Orientador: Carlos Frederico Wilcken / Banca: Edson Luiz Lopes Baldin / Banca: Nádia Cristina de Oliveira / Banca: Luiz Alexandre Nogueira de Sá / Banca: Leonardo Rodrigues Barbosa / Resumo: O gênero Eucalyptus (Myrtaceae) é originário da Austrália e hospeda várias espécies de insetos da família Psyllidae. Dentre elas, o psilídeo-de-concha Glycaspis brimblecombei Moore (Hemiptera: Psyllidae), que é considerada uma das principais pragas introduzidas desta cultura no Brasil e em outros países. O parasitóide Psyllaephagus bliteus Riek (Hymenoptera: Encyrtidae) é indicado como principal agente no controle biológico desta praga. Devido a sua importância econômica, esse trabalho objetivou estudar as populações de G. brimblecombei e de P. bliteus em floresta de Eucalyptus camaldulensis para determinação de sua distribuição espacial, flutuação populacional, a relação com fatores meteorológicos (temperatura e precipitação), e determinar o índice de parasitismo pós liberação de P. bliteus em campo. O estudo da dinâmica populacional do psilídeo-de-concha e do seu parasitóide foi realizado através da utilização de 53 armadilhas amarelas e da coleta de 53 ramos/avaliação em um talhão de 19 ha com E. camaldulensis em Luiz Antônio, SP, com 42 avaliações, entre janeiro de 2006 a janeiro de 2008. Concluiu-se que as populações de ambas espécies apresentaram distribuição espacial agregada, possuem correlação inversamente proporcional à temperatura, e a precipitação pluviométrica; ocorreu aumento no índice de parasitismo em todos os pontos de liberação de P. bliteus. no período avaliado / Abstract: The genus Eucalyptus is originally from Australia and hosts several species of insects of the family Psylidae. Among them, the red gum lerp psyllid is considered one of the main pests of this crop introduced in Brazil and other countries. However, for the control of phytophagous hemiptera, the treatment with insecticides proved to be expensive and unsustainable. The psylllid specific parasitic wasp Psyllaephagus bliteus Riek (Hymenoptera: Encyrtidae) is indicated as the main biological control agent of this pest. Due to its economic importance, this study aimed to evaluate G. brimblecombei and P. bliteus population in Eucalyptus camaldulensis plantations to determine their spatial distribution, population fluctuation with weather interactions (temperature and rainfall), and also to determine parasitism rates in the field after release of P. bliteus. The study of population dynamic of red gum lerp psyllid and its parasitoid (53 traps sampled and 53 branches sampled per sampling dates) was carried out on E. camaldulensis plantations in 19 ha area in Luiz Antônio municipality (SP, Brazil), from January 2006 to January 2008 (42 sampling dates). This research indicated that population of both species noticed especial aggregated distribution, inversely proportional subject to temperature. Besides, was found correlation between both species and rainfall. There was also at measured period an increase in the parasitism rate at all release points of P. bliteus / Doutor

Made available in DSpace on 2014-06-11T19:35:01Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-05-28Bitstream added on 2014-06-13T19:44:47Z : No. of bitstreams: 1 ferreirafilho_pj_dr_botfca.pdf: 1155400 bytes, checksum: 8e9b3a892a4bc9b6e2a50c148430127a (MD5) / O gênero Eucalyptus (Myrtaceae) é originário da Austrália e hospeda várias espécies de insetos da família Psyllidae. Dentre elas, o psilídeo-de-concha Glycaspis brimblecombei Moore (Hemiptera: Psyllidae), que é considerada uma das principais pragas introduzidas desta cultura no Brasil e em outros países. O parasitóide Psyllaephagus bliteus Riek (Hymenoptera: Encyrtidae) é indicado como principal agente no controle biológico desta praga. Devido a sua importância econômica, esse trabalho objetivou estudar as populações de G. brimblecombei e de P. bliteus em floresta de Eucalyptus camaldulensis para determinação de sua distribuição espacial, flutuação populacional, a relação com fatores meteorológicos (temperatura e precipitação), e determinar o índice de parasitismo pós liberação de P. bliteus em campo. O estudo da dinâmica populacional do psilídeo-de-concha e do seu parasitóide foi realizado através da utilização de 53 armadilhas amarelas e da coleta de 53 ramos/avaliação em um talhão de 19 ha com E. camaldulensis em Luiz Antônio, SP, com 42 avaliações, entre janeiro de 2006 a janeiro de 2008. Concluiu-se que as populações de ambas espécies apresentaram distribuição espacial agregada, possuem correlação inversamente proporcional à temperatura, e a precipitação pluviométrica; ocorreu aumento no índice de parasitismo em todos os pontos de liberação de P. bliteus. no período avaliado / The genus Eucalyptus is originally from Australia and hosts several species of insects of the family Psylidae. Among them, the red gum lerp psyllid is considered one of the main pests of this crop introduced in Brazil and other countries. However, for the control of phytophagous hemiptera, the treatment with