Search

Background: Spiny bollworm, Earias insulanais a serious cotton pest in Egypt. Besides the economic losses it caused, treatment with chemical insecticides has negative effects on human health and the environment, thus the development of a powerful safe control strategy rather than chemical pesticides is an international goal. Results: Ethyl acetate extract from Aspergillus flavipesAUMC 11390 culture filtrate has an insecticidal activity against E. insulanacausing larval and pupal mortality of 58.33, and 15.59%, respectively, compared with controls, in addition, reduction in adult's emergency and deformation of emerged adults. The impact of fungal extract treatment extended to adult stages by diminishing the male and the female longevity, the number of produced eggs and the hatchability percent. Furthermore, A. flavipesAUMC 11390 ethyl acetate extract caused a strong disturbance on some insect enzymes including amylase, invertase, trehalase, GOT, GPT and acetylcholinesterase, alongside total lipid and total protein. Analysis of ethyl acetate fungal extract revealed the presence of one hydrocarbon 3-Eicosene and four long-chain alcohols namely hexadecanol, 1-hexadecanol, 1-octadecanol, and 1-pentadecanol which are known for their insecticidal activity. Conclusion: A. flavipesAUMC 11390 culture filtrate might represent a promising source for different important bioactive compounds that could be used as a potential biocontrol agent involved in E. insulanamanagement strategies.

Background: Metarhiziumspecies are considered one of the most outstanding powerful biological control agents that have been commercialized as biopesticides against various agricultural pests. Fungal stability with successive in vitro cultivation is a desirable trait for a large-scale production of fungal biopesticide. Main body: The new Egyptian strain Metarhizium anisopliaeAUMC 3262 exhibited auspicious results when compared to Metarhizium brunneumARSEF 4556 and M. brunneumV275 based on the variations of fungal characteristics, and essential quality control parameters (radial growth rate, conidial yield, viability, and virulence) after repeated in vitro subculturing. Changes in morphological characteristics were noted at both AUMC 3262 and ARSEF 4556. Following the 5th subculture, decreased conidial yield was noted, though radial growth remained stable, confirming that there is a non-positive correlation between conidial yield and radial growth rate for these species. In contrast, V275 showed a high morphological stability, conidial yield, and radial growth rate after repeated subculture. The three tested strains manifested high viability up to 100% and displayed the same pattern of Pr1 production. A slight variation was recorded in the median lethal time (LT50) values against the great wax moth, Galleria mellonella(L.), larvae between different subcultures of the tested Metarhiziumstrains. Conclusion: The new Egyptian strain AUMC 3262 showed a high stability with a slight difference in some parameters after the successive subculture compared to both ARSEF4556 and V275.