which deals with entire pest populations rather than isolated farm-by-farm approaches. Other techniques covered include pheromone-based mating disruption, attract-and-kill and physical barriers such as sticky tree-bands, which all show integration potential with biologically-based techniques while minimising insecticide application. The usefulness of insecticides as a curative approach is recognised, and ways of preserving insecticide life-spans by limiting insecticide resistance are discussed. Social, economic, political, environmental and technological driving forces are used to develop four realistic future scenarios for pome fruit production in the CFR. The scenarios are based on the extremes of two key uncertainties: development of resistance to chemical insecticides, and changes in legislation regulating insecticide usage. The options we face in dealing with each potential scenario, with the suite of arthropod pest control techniques currently developed, is discussed. It is hypothesised that a best-case scenario, in which environmentally-friendly techniques which support healthy, productive agroecosystems, can be reached. We should carefully assess our options, and begin to shift pest control from a predominantly chemical basis to one in which habitat management and biocontrol form the basis of control, with techniques such as SIT, mating disruption and physical barriers assisting in creating holistic arthropod pest control systems. In light of the uncertainty that the future holds, a scenario planning exercise such as this, can assist in decision making today that will best prepare us to deal with future threats such as climate change and new pest invasions. / AFRIKAANSE OPSOMMING: Toenemende druk op voedselproduksie en kommer oor die handhawing van biodiversiteit en ekosisteemdienste lei tot „n dringende behoefte om voedselproduksie toekoms-bestand te maak, asook om tegelykertyd die natuurlike omgewing vir toekomstige generasies te bewaar. Binne die Kaap Floristiese Streek (KFS) „biodiversiteitskern‟ in die Wes-Kaap van Suid-Afrika word sagte vrugte algemeen verbou en lewer „n aansienlike bydrae tot die plaaslike ekonomie. Om toegang tot belangrike uitvoermarkte te verseker ondersoek hierdie studie die plaagbeheer opsies tans beskikbaar, met die fokus op tegnieke wat die biodiversiteit van die KFS kan bewaar en tegelykertyd effektiewe beheer oor geleedpotige plae van kernvrugte kan verskaf. „n Scenario-beplannings-tegniek word dan gebruik om moontlike toekomstige scenario‟s en die opsies tot ons beskikking om hulle te hanteer, uit te beeld. Klem word hier geplaas op geleedpotige spesies van ekonomiese belang, veral die Mediterreense vrugtevlieg, Ceratitis capitata (Wiedemann) en die kodlingmot Cydia pomonella (L.). Biologiese-beheer (biobeheer) word in diepte bespreek, en dek predatore, parasiete en patogene. Biobeheer is „n belangrike, volhoubare plaagbeheer-middel; alhoewel sekere risiko‟s verbonde met die vrystelling van lewende organismes in die omgewing nie verontagsaam moet word nie. Dit is noodsaaklik dat vrystellingsprogramme gemoniteer word. Die steriele-insek-tegniek (SIT) bied „n spesies-spesifieke benadering tot die beheer van plae, alhoewel dit navorsings- en bestuursintensief is. SIT het wêreldwyd al groot suksesbehaal, maar „n tekort aan finansiële ondersteuning het die plaaslike toepassing van SIT beperk. SIT het verhoogde effektiwiteit as „n geïntegreerde tegniek vertoon, veral met die verlies van parasiete en feromoon gebaseerde parings-ontwrigting. Die bestuur van boorde as agro-ekosisteme wys dat die bewaring van natuurlike plantegroei en voordelige plant spesies oes-herstelvermoë verhoog, bewaring-biologiese-beheer aanmoedig en oes-welstand handhaaf. Die belang van streekswye beheer word bespreek onder elke afdeling as „n gunstige strategie wat te doen het met algehele plaagbevolkings, eerder as afsonderlike plaas-tot-plaas benaderings. Ander tegnieke wat gedek word sluit in feromoon gebaseerde parings-ontwrigting, lok-en-doodmaak