Insecticidal activity influence of 20-Hydroxyecdysone on the pathogenicity of Isaria fumosorosea against Plutella xylostella

The bioactivity of the entomopathogenic fungus, Isaria fumosorosea, and the plant secondary chemical, 20-Hydroxyecdysone, against Plutella xylostella were tested. 20-Hydroxyecdysone gave an apparent increase in adjusted larval mortality in a dose-dependent manner, whereas no influence of 20-Hydroxyecdysone was observed on conidial germination, mycelial growth and conidial production of I. fumosorosea. Furthermore, the synergism between 20-Hydroxyecdysone and I. fumosorosea was studied under laboratory and field cage conditions. Percent cumulated adjusted mortality of P. xylostella after the application of different concentrations of 20-Hydroxyecdysone and I. fumosorosea showed that the mortalities were directly related to the concentration of each component in the mixtures and their cumulative effect was evident for an extended period.

The bioactivity of the entomopathogenic fungus, Isaria fumosorosea, and the plant secondary chemical, 20-Hydroxyecdysone, against Plutella xylostella were tested. 20-Hydroxyecdysone gave an apparent increase in adjusted larval mortality in a dose-dependent manner, whereas no influence of 20-Hydroxyecdysone was observed on conidial germination, mycelial growth and conidial production of I. fumosorosea. Furthermore, the synergism between 20-Hydroxyecdysone and I. fumosorosea was studied under laboratory and field cage conditions. Percent cumulated adjusted mortality of P. xylostella after the application of different concentrations of 20-Hydroxyecdysone and I. fumosorosea showed that the mortalities were directly related to the concentration of each component in the mixtures and their cumulative effect was evident for an extended period.Figure optionsDownload as PowerPoint slideResearch highlights
► This study explains the effect of 20-Hydroxyecdysone on the susceptibility of I. fumosorosea to P. xylostella.
► We have also explained the compatibility between 20-Hydroxyecdysone and I. fumosorosea for P. xylostella management.
► Our results are encouraging to use 20-Hydroxyecdysone and I. fumosorosea in the field and controlled environments like glasshouses or greenhouses, because they are synergistic since the conidial germination of the fungus was not affected by different concentrations of 20-Hydroxyecdysone.