A review of potential biological controls for Ailanthus altissima

Abstract

Ailanthus altissima (Mill.) Swingle (Sapindales: Simaroubaceae) (tree-of-heaven) is an invasive tree species first introduced to the United States in 1784. With high rates of sexual reproduction, rapid growth, and prolific vegetative sprouting, A. altissima is an aggressive competitor that reduces native plant diversity and is difficult to manage beyond small-scale infestations. In the United States, the issues associated with Ailanthus management were compounded by the 2014 arrival of Lycorma delicatula (spotted lanternfly). Lycorma delicatula coevolved with A. altissima, its primary host, in eastern Asia. Suppression of A. altissima is recommended as an important strategy to slow the spread of L. delicatula. Due to the inadequacy of traditional control methods to manage A. altissima, biological controls are desired. Several potential biological control agents have been proposed for A. altissima. This review discusses current research on several promising candidates, specifically a native fungus, Verticillium nonalfalfae Inderb. et al. (Hypocreales: Plectosphaerellaceae); a trunk-boring beetle, Eucryptorrhynchus brandti (Harold) (Coleoptera: Curculionidae: Cryptorrhynchinae); and an eriophyid mite, Aculops ailanthi (Lin-Fuping, Jin-Changle & Kuang-Haiya) (Arachnida: Eriphyidae). A list of other possible biological control agents is also provided. We discuss unanswered questions for each species, the limits of biological controls in this system, and call for further research on integrated pest management practices for managing A. altissima.