en fisiese versperrings soos taai boom-bande, wat alles integrasie-potensiaal wys met biologies gebaseerde tegnieke en tegelykertyd insekdoder aanwending verminder. Die nuttigheid van insekdoders as „n herstel benadering word erken en maniere om die leffektiwiteit van insekdoders te behou deur insekdoder-weerstand te beperk, word bespreek. Sosiaal-, ekonomies-, polities-, omgewings- en tegnologies-gedrewe kragte word gebruik om vier realistiese toekomstige scenario‟s vir kernvrug-produksie in die KFS te ontwikkel. Die scenario‟s is baseer op die ekstreme van twee belangrike onsekerhede: ontwikkeling van weerstand teen chemiese insekdoders, en veranderinge in wetgewing wat die gebruik van insekdoders reguleer. Die opsies wat ons in die gesig staar om elke potensiële scenario te hanteer met die verskeidenheid van geleedpotige plaagbeheer-tegnieke tans ontwikkel is, word bespreek. Dit word veronderstel dat „n beste scenario, waar omgewings-vriendelike tegnieke wat gesonde, produktiewe agro-ekosisteme onderhou, bereik kan word. Ons moet ons opsies versigtig assesseer, en begin om plaagbeheer vanaf „n oorwegend chemiese basis te skuif na een waar habitat-bestuur en biobeheer die basis van beheer vorm, en waar tegnieke soos SIT, parings-ontwrigting en fisiese versperrings help om holistiese geleedpotige-plaagbeheer sisteme te vorm. In die lig van die onsekerheid wat die toekoms inhou, kan „n scenario-beplannings oefening soos hierdie besluitneming vandag aanhelp wat ons die beste sal voorberei vir die hantering van toekomstige bedreigings soos klimaats-verandering en nuwe en vreemde plaag-indringing.

Natural enemies provide critical population regulation of many pest species, though their effects are not commonly incorporated into agricultural management decisions. Conservation biological control is an important tool that can be implemented to minimize pest damage, but applying it requires appropriate understanding of pest and natural enemy relationships. Through experimental cotton field trials, I identified predator: prey ratios based on key arthropod predators as action thresholds of the whitefly pest Bemisia tabaci MEAM1 (Dinsdale et al. 2010; equivalent to Bemisia argentifolii Bellows et al. 1994 [Hemiptera: Aleyrodidae]), validated their efficacy, and promoted them to cotton pest managers. This dissertation begins with a multi-year field trial where whitefly and natural enemy populations were manipulated with a series of insecticidal treatments to identify key arthropod predators. The critical abundance of four key predators necessary to suppress whiteflies was estimated through predator: prey ratios. These ratios were refined for commercial pest management and developed to conform to the current whitefly IPM framework as a simple to use management-decision tool that would be readily adopted and used by pest managers. Predator: prey ratios were then validated in 1) a second field trial, 2) commercial fields in Arizona and northern Mexico and 3) historical field trials conducted from 1997-2010, where whitefly management decisions made with the standard threshold and ratios, were compared with the standard threshold alone. I found no difference in management outcomes when decisions were made with the standard threshold alone, or with predator: prey ratios in the field trial, but analysis of potential decisions on commercial farms and with historical trial data indicated that the majority of sprays could be delayed if control decisions incorporated ratio-based thresholds. Finally, an outreach program was developed and deployed to present ratios as decision-making tools for cotton pest managers that reduce uncertainty in control decisions and optimize spray outcomes. Pest managers indicated positive changes in knowledge and a gradual adoption of ratios for decision-making. The implementation of whitefly control decisions that incorporate predator: prey ratios may reduce pest managers' uncertainty in decision-making, as well as insecticide use and management costs.

