Characterization of Native Isolates of Metarhizium Anisopliae And Its Pathogenicity To Aeneolamia Postica In Tabasco,Mexico

Abstract

In order to obtain native isolates of Metarhizium anisopliae with potential to control Aeneolamia postica, four polysporic strains, 12 monosporic and a commercial strain were characterized according to physiological and pathogenic variables. The mycelial development, germination rate and conidia production were considered physiological variables; the first two were evaluated at three temperatures: 25, 30 and 35 °C. The best temperature for mycelial growth of native strains ranged between 25 and 30 °C. The time required to 50% of conidial germination (TG₅₀) ranged from 6.3 to 13.2 h, where the lowest and highest TG₅₀ were 30 °C and 35 °C, respectively. Native strains were less sensitive than the commercial strain at all temperatures tested. Regarding to conidial production, polysporic strains outperformed to the monosporic isolates. The pathogenic effectiveness of M. anisopliae to A. postica ranged from 31.9 to 53.6%. The physiological and pathogenic characteristics to select the best biocontrol strains were higher in monosporic strains. The strains with greatest potential for biocontrol of A. postica, were the monosporic MaA3 (1), MaA3 (2), MaA2 (7), MaA2 (1), and the polysporic MaA4 strain.