Survival of Phytophthora cinnamomi and Fusarium verticillioides in commercial potting substrates for ornamental plants

Abstract

Live plants, particularly when accompanied by soil or potting substrates, are considered the main pathway for international spread of plant pathogens. Modern, rapid shipping technologies for international plant trade increase the probability of plant pathogen survival during transport and the subsequent chances of disease outbreaks in new locations. The survival of two model pathogens, an Oomycete, Phytophthora cinnamomi, and a filamentous fungus, Fusarium verticillioides, was studied in two different commercial potting substrates (peat and peat‐free) under glasshouse conditions in the absence of a plant host. Survival rates were analysed at 2, 7, 12 and 17 months after substrate inoculation. Fusarium verticillioides had the longest survival rate, and was still present at 17 months. In contrast, P. cinnamomi survived up to 7 months but was not recovered after 12 or 17 months. There was no significant difference in the number of colony‐forming units (CFUs) of either pathogen in the two substrates, except at 2 months, when higher numbers were recovered from peat substrates.

Oomycetes in rhizosphere soil of ornamental plants from retail nurseries in Southern Sweden

“…The survey provides a first look at the diversity of oomycetes that may move with ornamental plants commonly available in plant trade in Sweden and emphasizes the need to recognize the risks to forest health due to these organisms. Phytophthora species are highly capable of surviving long periods in soil and in potting substrates, especially in the presence of live plant roots (Jung, Vettraino, et al., 2013; Puértolas et al., 2018). In the relatively densely populated area of southern Sweden, planting of ornamental plants in private and public gardens and green areas is common and frequent, and Phytophthora damage has been increasingly observed in deciduous trees growing in the vicinity of such plantings (Cleary et al., 2017).…”

Alleviate environmental concerns with biochar as a container substrate: a review

“…Soil-borne diseases affect potted plants’ marketability and are hard to control ( Katan, 1997 ; Graber et al., 2014 ; Puertolas et al., 2018 ). There are 10~20% of attainable crop yields loss caused by soil-borne diseases and the economic losses in USA are more than $4 billion ( Graber et al., 2014 ).…”

“…There are 10~20% of attainable crop yields loss caused by soil-borne diseases and the economic losses in USA are more than $4 billion ( Graber et al., 2014 ). Soil-borne diseases control becomes more challenging due to trade globalization ( Daughtrey and Benson, 2005 ; Puertolas et al., 2018 ). For instance, Phytophthora ramorum has survived for eight months in root balls and potting substrates of rhododendron plants, affecting the plants marketability worldwide ( Appiah et al, 2004 ; Vercauteren et al., 2013 ).…”

Survival of Phytophthora cryptogea and Phytophthora cactorum in Commercial Potting Substrates for Eucalyptus globulus Plants

“…Vannini et al [12] studied the survival and pathogenicity of Phytophthora × cambivora in a peat-based substrate in the absence of a host and showed an unexpectedly prolonged survival rate over time; propagules maintained an ability to infect chestnut root baits for up to 45 days. The survival of Phytophthora cinnamomi has been investigated in several studies which showed different survival rates, depending on the experimental conditions, of up to 6 years [5,8,13,14]. The potential problems associated with this clear ability of plant pathogens to survive in the absence of a host and retain the ability to reinfect is exacerbated by the extensive movement of soil and substrates associated with trading plants worldwide.…”