Despite substantial consumer demand and willingness to pay premium prices for organically grown fruit, apple growers in Vermont and other New England states have been slow to adopt certified organic practices. Barriers cited in the past to increased adoption of organic apple production in the region include susceptibility of traditionally grown cultivars to apple scab, lack of effective insect pest management materials, and few available effective options for fruit thinning. Recent changes in apple cultivar plantings in the region, introduction of new insect pest management materials, and advances in crop thinning justified an evaluation of organic apple production systems containing cultivars identified as important to the future of the apple industry. In 2006, two apple orchards were established at the University of Vermont Horticulture Research and Education Center in South Burlington, VT to comprehensively evaluate the five commercially-important apple cultivars of `Ginger Gold', `Honeycrisp', `Liberty', `Macoun', and `Zestar!' over eight growing seasons in two organically-managed orchard production systems, including a newly-planted high-density orchard (Orchard 1) and in an existing, medium-density orchard which was top-grafted to the new cultivars (Orchard 2). Parameters for tree growth and survival, crop yield, disease and arthropod pest incidence on foliage and fruit, and long-term economic return, including a twenty-year projection of net present value (NPV) of each cultivar in the two systems were evaluated in this study. `Ginger Gold', despite high incidence of some diseases on foliage and fruit, performed the best in both orchard systems overall. The cultivar was among the cultivars with the highest measurements of tree growth. `Ginger Gold', along with `Honeycrisp', had the highest cumulative net crop yield per tree in Orchard 1 and the highest in Orchard 2. Notably, apple scab on `Honeycrisp' foliage and fruit and `Zestar!' fruit in both orchards was at a level that was not significantly different from `Liberty', a scab-resistant cultivar on which no scab was observed. However, `Honeycrisp' had the highest incidence of fruit rots in both orchards, but it was not significantly different than `Zestar!' in Orchard 1. Management of lepidopteran pests of fruit was a major challenge on all cultivars over the years of the study. For most of the tree growth parameters and cumulative net crop yield, `Liberty' was among the lowest group of cultivars in both orchards. Cumulative net crop yield of both `Macoun' and `Zestar!' were also among the lowest in both orchards with the top-grafted `Macoun' and `Zestar!' trees having significant tree death compared to the other cultivars in Orchard 2. Harvested fruit were graded to commercial standards and cumulative gross and net income calculated from grade distribution, crop yield, and fruit price data. In Orchard 1, `Ginger Gold' and `Liberty' had greater cumulative gross income per hectare from 2006-2013, in excess of US$40,000, compared to `Liberty'. However, after management costs were deducted, all cultivars in Orchard 1 had negative cumulative net income of $-77,892 or less. In Orchard 2, all cultivars had positive cumulative net income for 2006-2013, and `Ginger Gold' had the highest at $109,717/ha. The twenty-year projected NPV was negative for all cultivars in Orchard 1, but in Orchard 2, all cultivars had positive NPV with `Ginger Gold' having the highest among the cultivars.

