Helicoverpa armigera e Spodoptera frugiperda (Lepidoptera: Noctuidae): Dieta artificial, produtos para controle e efeitos em polinizadores
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2020-03-20
Autores
Truzi, Caio Cesar [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Helicoverpa armigera (Hübner, 1808) e Spodoptera frugiperda (J.E. Smith, 1797) (Lepidoptera: Noctuidae) são insetos cosmopolitas, polífagos e que causam danos tanto na fase vegetativa quanto na reprodutiva de vários cultivos. Entre os métodos disponíveis para controle, os mais utilizados são o químico e a utilização de plantas Bt, porém o uso incorreto resultou em diversos relatos de resistência a esses dois métodos. Deste modo, surgiu a necessidade de novas tecnologias e produtos para o controle desses insetos-praga, sendo que o controle biológico com bactérias e vírus, e extratos de plantas podem ser ferramentas importantes frente a esses problemas. Além da resistência, outro problema que o uso incorreto dos inseticidas pode causar é a toxicidade a organismos não alvo, como as abelhas Apis mellifera Linnaeus, 1758 (Hymenoptera: Apidae), que vem sofrendo com a mortalidade causada por esses produtos. Para a realização de pesquisas que auxiliem e aprimorem os programas de Manejo Integrado de H. armigera e S. frugiperda, é essencial uma metodologia de criação que permita a obtenção de uma grande quantidade de indivíduos, sendo que dietas artificiais adequadas auxiliam a criação em grande escala. Neste sentido, o objetivo deste trabalho foi investigar o efeito de diferentes níveis proteicos na dieta artificial para criação destas espécies, o efeito agudo das concentrações letais e os efeitos subletais de inseticidas químicos, biológicos e de extrato da planta Piper cubeba Linnaeus, 1753 (Piperales: Piperaceae) em H. armigera e S. frugiperda, além da toxicidade por contato e ingestão desses produtos para A. mellifera, bem como avaliar a fitotoxicidade do extrato em plantas de milho e soja. Foram avaliadas 3 formulações de dieta artificial, sendo uma utilizada na criação de rotina e duas modificadas, com o dobro da quantidade de proteína e com a metade. Os teores proteicos mais baixos ou mais elevados na dieta de H. armigera afetaram negativamente os aspectos biológicos e nutricionais da espécie, enquanto S. frugiperda não teve seu crescimento populacional afetado, podendo ser utilizada a dieta com menor quantidade de proteína para redução no custo de criação. Visando fornecer informações ao manejo desses lepidópteros-praga, foi utilizado o inseticida químico flubendiamida (Belt®), os biológicos VPN-HzSNPV (Diplomata®), VPN-SfMNPV (CartuchoVIT®) e Bacillus thuringiensis subsp. aizawai (XenTari®) e o extrato hexânico de P. cubeba. O extrato de P. cubeba apresentou atividade inseticida apenas para lagartas de S. frugiperda, com mortalidade de 90,0%, e ação de repelência para ambas as espécies. Ao avaliar os parâmetros biológicos e os índices de consumo e utilização de alimento sob influência das concentrações subletais (CL25 e CL10), verificou-se que os inseticidas causaram alterações no período larval e pupal, no peso de pupas e na fecundidade, além de alterações no crescimento populacional e no comportamento de alimentação. Os produtos utilizados não causaram mortalidade significativa em A. mellifera por contato, entretanto por ingestão, após 48 horas, verificou-se maior mortalidade das abelhas com o bioinseticida à base de Bt, enquanto os menores percentuais de mortalidade foram observados com o produto químico flubendiamida e com o baculovírus, VPN-SfMNPV, resultando também em maior número de visitas e de ingestão de alimento pelos insetos, por outro lado os menores valores de visita e ingestão foram para o extrato de P. cubeba. Espera-se que os resultados obtidos nesta tese forneçam subsídios para auxiliar a obtenção de insetos de qualidade para pesquisas, além de implementar alternativas para o controle de H. armigera e S. frugiperda em culturas de grande importância econômica, sem causar problemas às abelhas polinizadoras.
