Attraction, Oviposition and Larval Survival of the Fungus Gnat, Lycoriella ingenua, on Fungal Species Isolated from Adults, Larvae, and Mushroom Compost

Summary

This research investigated what attracts fungus gnats to mushroom growing facilities and what causes them to lay eggs. The study found that different fungi present in mushroom compost attract female flies and influence where they lay their eggs. This knowledge could help develop better ways to control these destructive pests in mushroom farms. Impacts on everyday life: • Could lead to better pest control methods for mushroom farmers • May help reduce crop losses and keep mushroom prices stable • Provides insight into managing agricultural pests more sustainably • Could reduce the need for chemical pesticides in mushroom production • Demonstrates the complex relationships between insects and fungi in agriculture

Background

The fungus gnat Lycoriella ingenua is a severe pest of cultivated white button mushrooms (Agaricus bisporus) in the United States. Previous research showed females are attracted to mushroom compost and the parasitic green mold Trichoderma aggressivum, but not to mushrooms themselves. Understanding what attracts these pests is important for developing control methods.

Objective

To identify fungal species in mushroom compost that attract female L. ingenua flies and induce oviposition by isolating fungi from adult males and females, third instar larvae, and mushroom compost itself. The study aimed to find fungal species that might be more attractive than T. aggressivum for potential use in pest monitoring and control.

Results

Females were most attracted to T. aggressivum, Penicillium citrinum (isolated from adult females), and Scatylidium thermophilium (from compost). The highest oviposition occurred on T. aggressivum, Aspergillus flavus (from larval frass), Aspergillus fumigatus (from adult females), and P. citrinum. Larval survival to adulthood was only successful on P. citrinum (60%), Chaetomium sp. (73%), and S. thermophilum (70%).

Conclusion

Different fungal species in mushroom compost appear to work together to influence L. ingenua behavior, with some species attracting females and others inducing oviposition. T. aggressivum remains the most behaviorally active fungus. The findings suggest potential for developing synthetic lures using fungal volatiles for monitoring and controlling female flies during the critical first 14 days of mushroom crop development.
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