Desenvolvimento biológico, danos diretos e indiretos da cochonilha rosada da cana-de-açúcar Saccharicoccus sacchari (Cockerell, 1895) (Hemiptera: Pseudococcidae) no estado de São Paulo : biossistemática da cochonilha rosada da cana-de-açúcar
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Data
2022-09-15
Autores
Monteiro, Gabriel Gonçalves [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O cultivo de cana-de-açúcar Saccharum spp. (Poales: Poaceae) faz do Brasil o maior produtor mundial. Apesar de estratégias agronômicas empregadas, problemas fitossanitários como insetos-praga e doenças fitopatogênicas se destacam. A cochonilha-rosada-da-cana-de-açúcar Saccharicoccus sacchari (Cockerell, 1895) (Hemiptera: Pseudococcidae) e o fungo da podridão vermelha Colletotrichum falcatum Went, são comumente encontrados na canavicultura. Para compreender a atuação de um inseto-praga, relacionado ou não com um agente fitopatogênico, necessita-se estudar seu desenvolvimento biológico e os danos diretos e indiretos que ele pode ocasionar. Este trabalho objetivou avaliar o desenvolvimento biológico de S. sacchari em diferentes temperaturas, analisar as características biométricas e tecnológicas dos diferentes estádios fenológicos de plantas de cana-de-açúcar, infestadas pela cochonilha, estimar o número de perfurações ocasionadas pelo pseudococcídeo através de diferentes números do inseto e confirmar por Microscopia Eletrônica de Varredura (MEV) o complexo cochonilha-podridão. Para a análise do desenvolvimento biológico, foram coletadas fêmeas oviplenas e colmos de cana-de-açúcar. Os colmos foram infestados com cochonilhas, individualizados em placas de Petri e mantidos em duas BODs (23 °C ± 2 °C e 28 °C ± 2 °C). Diariamente registrou-se o número de ovos, ovos viáveis e inviáveis, tempo de incubação, duração da última oviposição, eclosão de ninfas, duração de cada ínstar, mortalidade de ninfas, tempo de emergência e longevidade do adulto. O pseudococcídeo se reproduz por partenogênese telítoca. Em condições laboratoriais, o aumento da temperatura favorece a longevidade do inseto com três fases de crescimento. No estudo dos danos diretos, plantas de cana-de-açúcar foram infestadas, em cada estádio fenológico, por cochonilhas oviplenas. As plantas foram submetidas à biometria externa, e, no estádio de maturação, se obteve os dados tecnológicos. Obteve-se que as infestações do inseto em todos estádios fenológicos reduzem as características físicas das plantas, mas não as químicas tecnológicas qualitativas. Para o estudo das perfurações e do complexo cochonilha-podridão, colmos fragmentados foram infestados com diferentes números do pseudococcídeo por progressão geométrica, e colmos infestados pelo pseudococcídeo e infectados por C. falcatum foram coletados. Os colmos de cada tratamento foram imergidos em solução de fucsina ácida 1% e realizada a contagem de perfurações. Amostras isoladas da cochonilha-rosada-da-cana-de-açúcar, do pseudococcídeo com o aparelho bucal nas plantas, do fungo da podridão-vermelha, e do complexo cochonilha-podridão foram observadas sob Microscopia Eletrônica de Varredura (MEV). Verificou-se que as perfurações ocasionadas por S. sacchari variaram entre 5,3 e 30,3, sendo dependente das perfurações de prova, do número de indivíduos, da área disponível para a alimentação e da sobrevivência das ninfas de primeiro, segundo e terceiro ínstares que conseguiram atingir até a fase adulta. Confirma-se a veracidade da hipótese do complexo cochonilha-podridão em plantas de cana-de-açúcar.
