Orientador: Sérgio de Freitas / Banca: Arlindo Leal Boiça Júnior / Banca: Márcio da Silva Araújo / Resumo: Este estudo teve como objetivo verificar o potencial de predação de E. flavens através da liberação de ovos embrionados e larvas de primeiro ínstar de C. externa em plantas de amendoim cultivadas em casa-de-vegetação. O delineamento experimental utilizado foi o inteiramente casualizado com três tratamentos (plantas que não receberam liberação, plantas que receberam liberação de ovos embrionados e plantas que receberam liberação de larvas de primeiro ínstar) e 15 repetições no primeiro experimento e 20 no segundo. Foram realizadas amostragens antes da liberação e com 4, 9 e 15 dias após. No primeiro experimento e em relação às diferentes amostragens, as plantas que não receberam liberação o número médio de tripes não variou significativamente. As plantas que receberam liberação de ovos e larvas apresentaram aumento significativo do número médio de tripes aos quatro dias. Aos nove dias o número médio de tripes reduziu-se significativamente nas plantas que receberam liberação de ovos e aos 15 dias nas plantas que receberam liberação de larvas. No segundo experimento e em relação às diferentes amostragens, o número médio de tripes nas plantas que não receberam liberação não variou significativamente, como ocorrido no primeiro experimento. As plantas que receberam liberação de ovos apresentaram redução significativa no número médio de tripes aos quatro dias após a liberação. O mesmo ocorreu com as plantas que receberam liberação de larvas. Foi observado no segundo experimento, através da fórmula de Abbott, eficiência de redução da população de tripes de 71 e 74%, quando foram liberados ovos e larvas, respectivamente. Dessa maneira foi possível verificar que C. externa possui potencial de predação sobre o tripes do amendoim E. flavens / Abstract: This study was carried out in order to verify the potential of predation of E. flavens through the release of fertilized eggs and first instar larvae of C. externa peanut plants grown in a greenhouse. The experimental design was completely randomized design with three treatments (plants that did not receive release, plants that received release embryonated eggs and plants that received release of the first larval instar) and 15 repetitions in the first experiment and 20 in the second. Samplings were made before the release and with 4, 9 and 15 days. In the first experiment and for the different samples, plants that were not release the average number of thrips did not vary significantly. The plants that received the release of eggs and larvae showed significant increase in the average number of thrips to four days. At nine days the average number of thrips decreased significantly in plants that received release of eggs and 15 days in plants that received release of larvae. In the second experiment and for the different samples, the average number of thrips on plants that did not receive release did not vary significantly, as occurred in the first experiment. The plants that received the release of eggs showed a significant reduction in the average number of thrips to four days after release. The same occurred with the plants that received release of larvae. Was observed in the second experiment, using the formula of Abbott, efficiency of reducing the population of thrips on 71 and 74%, when they were released eggs and larvae, respectively. Thus we observed that C. has the potential external predation on thrips in peanut E. flavens / Mestre

A família Chrysopidae é a mais diversa dentro da ordem Neuroptera e os crisopídeos são considerados promissores agentes de controle biológico, pois, alimentam-se de uma ampla variedade de pequenos insetos-pragas. O objetivo do presente trabalho foi comparar os aspectos biológicos e reprodutivos, determinar as exigências térmicas e estabelecer o zoneamento climático de quatro espécies de crisopídeos, Chysoperla externa (Hagen), Ceraeochrysa cubana (Hagen), Ceraeochrysa cincta (Schneider) e Ceraeochrysa paraguaria (Navás) para o estado de São Paulo. Os resultados demostraram que, as quatro espécies de crisopídeos conseguiram completar seu período ovo-adulto na faixa térmica de 18 a 32 °C, sendo as melhores viabilidades obtidas entre 20 e 28 °C. Foi observado que a espécie Ch. externa teve um desenvolvimento mais rápido do que as demais espécies em cada estágio de desenvolvimento e período ovo-adulto. Na tabela de vida de fertilidade, o crescimento populacional foi favorecido na faixa térmica de 22 a 28 °C para Ce. cincta, de 22 a 25 °C para Ce. paraguaria, de 25 a 28 °C para Ch. externa e para Ce. cubana na temperatura de 28 °C. As exigências térmicas das espécies indicaram que a temperatura base (Tb) foi de 10,5; 12,95; 11,99; 11,77 °C e a constante térmica de 443,81; 362,7; 399,68 e 314,95 GD para as espécies Ce. cincta, Ce. cubana, Ce. paraguaria e Ch. externa, respectivamente. Mediante as exigências térmicas e o uso de ferramentas computacionais como o Sistema de Informação Geográfica (SIG) foi possível representar de forma espacial o desenvolvimento das quatro espécies de crisopídeos. Devido ao período mais curto de vida, Ch. externa conseguiu completar 14 gerações/ano e as demais espécies de 10 a 11 gerações/ano nas regiões mais quentes do estado de São Paulo. Nas regiões mais frias, o número de gerações anuais estimado para cada espécie foi menor. Além disso, foi observado que entre as espécies estudadas, Ch. externa pode ser indicada para regiões com temperaturas amenas a quentes, Ce. cincta para climas amenos a frios, Ce. paraguaria para regiões com temperaturas amenas e Ce. cubana para regiões com temperaturas quentes . Os dados obtidos neste estudo poderão ser utilizados em criação massal das espécies, auxiliar na previsão de ocorrência dos predadores no campo e escolher quais das espécies se adaptam melhor a determinados climas no ambiente visando o uso destes predadores em programas de Manejo Integrado de Pragas. / The Chrysopidae family is the most diverse in the order Neuroptera and lacewings are considered promising biological control agents, because they feed on a wide variety of small insect pests. The objective of this work was to compare the biological and reproductive aspects, to determine the thermal requirements and to establish the climatic zoning of four species of lacewings, Chysoperla externa (Hagen), Ceraeochrysa cubana (Hagen), Ceraeochrysa cincta (Schneider) and Ceraeochrysa paraguaria (Navás) for the state of São Paulo. The results showed that the four species of lacewings were able to complete their egg-adult cycle in the thermal range of 18 to 32 °C and the best viability obtained between 22 and 28 °C. It was observed that the Ch. externa species had a faster development than the other species at each stage of development and the egg-adult cycle. In the fertility life table, the population growth was favored in the thermal range of 22 and 28 °C for Ce. cincta, from 22 to 25 °C for Ce. paraguaria, from 25 to 28 °C for Ch. externa and for Ce. cubana temperature at 28 °C. The thermal requirements of the species indicated that the base temperature (Tt) were 10.5, 12.95, 11.99, and 11.77 °C and the thermal constant were 443.81, 362.7, 399.68, and 314.95 DD for Ce. cincta, Ce. cubana, Ce. paraguaria and Ch. externa, respectively. Through the thermal requirements and the use of computational tools such as the Geographic Information System (GIS), it was possible to represent spatially the development of the four species of lacewings. It was observed that the estimated number of monthly generations was influenced by temperature, and in the warmer months the life cycle was faster than in the colder months. Due to the shorter life span of Ch. externa, this species managed to complete 14 generations/year, with the remaining 10 to 11 generations/year in the warmer regions of the state of São Paulo. In colder regions, the number of estimated annual generations for each species was lower. In addition, it was observed that among the species studied, Ch. externa can be indicated for regions with mild to warm temperatures, Ce. cincta for mild climates to cold, Ce. paraguaria for regions with mild temperatures and Ce. cubana regions to warm temperatures. The data obtained in this study could be used for mass rearing the species, to help predict the occurrence of predators in the field and to choose which of the species are best adapted to certain climates in the environment aiming the use of these predators in Integrated Pest Management programs.