The demand for locally sourced hops from Northeastern microbreweries began the recent resurgence in local hop production. The farming community has increased acreage and improved the quality of hops grown and processed in the Northeast region over the past five years. There was a sharp increase in the number of Northeast hop producers from six in 2009 to over 175 in 2014. Hop growers in the Northeast are new to the crop and have limited experience with pest identification and management. This dissertation encompasses three research projects that were conducted over the 2012-2014 growing seasons. These projects were the first critical steps taken to develop arthropod integrated pest management (IPM) tactics for Northeastern hop growers. First, the arthropod community in seven Vermont hop yards was evaluated. The objectives of Chapter 2 are to 1) present current hop pest biology and management strategies, 2) report the phenology of arthropod pests observed over three growing seasons, 3) report abundance and peak date for each pest, and 4) document natural enemy abundance in Vermont hop yards. The survey indicates that in cool, wet seasons hop aphid (Phorodon humuli Schrank) is expected to be a pest of concern. Two-spotted spider mite (Tetranychus urticae Koch) is expected to be a pest of concern in hot, dry conditions. Potato leafhopper (Empoasca fabae Harris) is an unpredictable pest of special concern for first year hop plants. When hop aphid or potato leafhopper are sprayed for with broad-spectrum insecticide, two-spotted spider mite secondary outbreak can be expected. Second, the abundance of major arthropod pests and their natural enemy groups were evaluated under drive row flowering cover crop treatments. The objectives of this study were to 1) measure the effect of cover crops on natural enemy group abundance, 2) measure the effect of cover crops on the three major Northeastern hop pests, and 3) measure the effect of cover crop presence on hop yield and quality. Natural enemy groups and pests were positively correlated yet cover crop treatments had no significant effect on natural enemy abundance. Red clover cover crop treatments served as a trap crop for potato leafhopper. No significant difference in hop yield or quality was observed between flowering cover crop treatments. Finally, potato leafhopper is a documented but understudied regional pest of hops. The objectives of this study were to 1) measure the physiological response of eight hop cultivars to adult potato leafhopper feeding and 2) measure hop leaf recovery from potato leafhopper injury. Gas exchange (net photosynthesis and transpiration) and chlorophyll content were measured to quantify injury by adult potato leafhopper to first year hop leaves in field and greenhouse studies. Cultivars did not vary significantly in their physiological response to potato leafhopper feeding. Injury significantly reduced gas exchange measures in the field (P < 0.05) and greenhouse (P < 0.05) and when leafhoppers were removed, gas exchange was restored.

Doctor of Philosophy / Department of Entomology / Thomas W. Phillips / Robert "Jeff" J. Whitworth / Dry-cured ham is protected from infestations of Tyrophagus putrescentiae (Schrank) (Sarcoptiformes: Acaridae) with the fumigant methyl bromide. Developing feasible alternatives to methyl bromide is necessary due to the phase out of methyl bromide. The effectiveness of food-safe compounds for preventing infestations of T. putrescentiae on dry-cured hams was evaluated by dipping ham pieces in solutions of various food additives. Propylene glycol (1, 2-propanediol), lard, ethoxyquin and butylated hydroxytoluene prevented or significantly reduced mite population growth. A combination of carrageenan + propylene glycol alginate + 40% propylene glycol was effective in reducing mite numbers on treated whole-aged hams compared with untreated hams. Dose/response tests with twelve registered residual insecticides were conducted to assess contact toxicity to T. putrescentiae. Three of these insecticides were evaluated for persistence over a 2-month period on different surfaces. Commercial formulations of deltamethrin plus chlorpyrifos-methyl, chlorfenapyr, and malathion showed promising results for contact toxicity against T. putriscentiae. Chlorfenapyr applied to metal, concrete, and wood resulted in 100% mortality of treated ham mites for up to 8 weeks. The effect of high and low temperatures on mortality of T. putrescentiae was studied in the laboratory. Groups of 10 eggs and groups of a mixture of 40 adults and nymphs were separately exposed to several high and low temperatures, ranging from +35 to 45°C and from −20 to +5°C, for several time periods. Eggs were found to be more tolerant to both high and low temperatures compared with adults and nymphs. Results showed that high temperatures from 40-45°C killed all T. putrescentiae eggs, adults, and nymphs within 4-1 d, while −10°C or lower killed all the same stages in less than 1 d. Combinations of the fumigant sulfuryl fluoride (SF) applied under high temperatures ranging from 25-40ºC, were studied to determine the highest temperature, shortest exposure time, and the lowest value of a concentration-by-time product (CTP) of SF against T. putrescentiae. Results showed that complete control of all life stages of T. putrescentiae was achieved at 40ºC with SF. More than one day of exposure was required to kill adults and nymphs and eggs at 40ºC at a CTP close to the EPA labeled rate of 1500 gh.m⁻³. Results indicated that adults and nymphs were more susceptible to SF compared to eggs. This study focused on investigating different control methods for T. putrescentiae in dry-cured ham facilities and most of examined techniques are preventive, although some of them can be applied as remedial methods after mite infestations are noticed.

