Evaluation of isolates of entomopathogenic fungi in the genera Metarhizium, Beauveria, and Isaria, and their virulence to Thaumastocoris peregrinus (Hemiptera: Thaumastocoridae)

Authors

  • Tárcio Souza Santos University Tiradentes, Industrial Biotechnology Program, Aracaju, Sergipe, 49032-490, Brazil;
  • Aline Corrêa de Freitas University Tiradentes, Industrial Biotechnology Program, Aracaju, Sergipe, 49032-490, Brazil; E
  • Júlio César Melo Poderoso Federal University of Sergipe, Department of Agronomy, São Cristovão, Sergipe, 49100-000, Brazil;
  • Maria Lucila Hernandez-Macedo University Tiradentes, Industrial Biotechnology Program, Aracaju, Sergipe, 49032-490, Brazil;
  • Genésio Tâmara Ribeiro Federal University of Sergipe, Department of Agronomy, São Cristovão, Sergipe, 49100-000, Brazil;
  • Luiz Pereira da Costa University Tiradentes, Industrial Biotechnology Program, Aracaju, Sergipe, 49032-490, Brazil;
  • Marcelo da Costa Mendonça University Tiradentes, Industrial Biotechnology Program, Aracaju, Sergipe, 49032-490, Brazil;

Keywords:

eucalyptus, eucalyptus pests, biological control

Abstract

Thaumastocoris peregrinus Carpintero and Dellapé, or bronze bug (Hemiptera: Thaumastocoridae), is a pest found in eucalyptus plantations worldwide. Use of entomopathogenic fungi has emerged recently as an alternative means of control for T. peregrinus. Here we report laboratory experiments conducted to select isolates of entomopathogenic fungi for use to control this pest. Seven isolates of Beauveria bassiana (Bals.-Criv.) Vuill. (Hypocreales: Cordycipitaceae), 3 of Metarhizium anisopliae (Metschn.) Sorokīn (Hypocreales: Clavicipitaceae), 2 of Metarhizium robertsii J.F. Bisch., S.A. Rehner & Humber (Hypocreales: Clavicipitaceae), and 2 of Isaria fumosorosea Wize (Hypocreales: Cordycipitaceae) at a concentration of 1 × 108 conidia per mL were assessed for their virulence to adults of T. peregrinus. In vitro growth and sporulation of the isolates also were evaluated through the analysis of colony development and conidia production in PDA culture medium, at 26 ± 1 °C, 70% RH, and a 12:12 h (L:D) photoperiod. All tested isolates were found to be pathogenic to T. peregrinus. The isolates Bb3, Bb4, Bb7, Ma1, Ma2, Mr2, and If1 exhibited significant virulence to the insect. The greatest growth (longest mean diam of colony) was for the isolate Ma2, whereas the highest sporulation rates were observed in the isolates If2 and Ma2. This study demonstrated that isolates of Beauveria, Metarhizium, and Isaria can cause infection in T. peregrinus. The Ma2 isolate of Metarhizium stood out for its pathogenic effect on the adult insect, as well as for its capacity to grow rapidly and produce large numbers of conidia on an artificial medium, indicating its potential for use as a microbial control agent for T. peregrinus, and its suitability for mass production.

 

Resumen

Thaumastocoris peregrinus Carpintero and Dellapé, ou percevejo-bronzeado do eucalipto (Hemiptera: Thaumastocoridae), é uma praga nas plantações de eucalipto em todo o mundo. O uso de fungos entomopatogênicos emergiu recentemente como meio alternativo de controle de T. peregrinus. Aqui nós relatamos experimentos de laboratório feitos para selecionar isolados de fungos entomopatogênicos para uso contra esta praga. Sete isolados de Beauveria bassiana (Bals.-Criv.) Vuill. (Hypocreales: Cordycipitaceae), 3 de Metarhizium anisopliae (Metschn.) Sorokīn (Hypocreales: Clavicipitaceae), 2 de Metarhizium robertsii J.F. Bisch., S.A. Rehner & Humber (Hypocreales: Clavicipitaceae), e 2 de Isaria fumosorosea Wize (Hypocreales: Cordycipitaceae) na concentração de 1 × 108 conídios por mL foram avaliados em relação a sua virulência contra adultos de T. peregrinus. O crescimento e a esporulação in vitro dos isolados também foram avaliados, através da análise do desenvolvimento de colônias e produção de conídios em meio de cultura de BDA, a 26 ± 1 °C, 70% de UR, e fotoperíodo de 12:12 h (L:D). Todos os isolados testados foram patogênicos para T. peregrinus. Os isolados Bb3, Bb4, Bb7, Ma1, Ma2, Mr2, e If1 exibiram significativa virulência ao inseto. O maior crescimento (maior diâmetro médio de colônia) foi para o isolado Ma2, enquanto as maiores taxas de esporulação foram observadas nos isolados If2 e Ma2. Este estudo demonstrou que isolados de Beauveria, Metarhizium e Isaria podem causar infecção em T. peregrinus. O isolado Ma2 de Metarhizium destacou-se pelo seu efeito patogênico no inseto adulto, bem como por sua capacidade de crescer rapidamente e produzir um grande número de conídios em meio artificial, indicando seu potencial de uso como agente de controle microbiano contra T. peregrinus e sua adequação para produção em massa.

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Published

2019-02-04

Issue

Vol. 101, No. 4 (December 2018)

Section

Research Papers

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