Helicoverpa armigera (Hübner, 1808) and Spodoptera frugiperda (J.E. Smith, 1797) (Lepidoptera: Noctuidae) are cosmopolitan, polyphagous insects that cause damage both in the vegetative and in the reproductive phase of several crops. Among the methods available for its control, the most used are the chemical and the use of Bt plants, however the incorrect use has resulted in several reports of resistance to both methods. Thus, there was a need to development of new technologies and products for the control of these pest insect, and biological control with bacteria and viruses, and plant extracts can be important tools in the face of these problems. In addition to resistance, another problem that the incorrect use of pesticides can cause is toxicity to non-target organisms, such as honey bees Apis mellifera Linnaeus, 1758 (Hymenoptera: Apidae), which has been suffering from the mortality caused by these products. In order to carry out research that helps and improve the Integrated Management programs of H. armigera e S. frugiperda, a rearing methodology is essential that allows the obtaining of a large number of individuals, and adequate artificial diets assist the rearing on a large scale. In this sense, the aim of this research was to investigate the effect of diferente protein levels in the artificial diet for the rearing of these species, the acute effect of lethal concentrations and the sublethal effects of chemical and biological pesticides, and plant extract from the plant Piper cubeba Linnaeus, 1753 (Piperales: Piperaceae) on H. armigera and S. frugiperda, in addition to the contact and ingestion toxicity of these products to A. mellifera, as well as to evaluate the phytotoxicity of the extract in maize and soybean plants. Three formulations of artificial diet were evaluated, one used in routine rearing and two modified, with double amount of protein and the other with half. The lower or higher levels in the diet of H. armigera negatively affected the biological and nutritional aspects of the species, while S. frugiperda did not have its population growth affected, and the diet with lower protein level can be used to reduce the cost of rearing. In order to provide information on the management of these lepidopteran pests, the chemical pesticide flubendiamide (Belt®), the biological NPV-HzSNPV (Diplomata®), NPV-SfMNPV (CartuchoVIT®) and Bacillus thuringiensis subsp. aizawai (XenTari®) and the hexane extract of P. cubeba. The extract of P. cubeba showed insecticidal activity only for S. frugiperda larvae, with mortality of 90,0%, and repellent action for both species. When evaluating the biological parameters and the food consumption utilization indexes under influence of sublethal concentrations (LC25 and LC10), it was found that the pesticides caused changes in the larval and pupal periods, in the pupae weight and fertility, in addition to changes population growth and feeding behavior. The products used did not cause significant mortality in A. mellifera by contact, however by ingestion, after 48 hours, there was a higher mortality of honey bees with the Bt-based biopesticide, while the lowest percentages of total mortality were observed in the chemical product flubendiamide and the baculovirus, NPV-SfMNPV, also resulting in a higher number of visits and food intake by insects, on the other hand the lowest values of visit and intake were for the extract of P. cubeba. It is hoped that the results obtained in this thesis will provide help to obtain quality insects for researches, in addition to implementing alternatives for the control of H. armigera and S. frugiperda in cultures of great economic importance, without problems to pollinating bees.
Helicoverpa armigera (Hübner, 1808) and Spodoptera frugiperda (J.E. Smith, 1797) (Lepidoptera: Noctuidae) are cosmopolitan, polyphagous insects that cause damage both in the vegetative and in the reproductive phase of several crops. Among the methods available for its control, the most used are the chemical and the use of Bt plants, however the incorrect use has resulted in several reports of resistance to both methods. Thus, there was a need to development of new technologies and products for the control of these pest insect, and biological control with bacteria and viruses, and plant extracts can be important tools in the face of these problems. In addition to resistance, another problem that the incorrect use of pesticides can cause is toxicity to non-target organisms, such as honey bees Apis mellifera Linnaeus, 1758 (Hymenoptera: Apidae), which has been suffering from the mortality caused by these products. In order to carry out research that helps and improve the Integrated Management programs of H. armigera e S. frugiperda, a rearing methodology is essential that allows the obtaining of a large number of individuals, and adequate artificial diets assist the rearing on a large scale. In this sense, the aim of this research was to investigate the effect of diferente protein levels in the artificial diet for the rearing of these species, the acute effect of lethal concentrations and the sublethal effects of chemical and biological pesticides, and plant extract from the plant Piper cubeba Linnaeus, 1753 (Piperales: Piperaceae) on H. armigera and S. frugiperda, in addition to the contact and ingestion toxicity of these products to A. mellifera, as well as to evaluate the phytotoxicity of the extract in maize and soybean plants. Three formulations of artificial diet were evaluated, one used in routine rearing and two modified, with double amount of protein and the other with half. The lower or higher levels in the diet of H. armigera negatively affected the biological and nutritional aspects of the species, while S. frugiperda did not have its population growth affected, and the diet with lower protein level can be used to reduce the cost of rearing. In order to provide information on the management of these lepidopteran pests, the chemical pesticide flubendiamide (Belt®), the biological NPV-HzSNPV (Diplomata®), NPV-SfMNPV (CartuchoVIT®) and Bacillus thuringiensis subsp. aizawai (XenTari®) and the hexane extract of P. cubeba. The extract of P. cubeba showed insecticidal activity only for S. frugiperda larvae, with mortality of 90,0%, and repellent action for both species. When evaluating the biological parameters and the food consumption utilization indexes under influence of sublethal concentrations (LC25 and LC10), it was found that the pesticides caused changes in the larval and pupal periods, in the pupae weight and fertility, in addition to changes population growth and feeding behavior. The products used did not cause significant mortality in A. mellifera by contact, however by ingestion, after 48 hours, there was a higher mortality of honey bees with the Bt-based biopesticide, while the lowest percentages of total mortality were observed in the chemical product flubendiamide and the baculovirus, NPV-SfMNPV, also resulting in a higher number of visits and food intake by insects, on the other hand the lowest values of visit and intake were for the extract of P. cubeba. It is hoped that the results obtained in this thesis will provide help to obtain quality insects for researches, in addition to implementing alternatives for the control of H. armigera and S. frugiperda in cultures of great economic importance, without problems to pollinating bees.
Descrição
Palavras-chave
Criação de insetos, Extratos vegetais, Inseticidas, Toxicidade, Organismo não alvo, Insect rearing, Plant extracts, Insecticides, Toxicity, Non-target organism