Entomopathogenic fungi: an alternative for the biological control of aphids (Phorodon cannabis) in cannabis (Cannabis sativa) plants

The rapid expansion of the cannabis industry in Canada post-legalization has heightened the prevalence of pests, particularly the cannabis aphid Phorodon cannabis,which poses significant threats to crop health. This study investigates the immediate effects of P. cannabis on Cannabis sativa plants and explores biological control strategies utilizing entomopathogenic fungi. The research aims to test the antagonistic activity of various fungal isolates against aphids, analyze the immune responses of cannabis plants to infection, assess the impact on metabolite production and yield, and develop effective application strategies for these biocontrol agents. Fungal isolates of Beauveria and Metarhizium were isolated and characterized. Infection tests on aphids demonstrated the potential of these fungi to control aphid populations without the environmental drawbacks associated with chemical insecticides. Bioassays revealed that both fungi achieved 100% aphid mortality at high conidial concentrations (1×10⁷ conidia/mL), with Beauveria bassiana demonstrating faster efficacy. In greenhouse trials, Beauveria bassiana maintained aphid populations below 20 aphids throughout the experiment across all varieties and maintaining cannabis growth parameters comparable to the chemical insecticide. Untreated aphid infections substantially reduced plant height and biomass across three cannabis varieties tested, reaching heights of 40-48 cm and under 4 g of dry biomass. Cannabinoid and terpene analyses revealed that Beauveria bassiana-treated plants exhibited higher concentrations of key metabolites, including THCa, CBDa, and total terpenes, compared to chemically treated plants. The findings highlight Beauveria bassiana as an eco-friendly alternative for pest management that not only effectively controls aphids but also supports the biochemical quality of cannabis plants. Findings suggest that entomopathogenic microorganisms can significantly mitigate the impact of P. cannabis on cannabis seedlings, offering a sustainable alternative to chemical controls. This research contributes to the understanding aphid interactions with cannabis plants and promotes eco-friendly pest management practices within the burgeoning cannabis industry.

Authors

• Lopez Restrepo, Daniel A>
• University of Lethbridge. Faculty of Arts and Science

• Entomopathogenic fungi
• Cannabis
• Beauveria
• Biocontrol
• Aphids
• Pest management

Identifier

hdl:10133/7024

OAI identifier oai:identifier

oai:opus.uleth.ca:10133/7024