Dinâmica dos fatores naturais de mortalidade de Diatraea saccharalis (Fabricius, 1794) (Lepidoptera: Crambidae) em cana-de-açúcar adjacentes a fragmentos de florestas
Carregando...
Data
2021-07-30
Autores
Oliveira, Sabrina Juvenal de
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
Os ambientes não agrícolas, como florestas e matas, servem de abrigo para organismos que são responsáveis por diversos serviços ecossistêmicos, podendo contribuir com cultivos próximos a esses. No estado de São Paulo, canaviais adjacentes a fragmentos de floresta da Mata Atlântica são encontrados e, dessa forma, a regulação de pragas pode ser favorecida nestas condições. Assim, o objetivo deste trabalho foi analisar a influência de fragmentos florestais na dinâmica dos fatores de mortalidade de ovos e larvas de Diatraea saccharalis (Fabricius, 1794) (Lepidoptera: Crambidae) em cana-de-açúcar com o uso de tabelas de vida ecológicas. Para isso, coortes de ovos e larvas da broca da cana-de-açúcar foram acompanhadas em talhões de canaviais adjacentes a dois tipos de fragmentos de floresta (Plateau e Galeria) e em duas distâncias (5 e 100m) desses fragmentos. Os dados coletados foram utilizados para construção da tabela de vida ecológica e determinação dos principais fatores de mortalidade em cada situação analisada. Para a fase de ovo, os fatores de mortalidade foram classificados em inviabilidade por infertilização, predação, parasitismo, dessecação e desalojamento. Os fatores naturais de mortalidade que não puderam ser caracterizados foram agrupados como desconhecidos. Em ambas as safras houve diferença entre os fatores naturais de mortalidade de D. saccharalis, em que o fator predação se diferenciou dos demais. As formigas (Hymenoptera: Formicidae) e os crisopídeos (Chrysopidae: Neuroptera) foram os agentes predadores mais frequentes. Para a fase larval os fatores de mortalidade foram classificados em predação, parasitismo, afogamento e desconhecido, em que o agrupamento desconhecido se diferenciou dos demais. Além disso, observações de larvas neonatas demonstraram que a predação, a movimentação larval e o deslocamento causado pelo vento estão incluídos no agrupamento de fatores chamados de ‘desconhecido’. Em ambas as safras e estágios de desenvolvimento acompanhados não houve diferença entre a mortalidade nos dois tipos de fragmentos florestais ou entre as duas distâncias da mata. A presença dos fragmentos florestais não contribui para aumentar o controle natural da broca da cana-de-açúcar, mas pode sustentar populações dos inimigos naturais em condições ambientais adversas, garantindo a conservação dos predadores nas paisagens agrícolas e sua posterior recolonização. Por fim, os resultados relatados contribuem para a compreensão da dinâmica populacional de D. saccharalis em campo, demonstram os seus principais agentes reguladores e auxiliam na escolha de táticas de manejo contra a espécie-praga.
Non-agricultural environments, such as forests and woodlands, can offer shelter for organisms that are responsible for several ecosystem services, that might benefit crops near them. In São Paulo state, sugarcane fields are found next to fragments of Atlantic Forest, and thus, pest regulation can be favored under these conditions. Therefore, the objective of this research was to analyze the influence of forest fragments on the dynamics of mortality factors for eggs and larvae of Diatraea saccharalis (Fabricius, 1794) (Lepidoptera: Crambidae) in sugarcane with an ecological life table. For this experiment cohorts of eggs and larvae of the sugarcane borer were observed in stands of sugarcane field adjacent to two types of forest fragments (Plateau and Gallery) on two distances (5 and 100m) from those fragments. The data collected was used to make the ecological life table and determine the main mortality factors in each circumstance analyzed. In the egg stage, mortality factors were classified as unfeasibility due to the eggs not being fertilized, predation, parasitism, desiccation and displacement. Natural mortality factors that could not be characterized were grouped as unknown. On both crops, there was a difference between the natural mortality factors of D. saccharalis, in which the predation factor was different from the others. Ants (Hymenoptera: Formicidae) and lacewings (Chrysopidae: Neuroptera) were the most frequent predators. In the larval stage, the mortality factors were classified as predation, parasitism, drowning and unknown in which the unknown grouping differed from the others. Besides that, observations of neonate larvae revealed that predation, larval movement and wind displacement are included in the classification unknown. In both years and stages of development observed, there was no difference in the mortality on both types of forest fragments and distances. The presence of forest fragments did not contribute to increasing the natural control of the sugarcane borer, but it can still sustain populations of natural predators in adverse environmental conditions, ensuring the conservation of predators in agricultural landscapes and their subsequent recolonization. Finally, the results observed contribute to the understanding of the population dynamics of D. saccharalis in the field, while also indicating their main regulatory agents and help in choosing better management tactics against the sugarcane borer.
Non-agricultural environments, such as forests and woodlands, can offer shelter for organisms that are responsible for several ecosystem services, that might benefit crops near them. In São Paulo state, sugarcane fields are found next to fragments of Atlantic Forest, and thus, pest regulation can be favored under these conditions. Therefore, the objective of this research was to analyze the influence of forest fragments on the dynamics of mortality factors for eggs and larvae of Diatraea saccharalis (Fabricius, 1794) (Lepidoptera: Crambidae) in sugarcane with an ecological life table. For this experiment cohorts of eggs and larvae of the sugarcane borer were observed in stands of sugarcane field adjacent to two types of forest fragments (Plateau and Gallery) on two distances (5 and 100m) from those fragments. The data collected was used to make the ecological life table and determine the main mortality factors in each circumstance analyzed. In the egg stage, mortality factors were classified as unfeasibility due to the eggs not being fertilized, predation, parasitism, desiccation and displacement. Natural mortality factors that could not be characterized were grouped as unknown. On both crops, there was a difference between the natural mortality factors of D. saccharalis, in which the predation factor was different from the others. Ants (Hymenoptera: Formicidae) and lacewings (Chrysopidae: Neuroptera) were the most frequent predators. In the larval stage, the mortality factors were classified as predation, parasitism, drowning and unknown in which the unknown grouping differed from the others. Besides that, observations of neonate larvae revealed that predation, larval movement and wind displacement are included in the classification unknown. In both years and stages of development observed, there was no difference in the mortality on both types of forest fragments and distances. The presence of forest fragments did not contribute to increasing the natural control of the sugarcane borer, but it can still sustain populations of natural predators in adverse environmental conditions, ensuring the conservation of predators in agricultural landscapes and their subsequent recolonization. Finally, the results observed contribute to the understanding of the population dynamics of D. saccharalis in the field, while also indicating their main regulatory agents and help in choosing better management tactics against the sugarcane borer.
Descrição
Palavras-chave
Controle natural de pragas, Ecologia de paisagem, Serviços ecossistêmicos