insecticides proved to be expensive and unsustainable. The psylllid specific parasitic wasp Psyllaephagus bliteus Riek (Hymenoptera: Encyrtidae) is indicated as the main biological control agent of this pest. Due to its economic importance, this study aimed to evaluate G. brimblecombei and P. bliteus population in Eucalyptus camaldulensis plantations to determine their spatial distribution, population fluctuation with weather interactions (temperature and rainfall), and also to determine parasitism rates in the field after release of P. bliteus. The study of population dynamic of red gum lerp psyllid and its parasitoid (53 traps sampled and 53 branches sampled per sampling dates) was carried out on E. camaldulensis plantations in 19 ha area in Luiz Antônio municipality (SP, Brazil), from January 2006 to January 2008 (42 sampling dates). This research indicated that population of both species noticed especial aggregated distribution, inversely proportional subject to temperature. Besides, was found correlation between both species and rainfall. There was also at measured period an increase in the parasitism rate at all release points of P. bliteus

Thesis. (M. A. Agriculture (Agricultural Economics)) -- University of Limpopo, 2022 / Food security, poverty and hunger issues, as well as methods of addressing remain a concern for many South Africans. Smallholder farmers' agricultural production is seen as the key to simultaneously alleviating poverty and ensuring food security, especially in rural areas. The sweet potato crop is commonly produced by smallholder farmers in rural areas as a staple in many South African households with the potential to reduce hunger and poverty. Nevertheless, just like other crops, the sweet potato is impaired by external factors such as extreme weather conditions, insects, pests and diseases, thus threatening food security. The most destructive pest to sweet potatoes acknowledged in the literature is the sweet potato weevil (SPW), which can cause between 5-100% in areas where it is not controlled. While there are many SPW control measures Entomopathogenic Nematodes (EPNs) are emerging as one of the Integrated Pest Management (IPM) bio-control techniques that have shown promise in controlling SPW infestations in South Africa and globally. This study conducts a socio-economic analysis of smallholder sweet potato production and analyses the acceptability of EPNs as bio-control measures against the SPW in the Gauteng, Limpopo and North West Provinces of South Africa. This was done through an assessment of farmers‘ knowledge, attitudes, perception and practices (KAPP analysis), exploration of the acceptability of EPNs by farmers, determination of and factors influencing profitability and technical efficiency. Primary data was collected from 119 respondents who were selected through non-probability sampling techniques; purposive, census, and snowball. The analytical tools used to analyse the data were descriptive statistics, Gross Margin Analysis, Multiple linear regression model, Data Envelopment Analysis (DEA) and the Tobit regression model. From the results, an average knowledge score of 2.30 based on a 3–point Likert scale revealed that sweet potato farmers are knowledgeable of the SPW, the impacts and the control measures. Despite this level of knowledge, the farmers were impartial about the attitudes and perceptions regarding the SPW and the control measures. This was based on the findings of a 5-point Likert scale, which yielded average scores of 2.53 and 2.74, respectively. The study also revealed that the majority of the farmers prefer the use of indigenous and physical practices to control SPW. With regards to acceptance of the EPNs bio-control innovation towards control of the SPW, a mean Composite Index of Acceptancy (CIA) of 0.77 revealed the willingness of farmers to accept the EPNs as a bio-control measure. A Gross margin of R9 552.37 indicates that sweet potato farming is generally profitable, and this is influenced by socio-economic factors such as marital status, employment status, sweet potato output per cycle and access to machinery. On the other hand, while sweet potato farming was found to be profitable, the DEA score of 0.09 reveals that these farmers are technically inefficient. Their technical inefficiency is influenced by sweet potato output per cycle, gross margins, farm size, and access to credit, employment status, and chemical use. Based on these findings, the study recommends farmers‘ support through capacity development initiatives for the sweet potato farmers with regards to general economics of sweet potato production and marketing to maximise and sustain their revenue generation, as well as their general efficiency. In addition, increased training and awareness of the EPNs and their benefits as bio-control measures towards SPW infestation will work towards changing farmers‘ mindset with regard to SPW control measures. / Department of Social Innovation (DSI) and United States Agency for International Development (USAID)