Doctor of Philosophy / Department of Entomology / James R. Nechols / Tetranychus kanzawai Kishida and Panonychus citri (McGregor) are the two major arachnid pests of screenhouse-cultivated papayas in Taiwan. Control of these mites has become more difficult because both pests have become resistant to most registered miticides. This laboratory study investigated the feeding behaviors, predatory potential, and prey preference of a domesticated line of Mallada basalis Walker, a commonly-occurring chrysopid in Taiwan, to both of these pest mites. A laboratory assessment on control efficacies of different predator:prey release ratios to single and mixed-pest species was also conducted. Behavioral study showed that all larval stages of M. basalis exhibited a high rate of acceptance of all life stages of both T. kanzawai and P. citri. Second and third instar predators foraged actively during most of the 2-h tests. Numbers and rates of prey consumption were measured for each instar of predator and prey. Results showed that consumption increased and prey handling time decreased as predator life stage advanced, and prey stage decreased. Mallada basalis exhibited both a shorter handling time and corresponding higher consumption rate on P. citri compared with T. kanzawai. Handling time and consumption rate also were positively affected by increasing prey density. Mallada basalis did not exhibit notable species or life stage preferences, and prior feeding experience on one mite species did not affect subsequent prey choice between the two mites. Lacewings significantly reduced T. kanzawai and P. citri populations at a predator:prey ratio of 1:30 and this improved at ratios of 1:15 and 1:10. Control of T. kanzawai was slightly better than P. citri when the mites occurred singly and together. Consumption by M. basalis increased with temperature up to 30C. I conclude that M. basalis has high potential for augmentative biological control of papaya mites. Further field investigations are needed for making final recommendations.

A citricultura orgânica Brasileira tem se destacado no mercado internacional no tocante às exportações de suco e concentrado de laranja, polpa peletizada para alimentação animal e óleos para indústria química e farmacêutica. A calda sulfocálcica vem sendo empregada como produto alternativo para a agricultura orgânica em razão da sua baixa toxicidade se comparada aos inseticidas sintéticos frequentemente usados na agricultura convencional. O presente estudo teve como objetivo avaliar o desempenho de C. externa como predadora de T. citricida em citros tratado com calda sulfocálcica em diferentes concentrações. Especificamente, foi investigada a dinâmica de predação de C. externa sobre T. citricida considerando a inclusão de predadores e presas em citros tratados com calda sulfocálcica. A resposta funcional de C. externa sobre T. citricida também foi analisada com base na teoria ecológica e aplicação de funções não-lineares. A proposta de um modelo matemático para descrever a ação da calda sulfocálcica sobre o sistema trófico foi também incluída no estudo. Dos resultados encontrados pode-se concluir que a concentração de enxofre em 6000 g/mL pode ser prejudicial ao desenvolvimento do crisopídeo, diminuindo significativamente a viabilidade da população. Entretanto, a calda sulfocálcica não altera a capacidade predatória do crisopídeo. No que diz respeito à T. citricida, não parece ser atingida pelas formulações da calda sulfocálcica e também não parece ser presa atrativa ao predador. A regressão logística polinomial indicou resposta funcional do tipo II, caracterizada por uma assíntota que exibe saturação em densidades mais elevadas, tanto para o experimento com a aplicação de calda sulfocálcica quanto para a testemunha. O processo de modelagem resultou em equações em tempo discreto para avaliar o efeito da concentração da calda sulfocálcica sobre a dinâmica predador-presa das espécies envolvidas no estudo. Os resultados obtidos pelas simulações descrevem adequadamente o que foi encontrado nos experimentos, o que sugere boa acurácia dos modelos ao problema investigado. Este tipo de resultado motiva a continuidade dos estudos com foco em modelagem, com vistas ao aperfeiçoamento do modelo. / The Brazilian organic citrus has distinguished itself in the international market as regards to exports of concentrated orange juice, pelletized pulp for animal feeding and oils for chemical and pharmaceutical industry. The lime sulphur has been employed as an alternative product for organic agriculture because of its low toxicity, when compared to synthetic insecticides commonly used in conventional agriculture. This study aimed to evaluate the performance of Chrysoperla externa on its prey Toxoptera citricida in citrus, where lime sulfur was applied in three different concentrations. Specifically, the predation dynamics of C. externa on T. citricida was investigated considering the inclusion of predators and prey in citrus previously treated with lime sulfur. The functional response of C. externa on T. citricida was analyzed based on ecological theory relying on the use of non-linear functions. A mathematical model to describe the action of lime sulphur on the trophic system was also proposed. The results suggest that the concentration of sulphur in 6000 g/mL can be detrimental to the development of green lacewing, significantly reducing the viability of its population. The lime sulphur does not change the predatory ability of the green lacewing. With respect to T. citricida does not seem to be attained by lime sulfur and to show enough attractiveness for the predators larvae development. Polynomial logistic regression indicated type II functional response, which is characterized by an asymptote that exhibits saturation in higher densities for both lime sulphur applied citrus and control citrus. The modeling process resulted in discrete-time equations to evaluate the effect of concentration of lime sulphur on the dynamics of the system. The results obtained by simulations are suitable description for the results experimental found. This suggest a good accuracy of the models to the problem. This kind of result encourage new studies focused on modeling and improvement of the model.

