UC IPM Online UC ANR home page UC IPM home page

UC IPM Home

SKIP navigation

 
  Printer-friendly version

How to Manage Pests

UC Pest Management Guidelines

| More pests | More crops | About guidelines |

Floriculture and Ornamental Nurseries

Host-Pathogen Index

(Reviewed 3/09, updated 3/09)

In this Guideline:

The host-pathogen index is a list of ornamental hosts not covered in the Disease Control Outlines and some of the pathogens that attack these hosts. Diseases covered in Key Diseases are noted with an asterisk.

African Violet (Saintpaulia ionantha)
  Bacterial blight Erwinia chrysanthemi
  Foliar nematode** Aphelenchoides ritzemabosi
  Gray mold * Botrytis cinerea
  Phytophthora crown rot * Phytophthora parasitica
  Powdery mildew * Erysiphe cichoracearum
    Sphaerotheca fuliginea
  Pythium root rot * Pythium spp.
  Rhizoctonia stem rot Rhizoctonia solani
  Ring spot physiological (cold water and light)
 
Christmas cactus (Schlumbergerabridgesii)
  Crown rot* Phytophthora parasitica
    Pythium aphanidermatum
  Fusarium rot * Fusarium oxysporum
  Gray mold * Botrytis cinerea
  Root and stem rot Rhizoctonia solani
  Root rot * Pythium irregulare
  Stem rot Phythophthora spp.
  Stem rot and leaf spot Bipolaris cactivora
  Virus Cactus virus X
 
Candytuft (Iberis amara)
Alternaria leaf spot Alternaria brassicae
Basal stem rot Phoma lingum
  Club root Plasmodiophora brassicae
  Gray mold * Botrytis cinerea
  Phytophthora root rot Phytophthora spp.
  Powdery mildew * Erysiphe polygoni
  Pythium root rot * Pythium spp.
  Root knot nematode** Meloidogyne sp.
  White rust Albugo candida
 
Cineraria (Senecio cruentis)
  Collar rot Rhizoctonia solani
  Downy mildew * Plasmopara halstedii
  Gray mold * Botrytis cinerea
  Powdery mildew* Erysiphe cichoracearum
  Impatiens necrotic spot/spotted wilt Impatiens necrotic spot virus
  Leaf spot Alternaria cinerariae
  Powdery mildew * Sphaerotheca fulginea
  Root and collar rot * Phytophthora spp.
  Root rot * Pythium ultimum
  Spotted wilt Tomato spotted wilt virus
  Stem rot Sclerotinia sclerotiorum
 
* For additional information, see section on Key Diseases.
** For additional information, see section on Nematodes.
       
Gardenia (Gardenia jasminioides)
  Bacterial leaf spot Xanthomonas campestris pv. maculifoliigardeniae
  Chlorosis iron deficiency
  Petal blight (gray mold) * Botrytis cinerea
  Phomopsis canker Phomopsis gardeniae
  Root knot nematode** Meloidogyne spp.
 
Gerbera (Gerbera jamesonii)
  Bacterial leaf spot Pseudomonas cichorii
  Black root rot Thielaviopsis basicola
  Crown and root rot Rhizoctonia solani
  Gray mold * Botrytis cinerea
  Leaf spots Alternaria porri
    Cercospora gerberae
    Septoria spp.
    Ascochyta gerberae
  Phytophthora crown rot * Phytophthora cryptogea and others
  Powdery mildew * Erysiphe cichoracearum
  Pythium root rot * Pythium spp.
  Sclerotina crown rot Sclerotinia sclerotiorum
  Spotted wilt Tomato spotted wilt virus
  Verticillium wilt * Verticillium dahliae
  White rust *** Albugo tragoponis
 
German violet (Exacum affine)
  Basal stem rot Nectria hematocca
  Gray mold * Botrytis cinerea
  Root rot * Pythium ultimum
  Spotted wilt Tomato spotted wilt virus
 
