Conundrums of a complex vector for invasive species control: a detailed examination of the horticultural industry

Abstract

Historically the horticultural industry has transformed the US landscape through intentional cultivar introductions and unintentional introductions of weeds, insects and plant diseases. While it has been demonstrated that the horticultural industry, in particular the ornamental subsector, is an important vector for the introduction and dispersal of invasive species, known invasive plants continue to be sold while new cultivars are introduced at an ever increasing rate. This study examines the horticultural trade as a vector for invasive species, its agents, and characterizes the complexity of the distribution channel. Numerous factors have contributed to the recent expansion in marketed cultivars, including technological, industry growth, and marketing developments. The result has been an increased and sophisticated consumer demand with a corresponding aggressive scouring of the planet for new crops, many of which are introduced into the market without sufficient testing for invasive tendencies. Traditional approaches to invasive horticultural crop control (regulation, self-regulation), which target players in the distribution channel before and/or after cultivar release, have had limited effectiveness and buy-in because these approaches do not address the industry's complexities and economic incentives. Involvement and education of consumers may provide better oversight outcomes by addressing the moral hazard problem while acknowledging the key characteristics of the industry.

Laurel Wilt in Natural and Agricultural Ecosystems: Understanding the Drivers and Scales of Complex Pathosystems

“…For example, residential trees played a significant role in epidemics of citrus canker in Florida and plum pox in Canada [154,155]. Residential trees are also associated with the regional spread of pathogens via the nursery trade, as infected asymptomatic plants can be sold and distributed through this network [156,157]. In this case, the short latent period of laurel wilt on susceptible hosts may be advantageous, as asymptomatic infection of these species would probably play a negligible role in spreading the disease.…”

Tree disease and pest epidemics in the Anthropocene: A review of the drivers, impacts and policy responses in the UK

“…Following a period of rapid globalisation, these roles and distinctions between businesses in the increasingly complex supply chain are now less clear. Specialisation has increased efficiency and the potential to distribute ever-greater volumes and varieties of plant material and plants for planting more rapidly through (often unregulated) industry channels (Drew et al, 2010). Given extensive horizontal and vertical integration, the horticultural industry can be seen as a supply chain with multiple layers of firms, each with a unique set of functions.…”

A trait‐based ecology of the Los Angeles urban forest

“…We were unable to satisfactorily quantify these types of traits in this initial classification, but it may be possible to do so with other methods or survey instruments. In addition, there are important filters of the species that are commercially available to local homeowners via the horticultural industry (DehnenSchmutz et al 2007, Drew et al 2010, Pincetl et al 2013. Pincetl et al (2013) quantified the tree species available for purchase in Los Angeles nurseries throughout the 20th century and found that there has been an increasing palette of commercially available tree species, currently over 500, sold by local nurseries in response to economic pressure.…”