Orientador: Daniela Carvalho dos Santos / Resumo: O biopesticida Azamax™ tem sido utilizado como uma alternativa aos inseticidas sintéticos para o controle de pragas em plantações. Além disso, este produto tem obtido destaque por poder se associar ao uso de predadores naturais no controle biológico previsto pelo Manejo Integrado de Pragas (MIP). Dentre os modelos biológicos, destaca-se a espécie Ceraeochrysa claveri, sobretudo devido sua característica predadora na fase de larva com ampla variedade de presas e alto potencial reprodutivo na fase adulta. Embora a azadiractina, ingrediente ativo do Azamax™, já tenha sido relacionada com a indução de efeitos citotóxicos em insetos, ainda não há dados na literatura sobre os possíveis efeitos da sua ingestão indireta em células germinativas e intestinais de C. claveri. Desta forma, o objetivo deste estudo foi avaliar o efeito tóxico e genotóxico do Azamax™ em células do ovário e do intestino de fêmeas de C. claveri. As larvas foram alimentadas ad libitum, com ovos de Diatraea saccharalis tratados com duas diferentes concentrações do Azamax™ (0,3% e 0,5%) durante todo o seu período larval (n=150 larvas/grupo). As análises morfológicas, ultraestruturais e de genotoxicidade foram realizadas após os indivíduos se desenvolverem até a fase adulta. Os resultados indicaram que a exposição ao Azamax™ somente na fase larval, induziu sinais de toxicidade em todas as fases do desenvolvimento do inseto, como: (a) significante taxa de mortalidade a partir do 3º instar larval; (b) prepupa e pupa... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Azamax ™ biopesticide has been used as an alternative to synthetic insecticides for pest control in several crops. Besides, this product has been highlighted because this association use with natural predators for biological control in the integrated pest management programs (IPM). Among the biological models, is commonly use the specie Ceraeochrysa claveri, above all its predatory characteristic at the larval stage with a wide variety of prey and high reproductive potential in the adult stage. Azadirachtin, active ingredient of Azamax ™, has been related to the induction of cytotoxic effects in insects, although it has not been published in literature about the possible effects of Azamax and its indirect ingestion in germ and intestinal cells of C. claveri. From this, the aim of this study, is to evaluate the toxic and genotoxic effect of Azamax ™ in cells of the ovary and intestine of females of C. claveri. Larvae were fed ad libitum with treated eggs of Diatraea saccharalis at different concentrations of Azamax ™ (0.3% and 0.5%) during all or their larval period (n = 150 larvae/group). Morphological, ultrastructural and genotoxic analyzes carried out when individuals reached adult stage. The results indicated that exposure to Azamax ™ only in the larval phase induced signs of toxicity at all stages of insect development, such as: (a) significant mortality rate from 3rd instar larval; (b) prepupa and pupae inviable; (c) changes in the duration of the phases (larva, prepupa ... (Complete abstract click electronic access below) / Doutor

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.

