Poster – Unity is strength: biological and mechanical control as a weapon against Tree on heaven

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Abstract

Tree of heaven (Toh, Ailanthus altissima) is a tree native to China that is considered a serious weed species worldwide. Due to its extensive root system and the ability to aggressively sucker and resprout, mechanical control methods, such as felling large trees or removing a strip of bark to prevent nutrients from reaching the roots, are largely ineffective. Aculus taihangensis is a Chinese eriophyid mite highly specific to Toh and present in Europe and North America. Due to its ability to reduce the fitness and biomass of new sprouts and seedlings, we explore the potential of A. taihangensis to act where mechanical control methods fail. Specifically, Toh trees in Lyon, central France, were cut down, and the subsequent sprouts were inoculated with mites in April and then monitored until September. Additionally, mechanical debarking was applied to larger trees. The success of the mite inoculation was verified, as were the presence of mite symptoms and plant survival. Finally, the size and weight of the inoculated and uninoculated resprouts were compared. The results confirmed the impact of the mite on Toh resprouts, characterised by reduced growth and premature leaf fall. These preliminary results are very promising and support the integration of A. taihangensis with mechanical control methods for a multifaceted approach against Toh.

Keywords 

Aculus taihangensis 

Tree of heaven 

Integrated weed biocontrol 

biological control 

mechanical control 

Highlights 

Aculus taihangensis and mechanical control are effective in working together against Toh 

Aculus taihangensis is an effective biological control agent for Toh resprouts 

Aculus taihangensis can be successfully released to support the management of Toh