Insecticidal Action of Local Isolates of Entomopathogenic Fungi Against Bactrocera oleae Pupae

Summary

Olive farmers in Mediterranean countries struggle with the olive fruit fly, which damages olives and reduces oil production. Researchers tested special fungi that naturally infect and kill insects to see if they could control this pest at the soil stage when fly pupae are developing underground. Several fungal species, especially Beauveria bassiana, were effective at reducing survival of emerged adult flies by about 40% compared to untreated flies. This offers a promising natural alternative to chemical pesticides that can harm olive oil quality and lose effectiveness over time.

Background

Bactrocera oleae (olive fruit fly) is a major pest affecting olive cultivation in the Mediterranean region, causing significant economic damage. The extensive use of chemical insecticides has led to pesticide resistance and environmental concerns. Entomopathogenic fungi (EPFs) offer a promising biological control alternative.

Objective

To evaluate the insecticidal efficacy of local isolates of entomopathogenic fungi against Bactrocera oleae pupae under both soil and non-soil conditions. The study aimed to assess whether EPFs can effectively control the olive fruit fly at the pupal stage when it naturally inhabits soil.

Results

Beauveria bassiana isolate 13.20 showed the lowest adult survival time (5.56 ± 0.42 days in soil; 6.76 ± 0.46 days non-soil) compared to control (9.83 ± 0.83 days soil; 9.90 ± 0.72 days non-soil). Significant variation in virulence was detected among isolates, with several isolates achieving 100% mycelium coverage on dead pupae. The presence of mycelium confirmed pathogen-related mortality.

Conclusion

Local isolates of entomopathogenic fungi, particularly B. bassiana strains, demonstrated significant ability to reduce B. oleae survival at the pupal stage in soil environments. These findings support the potential use of EPFs as an ecologically friendly alternative to chemical insecticides for olive fruit fly control in Mediterranean regions, though field trials are needed to validate laboratory results.
Scroll to Top