Resumo: Os crisopídeos são insetos com grande potencial para uso em programas de controle biológico de pragas agrícolas. Populações de Chrysoperla externa apresentam ampla distribuição geográfica, abrangendo desde o sul dos Estados Unidos até o sul da América do Sul, ocorrendo em diferentes ambientes. Contudo, há relativamente poucos estudos buscando compreender a estrutura genética de agentes de controle biológico, especialmente insetos predadores. Desta forma, os principais objetivos deste trabalho foram caracterizar geneticamente as populações de C. externa por meio de sequências do gene mitocondrial COI e compreender sua estrutura populacional nos municípios amostrados no Estado de São Paulo. Para tanto, indivíduos adultos foram coletados em pomares de citros, e da região torácica foi extraído o DNA total. O gene COI foi amplificado por meio da técnica de PCR e as amostras foram purificadas e sequenciadas. As populações de C. externa analisadas apresentaram elevada diversidade genética, bem distribuída entre os municípios amostrados. Esta homogeneização pode ser decorrência de fluxo gênico, ação antrópica, correntes de ar, proximidade das fazendas com matas nativas e elevado potencial reprodutivo de C. externa. A partir dos resultados obtidos é possível inferir que o agroecossistema, por ser um ambiente homogêneo, esteja contribuindo para a perda de estruturação que havia entre estas populações quando elas viviam em ecossistemas nativos, sendo assim, é fundamental que as populações de C. externa sejam estudas neste ambiente, para que possam ser compreendidas em seu habitat de origem e sem a influência da ação antrópica / Abstract: The green lacewings are insects with great potential for use in programs of biological control of agricultural pests. Populations of Chrysoperla externa are widely distributed geographically, being found from the southern United States until the southern South America, occurring in different environments. However, there are relatively few studies trying to understand the genetic structure of biological control agents, especially predatory insects. Thus, the main objectives of this work were to characterize genetically the populations of C. externa through COI mitochondrial gene sequences and to understand its population structure in sampled municipalities in the State of São Paulo. For this purpose, adult individuals were collected in citrus orchards, and from its torax were extracted the total DNA. The COI gene was amplified by PCR and the samples were purified and sequenced. The populations showed high genetic diversity, well distributed among the municipalities. This homogenization may be due to gene flow, human action, action of winds, proximity of farms to native forests, and high reproductive potential of C. externa. From the results, is possible to infer that the agroecosystem, a homogeneous environment, may be contributing to the loss of structure that existed among the populations when they lived in native ecosystems, and therefore, the populations of C. externa must be studied in this environment, so they could be understood in its natural habitat and without the influence of the human action / Orientador: Sérgio de Freitas / Coorientador: Adriana Coletto Morales / Banca: Sergio Antonio de Bortoli / Banca: Fernando de Faria Franco / Mestre

A citricultura orgânica Brasileira tem se destacado no mercado internacional no tocante às exportações de suco e concentrado de laranja, polpa peletizada para alimentação animal e óleos para indústria química e farmacêutica. A calda sulfocálcica vem sendo empregada como produto alternativo para a agricultura orgânica em razão da sua baixa toxicidade se comparada aos inseticidas sintéticos frequentemente usados na agricultura convencional. O presente estudo teve como objetivo avaliar o desempenho de C. externa como predadora de T. citricida em citros tratado com calda sulfocálcica em diferentes concentrações. Especificamente, foi investigada a dinâmica de predação de C. externa sobre T. citricida considerando a inclusão de predadores e presas em citros tratados com calda sulfocálcica. A resposta funcional de C. externa sobre T. citricida também foi analisada com base na teoria ecológica e aplicação de funções não-lineares. A proposta de um modelo matemático para descrever a ação da calda sulfocálcica sobre o sistema trófico foi também incluída no estudo. Dos resultados encontrados pode-se concluir que a concentração de enxofre em 6000 g/mL pode ser prejudicial ao desenvolvimento do crisopídeo, diminuindo significativamente a viabilidade da população. Entretanto, a calda sulfocálcica não altera a capacidade predatória do crisopídeo. No que diz respeito à T. citricida, não parece ser atingida pelas formulações da calda sulfocálcica e também não parece ser presa atrativa ao predador. A regressão logística polinomial indicou resposta funcional do tipo II, caracterizada por uma assíntota que exibe saturação em densidades mais