How long can Phytophthora ramorum survive in soil moved from an infested area?

Survival of P. ramorum (SOD pathogen) in dead hosts or non-plant substrates is extremely variable and strongly affected by climatic factors. Although a comprehensive study on this topic has not conducted, extrapolating from several studies we can say the following:

Soil becomes more infectious from late winter to early summer in the presence of rainfall, so any movement of soil away from a SOD-infested area from January to July could transport viable P. ramorum.

Keep the following in mind:

  • The larger the volume of soil moved, the greater the risk.
  • In organic rich soils (e.g. top layers of forest soils), pathogen survival is less than 18 months.
  • If P. ramorum is present in green waste incorporated in the soil, survival can be much longer (2 years or more).
  • In inert soils (e.g. potting mix), the pathogen can survive multiple years.¬† However, for all soils, areas with less temperate climates (cold winters, hot summers) may hasten loss of pathogen viability.

From a practical perspective, if infested forest soil is picked up on tires or shoes from late winter to early summer, the pathogen will likely remain viable for about 1 year, in the absence of incorporated green waste. If soil is picked up from late summer to early fall, survival duration is much less, possibly in the order of a few months.

Please log in to rate this.
1 person found this helpful.


Category: Sudden Oak Death
Tags: , , , , , , , , ,

← How long can Phytophthora ramorum survive in soil moved from an infested area?
How long can Phytophthora ramorum survive in soil moved from an infested area?