Understanding and Managing Sudden Oak Death in California

SIDEBAR 1-3—Host Susceptibility Versus Spore Production

Hosts that develop severe foliar symptoms when infected by P. ramorum may not support production of significant numbers of spores. Among native species, Pacific madrone is an example that shows this pattern. In contrast, some species that are not overly susceptible to P. ramorum support production of high numbers of spores. Known relationships between host susceptibility and spore production are shown in Table 1-3.

Table 1-3—Comparison between susceptibility to Phytophthora ramorum foliar infection and P. ramorum spore production on various hosts

Amount of   Susceptibility  
sporulation High Moderate Low to resistant
High Ceratonia siliqua Castanea sativa1 Acer pseudoplatanus
  Larix kaempferi1,2 Cistus salvifolius Hedera helix
  Rhamnus alaternus Lonicera implexa Lonicera periclymenum
  Rhododendron catawbiense1 Michelia doltsopa1 Quercus petraea
  Syringa vulgaris1 Pistacia lentiscus Quercus robur
  Umbellularia californica1 Pistacia terebinthus Rosa canina
    Quercus ilex1 Rubus fructicosus
    Quercus cerris1  
    Rosa sempervirens  
    Vaccinium myrtillus  
       
Moderate Arbutus unedo1 Aesculus hippocastanum Viburnum opulus1
  Camellia japonica1 Corylus avellana  
  Fraxinus excelsior1 Malus sylvestris  
  Magnolia sp. 1 Ulmus glabra  
  Pieris japonica1 Ulmus procera  
  Quercus ilex1    
  Rhododendron catawbiense1    
  Rhododendron ponticum1    
  Viburnum tinus1    
       
Low Arctostaphylos uva-ursi   Calluna vulgaris
  Kalmia latifolia   Taxus bacatta1
  Sambucus nigra   Vaccinium x intermedium
      Vaccinium vitis-idaea
None     Empetrum nigrum
      Pinus halepensis
      Quercus pyrenaica

Source: Moralejo and others 2007

1Found naturally infected in the United Kingdom.

2Added to list based on Webber and others 2010.