About Reproductive Hosts
Reproductive hosts are plant species that are capable of 1) supporting beetle reproduction and 2) growing the fungi that cause Fusarium dieback. Source: Eskalen, A. et al. 2013-2018 https://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-11-12-1026-RE
ISHB or Fusarium dieback hosts may be trees identified as showing signs of beetle or beetle and fungal attack in the field, or trees specifically challenged with beetles and/or fungal pathogens in controlled experiments. They are determined to be reproductive hosts when all life stages of the beetle species are found inhabiting them. Many more trees may host beetle attack than those that are confirmed to be reproductive hosts.
The UC research team does NOT intend this list to be used as a "do not plant" list. In some cases, ongoing research is investigating cases where even highly susceptible host species recover from attack. The choice of where, and under what conditions, to plant any tree species should include factors such as the uses, whether ecosystem or social, of the tree, and the surrounding conditions, including threats a weakened tree could pose, and whether the site under consideration is in or near a known infestation area.
* indicates California native
See signs of ISHB infestation in most of the species listed below.
Host List
Susceptible to ISHB-FD (may cause tree death)
- Acer buergerianum - Trident maple
- Acer macrophyllum - Big leaf maple*
- Acer negundo - Box elder*
- Parkinsonia aculeata - Palo verde
- Platanus racemosa - California sycamore*
- Platanus x hispanica - London plane
- Populus fremontii - Fremont cottonwood*
- Populus nigra - Black poplar*
- Populus trichocarpa - Black cottonwood*
- Quercus lobata - Valley oak*
- Quercus robur - English oak
- Ricinus communis - Castorbean
- Salix gooddingii - Black willow*
- Salix laevigata - Red willow*
- Salix lasiolepis - Arroyo willow*
Less susceptible to ISHB/FD (causes branch dieback), and/or the beetle commonly colonizes at the margin of canker diseases.
- Acacia melanoxylon - Australian blackwood
- Acacia spp. - Acacia
- Acer paxii - Evergreen maple
- Acer palmatum - Japanese maple
- Acer saccharinum - Silver leaf maple
- Aesculus californica - California buckeye*
- Ailanthus altissima - Tree of heaven
- Albizia julibrissin - Mimosa
- Alectryon excelsus - Titoki
- Alnus rhombifolia - White alder*
- Archontophoenix cunninghamiana - King palm
- Baccharis salicifolia - Mule fat*
- Bauhinia variegata - Purple orchid tree
- Brachychiton populneus - Kurrajong
- Camellia semiserrata - Camellia
- Castanospermum australe - Moreton Bay chestnut
- Casuarina equisetifolia - Australian pine tree
- Cocculus laurifolius - Laurel leaf snailseed tree
- Corymbia ficifolia - Red flowering gum
- Cupaniopsis anacardioides - Carrotwood
- Dombeya cacuminum - Strawberry tree
- Erythrina caffra - Coast coral tree
- Erythrina coralloides - Coral tree
- Erythrina falcata - Brazilian coral tree
- Fagus crenata - Japanese beech
- Ficus altissima - Council tree
- Ficus carica - Black mission fig
- Gleditsia triacanthos - Honey locust
- Harpullia pendula - Tulip wood
- Howea forsteriana - Kentia palm
- Ilex cornuta - Chinese holly
- Jacaranda mimosifolia - Jacaranda
- Koelreuteria bipinnata - Chinese flame tree
- Liquidambar styriciflua - American sweet gum
- Magnolia grandiflora - Southern magnolia
- Magnolia virginiana - Sweet bay
- Parkinsonia florida - Blue palo verde*
- Parkinsonia x sonorae - Sonoran palo verde
- Persea americana - Avocado
- Platanus mexicana - Mexican sycamore
- Prosopis articulata - Mesquite*
- Pterocarya stenoptera - Chinese wingnut
- Quercus agrifolia - Coast live oak*
- Quercus chrysolepis - Canyon live oak*
- Quercus engelmannii - Englemann oak*
- Quercus suber - Cork oak
- Salix babylonica - Weeping willow
- Spathodea campanulata - African tulip tree
- Tamarix ramosissima - Tamarisk
- Wisteria floribunda - Japanese wisteria
- Xylosma congesta - Dense logwood / Shiny Xylosma