elevadas, tanto para o experimento com a aplicação de calda sulfocálcica quanto para a testemunha. O processo de modelagem resultou em equações em tempo discreto para avaliar o efeito da concentração da calda sulfocálcica sobre a dinâmica predador-presa das espécies envolvidas no estudo. Os resultados obtidos pelas simulações descrevem adequadamente o que foi encontrado nos experimentos, o que sugere boa acurácia dos modelos ao problema investigado. Este tipo de resultado motiva a continuidade dos estudos com foco em modelagem, com vistas ao aperfeiçoamento do modelo. / The Brazilian organic citrus has distinguished itself in the international market as regards to exports of concentrated orange juice, pelletized pulp for animal feeding and oils for chemical and pharmaceutical industry. The lime sulphur has been employed as an alternative product for organic agriculture because of its low toxicity, when compared to synthetic insecticides commonly used in conventional agriculture. This study aimed to evaluate the performance of Chrysoperla externa on its prey Toxoptera citricida in citrus, where lime sulfur was applied in three different concentrations. Specifically, the predation dynamics of C. externa on T. citricida was investigated considering the inclusion of predators and prey in citrus previously treated with lime sulfur. The functional response of C. externa on T. citricida was analyzed based on ecological theory relying on the use of non-linear functions. A mathematical model to describe the action of lime sulphur on the trophic system was also proposed. The results suggest that the concentration of sulphur in 6000 g/mL can be detrimental to the development of green lacewing, significantly reducing the viability of its population. The lime sulphur does not change the predatory ability of the green lacewing. With respect to T. citricida does not seem to be attained by lime sulfur and to show enough attractiveness for the predators larvae development. Polynomial logistic regression indicated type II functional response, which is characterized by an asymptote that exhibits saturation in higher densities for both lime sulphur applied citrus and control citrus. The modeling process resulted in discrete-time equations to evaluate the effect of concentration of lime sulphur on the dynamics of the system. The results obtained by simulations are suitable description for the results experimental found. This suggest a good accuracy of the models to the problem. This kind of result encourage new studies focused on modeling and improvement of the model.

Genetically modified (GM) maize was developed mainly to control lepidopteran pests such as the maize stem borer (Busseola fusca) (Lepidoptera: Noctuidae). Since the first commercialization of GM crops with insecticidal properties, possible non-target effects such as the effect at the third trophic level on important predators for example lacewing species (Chrysoperla spp.) have been of concern. Contradicting results were reported in previous studies with regard to the effect of Cry 1Ab protein produced by Bt maize on the performance of lacewings. Some studies found that Bt proteins had no effect while others reported that C. carnea performed poorly if they consumed prey that consumed Cry 1Ab protein. In South Africa one of the most common chrysopid species in maize ecosystems is Chrysoperla pudica (Navás) (Neuroptera: Chrysopidae). Evolution of Bt resistant pests, such as B. fusca in South Africa facilitates a new pathway for exposure of predators to healthy prey that consumes Cry 1Ab proteins. The aims of this study was to determine the effect of the Cry 1Ab protein expressed in Bt maize on a non-target organism‟s (C. pudica) biology via indirect exposure, and to determine the concentration of Cry 1Ab protein in the plant, prey and predator. Chrysoperla pudica larvae were indirectly exposed to the Bt-toxin through healthy Bt-maize feeding prey (B. fusca larvae) in two feeding experiments and lacewing survival and life history parameters recorded. Bt had a limited effect on some parameters that were evaluated. The larval and pupal periods of C. pudica larvae that were exposed to the Bt-toxin had a significant difference from that of the control treatment. The Bt-toxin had a significant effect on fecundity, fertility and malformation after emergence of C. pudica adults of which larvae fed only on Bt resistant B. fusca larvae, but not on the mortality rate. Cry 1Ab concentration was the highest in the plant, followed by the prey and lacewing larvae. This study showed that the Cry 1Ab protein had a slight adverse effect only on certain life parameters of C. pudica, and that Cry 1Ab protein was hardly detectable in C. pudica larvae. However, since this study represented a worst-case scenario where diverse prey was not available, insignificant effects is expected under field conditions where prey is diverse. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2014