Etnoecologia e controle biológico conservativo em cafeeiros sob sistemas agroflorestais

• Autor(a) principal: Rezende, Maíra Queiroz
• Data de Publicação: 2010
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/3933
• topic: Nectário extrafloral; Inimigos naturais; Etnoentomologia; Bicho-mineiro do cafeeiro; Broca-do-café; Extrafloral nectaries; Natural enemies; Ethnoecology; The coffee leafminer; Coffee berry borer; CNPQ::CIENCIAS BIOLOGICAS::ECOLOGIA::ECOLOGIA APLICADA

The aim of this work was to reconcile scientific and popular knowledge to assess the possibility of using the inga tree in coffee agroecosystems as a strategy for conservation biological control. The goals of the first chapter were to register the perception of small farmers who grow coffee in agroforestry systems in the municipality of Araponga, Minas Gerais, Brazil, of the term "insect" and the interactions of these insects with agroecosystems; to describe the knowledge of uses of insects by these farmers; and to list which plants are used by these farmers in the diversification of agroforestry systems with the purpose to control of coffee pests. Five farmers were interviewed through semi-structured questionnaires and free listings. The semantic domain "insect" was used by these farmers as a wide ethnotaxonomic category, joining various organisms such as annelids, mollusks and fungi. They recognized positive and negative interactions between insects and coffee, but they did not consider these insect as pests. They listed 12 ethnocategories of insects that damage the coffee crop; the "coffee leafminer" was cited most. The farmers recognized 11 "insects" usable as food source, for soil fertilization, pest control, medicine and as an indicator of environmental quality. They recognized 18 plants that help in management of coffee pests. The pest control was associated with the attraction or repellence of insects by plants, or improving soil quality which increases the resistance of coffee against pests. Several other uses of plants were mentioned, which explain the use of these species in the farms. The inga tree was cited most frequently and with more diversified functions. Ingas have extrafloral nectaries (EFNs) that can attract natural enemies by providing alternative food, thus protect the tree against herbivory. Little is known about the effect of EFNs on neighbouring plants. Thus, the goals of the second chapter of this study were to assess the possible effect of EFNs in reducing herbivory by the coffee leafminer, Leucoptera coffeella (Mèneville-Guerin) and coffee berry borer, Hypothenemus hampei (Ferrari) on coffee crops and to identify the major insect groups involved in this process. The effects of EFNs on parasitism of the coffee leafminer were evaluated through a correlative study. This study was conducted in five agroforestry systems in the county of Araponga, MG. In each system, 30 leaves of five inga trees were sampled every two hours during the day. All arthropods were collected with suction, identified and categorized by their functional groups: predators, predatory ants, parasitoids and herbivores. For the assessment of damage, the frequencies of mined leaves and bored fruits were calculated. For the collection of natural enemies and to estimate the parasitism in mined leaves, we collected leaves with mines, which were incubated until emergence of adult L. coffeella or parasitoids. All samples were collected in transects of 10 meters starting from each inga tree sampled, in order to evaluate the effect of the distance from the inga tree on these variables. A total of 747 and 165 morphospecies were found to visit the EFNs. Among these visitors were natural enemies of coffee pests. The abundance of different insect groups varied throughout the hours. Ants and predators were more abundant at midday and parasitoids at afternoon. The abundance of parasitoids in the EFNs was positively influenced by the abundance of ants. The frequency of bored fruits decreased only with the richness of parasitoids and abundance of predators at the EFNs. The richness and abundance of natural enemies in inga's EFNs did not influence the frequency of mined leaves. Seven species of parasitoid of L. coffeella were collected at the agroforestry systems. The frequency of parasitism in mined leaves increased with the abundance of predators and ants in inga trees and showed no correlation with the richness and abundance of the other natural enemies. The distance from the inga trees did not influence the damage caused by herbivory or parasitism of the coffee leafminer. The results indicate that multitrophic interactions are influenced by the EFNs of the inga and it affects the herbivory in the coffee crops. It can be concluded that inga trees attract and offer alternative food for potential natural enemies of coffee pests, reducing the damage caused by the coffee berry borer and increasing parasitism in the coffee leafminer. Therefore, the use of inga tree in coffee agroecosystems may be a good strategy for conservation biological control.