Examinando por Autor "Cappello García, Silvia"

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    Characterization of native isolates of Beauveria bassiana and its pathogenicity to Hypothenemus hampei, en Tabasco, Mexico.
    (Universidad del Valle, 2016-06-30) Gerónimo Torres, José del Carmen; Torres de La Cruz, Magdiel; Pérez de La Cruz, Manuel; Cruz Pérez, Aracely De la; Ortiz García, Carlos Fredy; Cappello García, Silvia
    In order to obtain native isolates of Beauveria bassiana with potential to control Hypothenemus hampei, 12 strains were isolated and characterized according to physiological and pathogenicity variables. Mycelia growth (MG), germination rate and conidial production (CP) in Sabouraud dextrose agar media + 0.1% of yeast extract (SDA+YE), were assessed at 25, 30 and 35 °C. In addition, the conidial production on rice was evaluated at 25 °C. There were differences (P < 0.001) in the MG of the isolates. The favorable temperature for MG ranged between 25 and 30 °C. The time required to 50% of conidial germination (TG50) ranged from 12.6 to 15.9 h, and the TG90 ranged from 16.9 to 61.5 h. The best TG50 and TG90 were obtained at 25 and 30 °C. The optimum temperature for germination, of the majority of the isolates, was 30 °C. There were differences (P < 0.001) on the PdC in the SDA+YE media, and the optimum temperature for the production of conidia was 25 °C. Thus, there were differences (P < 0.001) in the production of conidia in rice. The pathogenic effectiveness of the isolates of B. bassiana on H. hampei was 100%, to the 144 h. Letal time to kill 50% of the population (TL50) ranged from 71.8 to 104 h; as well as, the TL90 ranged from 91.8 to 132.8 h. Native strains BbTcf9, BbTcf5 and BbTcf1 were selected for its evaluation under field conditions.
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    PublicaciónAcceso abierto
    Fungi associated with Hypothenemus hampei (Coleoptera: Curculionidae: Scolytinae) in Tabasco, Mexico.
    (Universidad del Valle, 2019-12-31) Torres de La Cruz, Magdiel; Gerónimo Torres, José del Carmen; Ortiz García, Carlos Fredy; Ayala Escobar, Victoria; Pérez de La Cruz, Manuel; Cappello García, Silvia; Sociedad Colombiana de Entomología - Socolen; Universidad del Valle; Montoya Lerma, James
    In the state of Tabasco, Mexico, the coffee berry borer Hypothenemus hampei, was reported for the first time in 2004. Since then it has become the main insect pest of coffee in this area. The aim of the present study was to document the mycobiota associated to H. hampei adults in coffee plantations of three localities of Tabasco: Teapa, Tacotalpa and Huimanguillo. Coffee berries infested with the coffee berry borer were collected from the field and adults of H. hampei were extracted. The fungi that grew on the Scolytinae cadavers were isolated and identified using taxonomic keys. Two isolates of each morphological species were molecularly identified. A total of 74 isolates was obtained from the cuticle of H. hampei. Of them, 52 presented morphological affinity with Fusarium solani, five with F. oxysporum, five with F. verticillioides, one with Geotrichum candidum and 11 with Beauveria bassiana. The DNA sequences showed similarity with sequences found in GenBank, with homologies of 99 % and 100 %, which coincided with each morphological species. The most abundant species was F. solani (70.2 %), followed by B. bassiana (14.8 %). The species F. verticillioides and F. oxysporum represented each one, at 6.7 %, respectively. The least abundant was G. candidum (1.3 %). The findings of the species F. verticillioides and G. candidum are new reports of micromycetes fungi associated with H. hampei. This study contributes to the knowledge of the diversity of fungi associated with H. hampei.