The sugarcane crop Saccharum spp. (Poales: Poaceae) makes Brazil the world's largest producer. Despite of agronomic strategies used, phytosanitary issues such as insect pests and phytopathogenic diseases stand out. The pink sugarcane mealybug Saccharicoccus sacchari (Cockerell, 1895) (Hemiptera: Pseudococcidae) and the red rot fungus Colletotrichum falcatum Went are commonly found in sugarcane crops. In order to understand the performance of the insect pest, related or not to a phytopathogenic agent, it is necessary to study its biological development and the direct and indirect damages that it can cause. This study aimed to evaluate the biological development of S. sacchari under different temperatures, to analyze the biometric and technological characteristics in different phenological stages of sugarcane plants, infested by the mealybug, and to estimate the perforations caused by the pseudococcid through different numbers of the insect and to confirm by Scanning Electron Microscopy (SEM) the mealybug-rot complex. For the analysis of the biological development, gravid females and sugarcane stalks were collected. The stalks were infested with mealybugs, individualized in Petri dishes and kept in two BODs (23 °C ± 2 °C and 28 °C ± 2 °C). The number of eggs, viable and nonviable eggs, incubation time, timing of the last oviposition, nymph hatching, timing of each instar, mortality of nymphs, emergence time and adult longevity were recorded daily. Pseudococcids reproduce by thelytocal parthenogenesis. Under laboratory conditions, the increase in temperature favors the longevity of the insect with three phases of growth. In the study of direct damage, sugarcane plants were infested, at each phenological stage, by gravid mealybugs. The plants were submitted to external biometrics, and in the ripening stage, the technological data were obtained. It was found that the insect infestations at all phenological stages reduce the physical characteristics of the plants, but not the qualitative technological chemistry. To accomplish the last objective, fragmented stems were infested with different numbers of the pseudococcid by geometric progression, and stems infested by the pseudococcid and infected by C. falcatum were collected. The stalks from each treatment were immersed in 1% acid fuchsin solution and the holes were counted. Isolated samples of the pink sugarcane mealybug, the pseudococcid with the mouthparts in plants, the red rot fungus and the mealybug-rot complex were observed under Scanning Electron Microscopy (SEM). It was obtained that the number of holes caused by S. sacchari ranged between 5.3 and 30.3, being dependent on the proof perforations, number of individuals, the area available for feeding and on the survival of the first, second and third instar nymphs that reached the adult stage. The veracity of the hypothesis of the mealybug-rot complex in sugarcane plants is confirmed.
The sugarcane crop Saccharum spp. (Poales: Poaceae) makes Brazil the world's largest producer. Despite of agronomic strategies used, phytosanitary issues such as insect pests and phytopathogenic diseases stand out. The pink sugarcane mealybug Saccharicoccus sacchari (Cockerell, 1895) (Hemiptera: Pseudococcidae) and the red rot fungus Colletotrichum falcatum Went are commonly found in sugarcane crops. In order to understand the performance of the insect pest, related or not to a phytopathogenic agent, it is necessary to study its biological development and the direct and indirect damages that it can cause. This study aimed to evaluate the biological development of S. sacchari under different temperatures, to analyze the biometric and technological characteristics in different phenological stages of sugarcane plants, infested by the mealybug, and to estimate the perforations caused by the pseudococcid through different numbers of the insect and to confirm by Scanning Electron Microscopy (SEM) the mealybug-rot complex. For the analysis of the biological development, gravid females and sugarcane stalks were collected. The stalks were infested with mealybugs, individualized in Petri dishes and kept in two BODs (23 °C ± 2 °C and 28 °C ± 2 °C). The number of eggs, viable and nonviable eggs, incubation time, timing of the last oviposition, nymph hatching, timing of each instar, mortality of nymphs, emergence time and adult longevity were recorded daily. Pseudococcids reproduce by thelytocal parthenogenesis. Under laboratory conditions, the increase in temperature favors the longevity of the insect with three phases of growth. In the study of direct damage, sugarcane plants were infested, at each phenological stage, by gravid mealybugs. The plants were submitted to external biometrics, and in the ripening stage, the technological data were obtained. It was found that the insect infestations at all phenological stages reduce the physical characteristics of the plants, but not the qualitative technological chemistry. To accomplish the last objective, fragmented stems were infested with different numbers of the pseudococcid by geometric progression, and stems infested by the pseudococcid and infected by C. falcatum were collected. The stalks from each treatment were immersed in 1% acid fuchsin solution and the holes were counted. Isolated samples of the pink sugarcane mealybug, the pseudococcid with the mouthparts in plants, the red rot fungus and the mealybug-rot complex were observed under Scanning Electron Microscopy (SEM). It was obtained that the number of holes caused by S. sacchari ranged between 5.3 and 30.3, being dependent on the proof perforations, number of individuals, the area available for feeding and on the survival of the first, second and third instar nymphs that reached the adult stage. The veracity of the hypothesis of the mealybug-rot complex in sugarcane plants is confirmed.
Descrição
Palavras-chave
Podridão vermelha, Tabela de vida, Red rot, Life table, Microscopia eletrônica de varredura, Cana-de-açúcar, Cochonilha