Rodent commensal species produce great damage in agriculture and urban areas. As invasive species they can endanger local species and are carriers and vectors of several important zoonoses. Control methods rely mainly on the use of warfarins, which can be inadvertently be taken up by untargeted species. Warfarins have also lost their efficacy in rodents due to the development of genetic resistance. In addition, these methods are considered inhumane as they cause a slow and painful death due to haemorrhages. Olfaction is a main source for environmental risk assessment by rodents, and it can be used to modify their use of space. My aim in this thesis was to identify behavioural reactions of the house mouse (Mus musculus), using laboratory strains as models of wild animals, to ecologically meaningful chemical messages, including predator and plant chemical olfactory cues. My results showed that mice avoided complex ferret olfactory cues and ethanol which is a ubiquitous chemical related to fruit rotting and ripening. The feline protein Fel d 1, which belongs to the secretoglobin family and is a major cat allergen in humans, did not elicit significant avoidance or alter foraging behaviour in mice. However, Trimethylthiazoline purified from fox faeces, elicited clear avoidance behaviour and stress responses. I carried out a bibliographic review to evaluate and discuss rodent pest control methods from an ethical standpoint. This literature showed that many of the current methods of pest control are considered inhumane, and do not tally with current society concerns and welfare standards in other domains such as farms or laboratory animals. These results raise new research questions to identify ferret and plant chemical compounds that can induce rodent avoidance, and to carry out next stage of research with wild animals both under laboratory and field conditions.

A espécie Helicoverpa armigera Hübner, 1809 (Lepidoptera: Noctuidae) vem atacando diversas culturas de importância econômica, e os prejuízos estimados nas safras de 2012/2013 no Brasil, foram de aproximadamente, 2 bilhões de reais. Com o uso intensivo de inseticidas sintéticos para controlar H. armigera, esta praga mostrou alta resistência em resposta a esses inseticidas. Visando diminuir o uso indiscriminado de inseticidas, uma alternativa à utilização de inseticidas sintéticos para o controle de pragas é o uso de parasitoides do gênero Trichogramma. Portanto, o objetivo do presente trabalho foi determinar os locais de oviposição de H. armigera, otimização da criação de H. armigera em laboratório, selecionar a linhagem mais adequada de Trichogramma pretiosum Riley, 1879 (Hymenoptera: Trichogrammatidae) para o controle de H. armigera na cultura de soja, determinação do número de parasitoides a ser liberado por ovo da praga para se atingir o máximo de parasitismo, e capacidade de parasitismo de T. pretiosum em ovos de H. armigera e de Chrysodeixis includens (Walker, 1857) (Lepidoptera: Noctuidae). A preferência de oviposição de H. armigera em plantas de soja foi pela parte superior das plantas e em folhas, em todos os estádios fenológicos observados. Os resultados, obtidos por meio dos experimentos para ajustar a criação de H. armigera em laboratório, apontaram que a cópula de casais emergidos no mesmo dia levaram a um aumento na produção de ovos por dia. Por meio da seleção de espécies/linhagens de Trichogramma e Trichogrammatoidea constatou-se que T. pretiosum, linhagem coletada em Rio Verde, GO (RV) e Sorriso, MT (SO) apresentaram melhor desempenho biológico. Em condições de semi-campo, determinou-se que o maior parasitismo foi obtido com uma proporção de 3,2 parasitoides por ovo da praga. Em um processo competitivo entre 2 espécies de lepidópteros em soja, T. pretiosum tem preferência por H. armigera em relação a C. includens. / The cotton bollworm Helicoverpa armigera Hübner, 1809 (Lepidoptera: Noctuidae) attacks several economically important crop plants. In Brazil, the estimated damage to the 2012-2013 harvest was about 2 billion reals (currently equivalent to 600 million US dollars). In response to the intensive use of synthetic insecticides to control H. armigera, the pest developed a high degree of resistance. In order to reduce the