Screening of Verticillium lecanii isolates for controlling of Cinara atlantica

O objetivo deste trabalho foi avaliar a patogenicidade de isolados de Verticillium lecanii, sobre Cinara atlantica, e estimar a CL50 do melhor isolado. No teste de seleção, utilizaram-se mudas de pinus com ninfas do pulgão, 20 isolados do fungo e um controle, num total de 21 tratamentos e dez repetições. Na CL50 do isolado CG 904, utilizaram-se seis concentrações, com dez repetições. VL 6, CG 902 e VL 2 apresentaram os mais altos índices de mortalidade, 72,22%, 67,34% e 67,31%, respectivamente. A testemunha apresentou mortalidade de 15,6%. Nos bioensaios de CL50, a concentração de 108 conídios mL-1, do isolado CG 904, causou mortalidade de 100%, CL50 de 2x105 conídios mL-1 e TL50 de 4,4 dias.The aim of this study was to evaluate the pathogenicity of Verticillium lecanii isolates against Cinara atlantica, and the LC50 of the best strain. For selection tests, nymphs of C. atlantica were placed on individual pine seedling with 20 isolates and one control, in a total of 21 treatments and ten replicates. For the LC50 estimation it was used the CG 904 strain with six concentrations and ten replicates. VL 6, CG 902 and VL 2 produced the highest mortality, of 72.22%, 67.34% and 67.31%, respectively. The control plot showed mortality of 15.6%. The LC50 of the CG 904 strain indicated mortality of 100% at the concentration of 108 conidia mL-1; LC50, 2x105 conidia mL-1; and LT50, 4.4 days

Entomopathogenic fungi in the control of Hedypathes betulinus and evaluation of persistence

Hedypathes betulinus (KLUG, 1825) (Coleoptera: Cerambycidae) é a principal praga da cultura da erva-mate. Para o seu controle, avaliou-se em laboratório e campo a utilização de fungos entomopatogênicos. Em laboratório, foi avaliada a infectividade de isolados dos fungos Beauveria bassiana (Bals.) Vuillemin, 1912; B. brongniartii (Sacc.) Petch, 1926; Metarhizium anisopliae (Metsch.) Sorokin, 1883, e Paecilomyces (=Isaria) sp. Bainier, 1907, em adultos de H. betulinus. Os insetos foram imersos nas suspensões fúngicas na concentração de 107 conídios/mL. Após a aplicação, eles foram mantidos em laboratório para registro da mortalidade. Verificou-se que B. bassiana (CG 716) foi o mais infectivo, com 100% de mortalidade. Foi estimada a CL50 do isolado CG 716 de B. bassiana com cinco concentrações, variando de l05 a l09 conídios/mL, mais a testemunha. A CL50 estimada foi de 2,0x106 conídios/mL, variando de 6x105 a 5x106 conídios/mL. Foi avaliada a persistência do isolado CG 716 de B. bassiana formulado à base de óleo emulsionável em campo, verificando-se alta mortalidade nas primeiras três semanas após a aplicação do fungo, variando de 95 a 78%, decaindo para 65 a 47%, um e dois meses após a aplicação, respectivamente.Palavras-chave: Controle biológico; broca-da-erva-mate; CL50. AbstractEntomopathogenic fungi in the control of Hedypathes betulinus and evaluation of persistence. Hedypathes betulinus (KLUG, 1825) (Coleoptera: Cerambycidae) is the main pest of “erva-mate” (Ilex paraguariensis) culture. Focusing its control, it was evaluated in laboratory and field the entomopathogenic fungi using. In laboratory, it was evaluated the infectiveness of the strains of the following fungi: Beauveria bassiana (Bals.)  Vuillemin, B. brongniartii (Sacc.) Petch, Metarhizium anisopliae (Metsch.), Sorokin and Paecilomyces (= Isaria) sp. Bainier, in adults specimen of H. betulinus. The insects were immersed in a conidial suspension at a concentration of 107 conidia mL-1. After the application the insects had been kept at laboratory for mortality register. It was verified that B. bassiana (CG 716) was more infective, reaching to 100% of mortality. It estimated LC50 of isolated CG 716 of B. bassiana with five concentrations and a variation of l05 to l09 conidia mL-1, along the control plot. The estimated LC50 was 2,0 x 106 conidia mL-1, ranging from 6 x 105 to 5 x 106 conidia mL-1. The persistence of strain CG 716 of B. bassiana - formulate oil was evaluated in field, producing the highest mortality, at the first three weeks after the application of the fungus, with a variance of 95 to 78 %, with a decreasing of 65 to 47% , along one and two months after the application , respectively.Keywords: Biological control; erva-mate pest; LC50,.Hedypathes betulinus (KLUG, 1825) (Coleoptera: Cerambycidae) is the main pest of “erva-mate” (Ilex paraguariensis) culture. Focusing its control, it was evaluated in laboratory and field the entomopathogenic fungi using. In laboratory, it was evaluated the infectiveness of the strains of the following fungi: Beauveria bassiana (Bals.)  Vuillemin, B. brongniartii (Sacc.) Petch, Metarhizium anisopliae (Metsch.), Sorokin and Paecilomyces (= Isaria) sp. Bainier, in adults specimen of H. betulinus. The insects were immersed in a conidial suspension at a concentration of 107 conidia mL-1. After the application the insects had been kept at laboratory for mortality register. It was verified that B. bassiana (CG 716) was more infective, reaching to 100% of mortality. It estimated LC50 of isolated CG 716 of B. bassiana with five concentrations and a variation of l05 to l09 conidia mL-1, along the control plot. The estimated LC50 was 2,0 x 106 conidia mL-1, ranging from 6 x 105 to 5 x 106 conidia mL-1. The persistence of strain CG 716 of B. bassiana - formulate oil was evaluated in field, producing the highest mortality, at the first three weeks after the application of the fungus, with a variance of 95 to 78 %, with a decreasing of 65 to 47% , along one and two months after the application , respectively