Urban environments provide opportunities for early detections of Phytophthora invasions

Abstract

Globalization has increased the frequency of inadvertent introductions of plant pathogens. Many catastrophic invasions of both natural and agricultural systems have been initiated through anthropogenic dissemination pathways. Phytophthora species are a group of invasive plant pathogens causing many of the most important plant disease epidemics. A review of Phytophthora species descriptions published following the publication of the first DNA-based Phytophthora phylogeny was conducted to highlight patterns of recent introductions and to provide insights for early pathogen detection initiatives. Seventy-two publications from 2001-2016 describing 98 Phytophthora species were evaluated. Of the 91 species with geographic location isolation data, 22% of species were described from type specimens isolated from urban environments, 33% from agricultural environments and 45% from natural environments. Within the urban environment, ornamental plant trading nurseries were the most important sources. Specifically, for Phytophthora ramorum, a species causing multiple epidemics globally, the largest proportion of first report publications were from urban environments, including nurseries. Nearly a quarter of the species descriptions were based on isolates from the urban environment, including ornamental nurseries, and the majority of the first reports for P. ramorum were also from this environment. We therefore suggest that detection programs for invasive plant pathogens within the urban environment would be valuable. In this regard, specialized monitoring and citizen science projects that target urban areas where live plant-trading industries are concentrated would be particularly effective to both promote early detection and to facilitate a rapid response to new species invasions.

Predictors of Phytophthora diversity and community composition in natural areas across diverse Australian ecoregions

“…As such, the pathway of introduction into the natural ecosystem of Phytophthora species appears to be through food production (Santini et al 2018), with the species most likely to invade natural ecosystems being those that can cause disease in perennial plants. The urban and periurban environment is also seen as a main pathway for the introduction of new pathogens into natural ecosystems (Hulbert et al 2017) and plant production nurseries play a major role in this pathway as had been demonstrated for the introduction of new Phytophthora species into natural ecosystems in Europe (Jung et al 2015). Our sites were all in natural ecosystems, and yet we were just as likely to recover an introduced as native species.…”

“…All records of P. citricola isolated from agriculture and urban settings in Australia have been reclassified as P. multivora (Burgess et al 2009, Barber et al 2013, Dunstan et al 2016). The urban and periurban environment is also seen as a main pathway for the introduction of new pathogens into natural ecosystems (Hulbert et al 2017) and plant production nurseries play a major role in this pathway as had been demonstrated for the introduction of new Phytophthora species into natural ecosystems in Europe (Jung et al 2015). As such, the pathway of introduction into the natural ecosystem of Phytophthora species appears to be through food production (Santini et al 2018), with the species most likely to invade natural ecosystems being those that can cause disease in perennial plants.…”

Non-native species in urban environments: patterns, processes, impacts and challenges

“…Aronson et al (2017) highlight the importance of rivers as corridors in urban systems and the fact that their functioning as networks is threatened by plant invasions. Hulbert et al (2017) emphasize a special management need for plant pathogens in urban areas. Urban areas in most regions are a complex mix of public and private land.…”

The role of citizen science in addressing grand challenges in food and agriculture research

“…Citizen science is already helping to document novel pathogens and pests. For example, citizens are helping provide first reports of pathogens, such as in the case of Sudden Oak Death that was first reported by a concerned citizen [8] and helping to document the movement of pests and pathogens, for example, through projects like Cape Citizen Science (citsci.co.za), where citizen scientists in urban areas monitor plant pathogens in South Africa. These efforts help to improve model predictions of future spread [9,10].…”