indiscriminate use of insecticides, one alternative is to use parasitoid wasps of the genus Trichogramma. The present study had the objective of determining the oviposition sites of H. armigera, optimizing its rearing in the laboratory, selecting the most appropriate strain of Trichogramma pretiosum Riley, 1879 (Hymenoptera: Trichogrammatidae) to control H. armigera on a soybean crop, determining the number of parasitoids to be released per egg of the pest in order to attain the maximum parasitism, and the capacity of T. pretiosum to parasitize eggs of H. armigera and Chrysodeixis includens (Walker, 1857) (Lepidoptera: Noctuidae). On soybean plants, H. armigera prefers to oviposit on leaves on the superior part of the plants, in all the phenological stages observed. The results of the experiments to adjust the procedures for rearing H. armigera in the laboratory indicated that copulation of couples that had emerged on the same day led to an increase in daily egg production. Selection of species and strains of Trichogramma and Trichogrammatoidea established that T. pretiosum strains from specimens collected in Rio Verde, Goiás (RV) and Sorriso, Mato Grosso (SO) showed better biological performance than others. In semi-field conditions, the highest parasitism was obtained with a proportion of 3.2 parasitoids per pest egg. In a trial comparing its preference for two species of lepidopterans on soybean, T. pretiosum preferred H. armigera to C. includens.

Insect-symbiont interactions have many bioecological consequences to the host. Their relationships expand through a complex network that includes other microorganisms, interactions with the environment and other trophic levels. An extensive literature has been produced on bacterial symbionts and aphids, especially for polyphagous aphids from North America and Europe, such as Acyrthosiphon pisum (Harris). They indicated symbionts influence host nutrition, heat tolerance, defense against natural enemies, virus transmission, host plant exploitation, among others. However, the outcome from host-symbiont interactions is context-dependent, with the expressed phenotype depending on intra and interspecific variations, symbiont strain, and biotic/abiotic stimuli. We explored the interaction between aphids and associated symbionts, aiming to contribute to this field by exploring new aphid systems, and focused on Aphis (Toxoptera) citricidus (Kirkaldy) and associated microbiota. We investigated the influence of the feeding habits on symbiont diversity in an oligophaogus, A. citricida, as compared to a polyphagous species, Aphis (Toxoptera) aurantii Boyer de Fonscolombe. We employed several approaches (biological, metagenomics, genomic, and proteomic) to investigate i) the impact of host plants on fitness traits and primary symbiont abundance in the oligophagous and polyphagous species, ii) differences in the draft genome of the primary aphid symbiont between A. citricidus and A. aurantii, iii) the influence of host plant in secondary symbiont distribution in A. citricidus, iv) secondary symbiont richness and abundance in both aphids, and investigate the effects of Spiroplasma infections v) in the fitness traits, vi) transcriptome and ii) proteome of A. citricidus when reared on two host plants (sweet orange and orange jasmine). Our data indicated that sweet orange is a better host plant than orange jasmine for both aphids, and that A. citricidus was more negatively affected by lower-quality host than A. aurantii. A. citricidus and A. aurantii had different strategies regarding Buchnera growth and the use of food in different stages of development. We observed differences in the draft genome of Buchnera associated to A. citricidus and A. aurantii. Host plant affected secondary symbiont abundance, but Spiroplasma was the most abundant symbiont in both aphids. Spiroplasma had neutral effects on A. citricidus biology, but affected host transcriptome and proteome. The host plant affected gene expression of A. citricidus, but the effect was dependent on Spiroplasma infection. Transcriptome analysis indicated Spiroplasma down-regulated aphid immune response genes on sweet orange, while regulating an entire different set of genes on orange jasmine, mainly chaperonins. Gene