Ocorrência e Patogenicidade de Beauveria bassiana à Hypsipyla grandella Coletada em Brasília

Abstract

Um dos principais entraves para o estabelecimento do plantio de mogno (Swietenia macrophylla King) é a ocorrência da Hypsipyla grandella Zeller (Lepidoptera: Pyralidae), que ataca o broto terminal em mudas e árvores novas, formando galerias em seu interior. O trabalho teve como objetivo isolar, identificar e verificar a capacidade patogênica de fungos associados à H. grandella em Brasília, Brasil. Para isso, 200 frutos de mogno atacados pelo inseto foram coletados e analisados. Uma lagarta com sintoma de infecção fúngica foi encontrada. A lagarta sintomática foi colocada em câmara úmida para formação de esporos e então, colônias puras foram obtidas a partir de diluições seriadas e repicagens sucessivas do fungo. Foi feita a sua caracterização molecular e morfológica. O isolado foi identificado como Beauveria bassiana, um entomopatógeno muito utilizado em programas de controle biológico. As colônias puras eram de cor branca e, ao microscópio óptico, apresentavam conídios unicelulares, células conidiogênicas holoblásticas com dentículos conspícuos, caracterizando a espécie. Quanto ao teste de patogenicidade, o isolado se mostrou eficaz, com mortalidade de 70% de ovos e lagartas recém-eclodidas. Este é o primeiro relato de um fungo entomopatogênico encontrado em H. grandella no Distrito Federal. O isolado foi incorporado na Coleção de Fungos de Invertebrados da Embrapa Recursos Genéticos e Biotecnologia. Palavras-chave: entomologia florestal, controle biológico, fungo entomopatogênico. Occurrence and pathogenicity of an isolate of Beauveria bassiana at Hypsipyla grandella collected in Brasilia, Brazil ABSTRACT: One of the main obstacles to the establishment of mahogany plantations is the occurrence of Hypsipyla grandella, which attacks the terminal bud in new seedlings and trees, forming galleries. This study aimed to isolate, identify and verify the pathogenic ability of fungi associated with H. grandella in Brasilia, Brazil. For this, 200 fruit attacked by insects were collected and analyzed. A caterpillar with fungal infection symptom was found. Symptomatic caterpillar was placed in a humid chamber for increased formation of spores and then pure colonies were obtained from serial dilutions and successive subcultures of the fungus. Its molecular, morphological and pathogenic was made. The isolate was identified as Beauveria bassiana, an entomopathogen widely used in biological control programs. Pure colonies were white, and the optical microscope showed unicellular conidia, conidiogenous cells with denticles conspicuous, featuring the species. As for the pathogenicity test, the isolated was effective, with 70% mortality of eggs and newly hatched larvae. This is the first report of an entomopathogenic fungus found in H. grandella the Federal District, Brazil. The isolate was incorporated into the "Coleção de Fungos de Invertebrados" of "Embrapa Recursos Genéticos e Biotecnologia".

Hypsipyla grandella (Lepidoptera: Pyralidae) Boring Khaya ivorensis (Meliaceae) Fruits and Seeds in Brazil: First Report

“…The principal damage occurs when H. grandella larvae feed on meristematic shoot tissues, causing loss of apical dominance, bifurcations, and deformations, and resulting in reduction in the economic value of the trees (Zaché et al 2013;Barradas-Juanz et al 2016a). There are no effective techniques to control this pest, and integrated management has failed to reduce damage to acceptable levels (Barradas-Juanz et al 2016b;Castro et al 2017). The principal strategies to reduce damage by H. grandella larvae, with different success rates, are biological and chemical control, and plant resistance (Perez et al 2010b;Ruiz et al 2016;Castro et al 2017).…”

“…There are no effective techniques to control this pest, and integrated management has failed to reduce damage to acceptable levels (Barradas-Juanz et al 2016b;Castro et al 2017). The principal strategies to reduce damage by H. grandella larvae, with different success rates, are biological and chemical control, and plant resistance (Perez et al 2010b;Ruiz et al 2016;Castro et al 2017).…”

“…The mahogany shoot borer damages native Meliaceae fruits and seeds in Brazil (Pinto et al 2013;Castro et al 2017). These reproductive structures are a good source of protein and minerals for insect nutrition (Pinto et al 2013), and are used to culture H. grandella in the laboratory (Barradas-Juanz et al 2016a;Castro et al 2016).…”