No abstract

Spodoptera frugiperda is a widely distributed insect pest that causes major economic losses in various crops, particularly maize. On the other hand, Beauveria bassiana is an entomopathogenic fungus that establishes symbiotic associations with many plants and contributes to tolerance against biotic and abiotic stresses. In the present work, in laboratory experiments, the effects of the B. bassiana strain GHA, in addition to a native strain (PTG4), delivered via seed treatment in maize seedlings, were evaluated on S. frugiperda growth, development, and mortality. We inoculated maize seeds with 1 × 106B. bassiana blastospores; then these seeds were germinated and grown to seedlings under growth chamber conditions. Third-instar S. frugiperda larvae were allowed to feed on B. bassiana-treated and -untreated (negative control) seedlings until reaching the sixth instar and transferred to an artificial diet until reaching adult stage. Results showed that larvae feeding on B. bassiana strain PTG4-treated plants prolonged their larval stage. Furthermore, feeding on plants treated with B. bassiana strains yielded fewer S. frugiperda male moths compared with feeding with the untreated control plants. Under field conditions, 1 × 106 (first trial) and 1 × 108 (second trial) of B. bassiana (GHA strain) blastospores were used for corn seed inoculation. In the first field trial, there were a higher number of larvae in the negative control plants compared to those in the plants treated with B. bassiana. No larvae were found in negative control and B. bassiana-treated plants in the second field trial. In conclusion, seed treatment with B. bassiana in maize reduced S. frugiperda infestation of maize plants in field trials. S. frugiperda development was also affected in laboratory trials.

Los agentes antimicrobianos son de suma importancia debido a su uso en el tratamiento contra agentesinfecciosos. Muchos de los agentes antimicrobianos conocidos y nuevas moléculas recién descubiertas son metabolitos secundarios de microrganismos bacterianos y fúngicos, así como de diversas plantas. Los metabolitos secundarios son compuestos producidos por un microorganismo o una planta y no son requeridos para su desarrollo, crecimiento, o reproducción. Estos compuestos son sometidos a investigación con la finalidad de utilizarse clínicamente tras demostrar su eficacia y seguridad, lo que brinda la oportunidad de ampliar las opciones terapéuticas disponibles hoy en día. Sin embargo, tenemos una carrera a contrarreloj entre el desarrollo de nuevos agentes antimicrobianos y el surgimiento de microorganismos farmacorresistentes. En este artículo de divulgación, damos a conocer algunos de los metabolitos secundarios empleados cotidianamente como agentes antimicrobianos y su origen, así como nuevas moléculas bajo estudio con potencial uso terapéutico.

Spodoptera frugiperda is a widely distributed insect pest that causes major economic losses in various crops, particularly maize. On the other hand, Beauveria bassiana is an entomopathogenic fungus that establishes symbiotic associations with many plants and contributes to tolerance against biotic and abiotic stresses. In the present work, under field conditions, 1x106 (first trial) and 1x10⁸ (second trial) of B. bassiana (GHA strain) blastospores were used for corn’s seed inoculation. In the first field trial, a higher number of larvae were present in the negative control plants in comparison with those in B. bassiana-treated plants. No larvae were found in negative control and B. bassiana-treated plants in the second field trial. In further laboratory experiments, the effects of the B. bassiana strains GHA, in addition to a native strain (PTG4) also delivered via seed treatment in maize seedlings, on S. frugiperda growth, development, and mortality were evaluated. 1x10⁶ B. bassiana blastospores were used to inoculate maize seeds, which were germinated and grown to seedlings under growth chamber conditions. Third-instar S. frugiperda larvae were allowed to feed on B. bassiana-treated and -untreated (negative control) seedlings until reaching 6th instar and transferred to artificial diet until reaching adult stage. Results showed that larvae feeding on B. bassiana strain PTG4 prolonged their larval stage. Furthermore, feeding with plants treated with B. bassiana strains yielded fewer S. frugiperda male moths and the female moths emerged with altered wings, compared with the untreated control. In conclusion, seed treatment with B. bassiana in maize reduced S. frugiperda infestation of maize plants in field trials. Besides S. frugiperda development was affected in laboratory trials.