transcription of A. citricidus was strongly influenced by the host plant. But while a large number of transcripts were up-regulated in uninfected aphids in sweet orange as compared to orange jasmine, the same set of genes had an opposite pattern of expression in Spiroplasma-infected aphids. Comparative proteomic analysis of Spiroplasma-infected and uninfected aphids on sweet orange and orange jasmine demonstrated regulation of a larger number proteins on orange jasmine than on sweet orange. Spiroplasma down-regulated the immune response of aphids and up-regulated proteins related to nutritional processes when developing on a low-quality host plant, orange jasmine, while no such trend was observed on sweet orange. / A associação insetos - bactérias simbiontes resulta em várias implicações bioecológicas para o hospedeiro e se estende em uma rede de interações que inclue outros microrganismos, o ambiente e outros níveis tróficos. A interação bactérias simbiontes e pulgões tem sido amplamente estudada, especialmente em espécies polífagas do hemisfério norte, tal como o pulgão modelo Acyrthosiphon pisum (Harris). Essas pesquisas indicam que simbiontes influenciam vários aspectos ecológicos do hospedeiro, tais como: nutrição, resistência ao estresse térmico e inimigos naturais, capacidade de transmissão de fitovírus, uso de plantas hospedeiras, entre outros. Entretanto, o resultado da interação simbionte-pulgão é contexto dependente, no qual o fenótipo depende da variabilidade intra- e interespecífica, da linhagem do simbionte e de diversos fatores bióticos e abióticos. Assim, este trabalho aborda as interações do pulgão Aphis (Toxoptera) citricidus (Kirkaldy) e seus simbiontes, com o objetivo de contribuir com um sistema ecológico diferente. Foi investigada a influência da estratégia alimentar na diversidade da microbiota, comparando-se uma espécie oligófaga, A. citricidus, a outra polífaga, Aphis (Toxoptera) aurantii Boyer de Fonscolombe. Foram utilizadas diversas abordagens experimentais (biológica, metagenômica, genômica, transcritômica e proteômica) para atingir os objetivos de i) investigar o impacto das plantas hospedeiras na aptidão biológica de A. citricidus e A. aurantii e sua consequência ao simbionte primário, ii) explorar as diferenças no genoma do simbionte primário de A. citricidus e A. aurantii, iii) investigar a influência da planta hospedeira na distribuição de simbiontes secundários em A. citricidus, iv) pesquisar a riqueza e abundância de simbiontes secundários nas duas espécies de pulgão e indagar sobre a influência de Spiroplasma v) na aptidão biológica, vi) no transcritoma e vii) na proteômica de A. citricidus em duas plantas hospedeiras (laranja vs. murta). Os resultados indicaram ser laranja o melhor hospedeiro para ambos pulgões, sendo A. citricidus mais sensível à planta hospedeira que A. aurantii. As duas espécies de pulgão utilizam estratégias distintas para controlar o crescimento de Buchnera, assim como a utilização do alimento influenciou diferentemente cada fase do desenvolvimento dos pulgões estudados. A planta hospedeira também influenciou a abundância de simbiontes secundários; porém, Spiroplasma foi o simbionte secundário mais abundante em ambas espécies. Spiroplasma não afetou a biologia de A. citricidus, mas causou alterações no transcritoma e no proteoma do hospedeiro. A planta hospedeira também exerceu forte regulação na transcrição gênica de A. citricidus, mas esse efeito foi dependente da infecção do pulgão por Spiroplasma. Análises de transcritoma em pulgões infectados indicaram a regulação de transcritos relacionados à resposta imunológica quando em laranja, mas de chaperoninas em murta. A regulação gênica de A. citricidus foi fortemente influenciada pela planta hospedeira, mas enquanto insetos livres de Spiroplasma apresentaram superexpressão gênica em laranja quando comparada a murta, pulgões infectados com esse simbionte apresentaram padrão de expressão oposto para o mesmo conjunto de transcritos. Análises comparativas do proteoma de pulgões infectados ou não por Spiroplasma nas plantas hospedeiras estudadas indicaram diminuição dos mecanismos de defesa em favor de um aumento de proteínas ligadas à nutrição em insetos infectados quando se alimentando em murta.