Gloxinia (Sinningia speciosa)
  Cottony rot and flower blight* Sclerotinia sclerotiorum
  Crown rot Myrothecium roridum
  Crown rot and tuber rot Rhizoctonia solani
  Gray mold * Botrytis cinerea
  Ring spot physiological (cold water and light)
  Root and crown rot * Phytophthora cryptogea
    P. nicotiana
  Root rot * Pythium spp.
  Southern blight * Sclerotium rolfsii
  Spotted wilt Tomato spotted wilt virus
 
Hydrangea (Hydrangea macrophylla)
  Gray mold * Botrytis cinerea
  Powdery mildew * Erysiphe polygoni
  Rhizoctonia stem rot Rhizoctonia solani
  Ringspot Hydrangea ringspot virus
  Root knot nematode** Meloidogyne spp.
  Root rot * Pythium spp.
  Virescens Phytoplasma
 
* For additional information, see section on Key Diseases.
** For additional information, see section on Nematodes.
*** Not reported in U.S.A.
       
Impatiens (Impatiens wallerana)
  Bacterial fasciation Rhodococcus fascians
  Bacterial leaf spot Pseudomonas syringae
  Black root rot Thielaviopsis basicola
  Brown crown canker Rhizoctonia solani
  Crown rot* Pythium ultimum
    Rhizoctonia solani
  Gray mold * Botrytis cinerea
  Impatiens necrotic spot/spotted wilt Impatiens necrotic spot virus
  Leaf spot Phyllosticta sp.
  Root rot * Pythium sp.
  Southern blight * Sclerotium rolfsii
  Verticillium wilt * Verticillium dahliae
 
Kalanchoe (Kalanchoe blossfeldiana)
  Aster yellows Aster yellows phytoplasma
  Edema Nonparasitic; cause unknown
  Leaf and stem blight Botrytis cinerea
  Leaf spots Stemphylium spp.
  Fasciation Cercospora sp.
  Powdery mildew * Erysiphe polygoni
  Root and crown rot * Phytophthora spp.
  Spotted wilt Tomato spotted wilt virus
  Stem rot Myrothecium roridum
  Top-spotting Top-spotting virus
 
Lilac (Syringa vulgaris and S. persica)
  Armillaria root rot Armillaria mellea
  Bacterial blight Pseudomonas syringae pv. syringae
  Crown gall * Agrobacterium tumefaciens
  Gray mold * Botrytis cinerea
  Leaf blotch Heterosporium syringae
  Phytophthora blight Phytophthora spp.
  Phytophthora root rot Phytophthora spp.
  Powdery mildew * Microsphaera penicillata
  Shoot blight Sclerotinia sclerotiorum
 
Pouch Flower (Calceolaria herbeohybrida)
  Cottony rot * Sclerotinia sclerotiorum
  Gray mold * Botrytis cinerea
  Root and crown rot * Phytophthora spp.
  Root rot * Pythium spp.
  Spotted wilt Tomato spotted wilt virus
  Stem rot Myrothecium sp.
  Verticillium wilt * Verticillium dahliae
 
Primula (Primula X polyantha)
  Crown rot Rhizoctonia solani
  Fasciation Physiological; cause unknown
  Gray mold * Botrytis cinerea
  Leaf spot Ramularia primulae
  Root rot * Pythium spp.
  Spotted wilt Tomato spotted wilt virus
 
* For additional information see section on Key Diseases.

PUBLICATION

[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Floriculture and Ornamental Nurseries
UC ANR Publication 3392
Diseases
S. T. Koike, UC Cooperative Extension Monterey County
C. A. Wilen, UC IPM Program, UC Cooperative Extension San Diego County
Acknowledgment for contributions to Diseases:
R. D. Raabe, (emeritus) Environmental Science, Policy, and Management (ESPM), UC Berkeley
A. H. McCain, (emeritus) Environmental Science, Policy, and Management (ESPM), UC Berkeley
M. E. Grebus, Plant Pathology, UC Riverside

Top of page

Statewide IPM Program, Agriculture and Natural Resources, University of California
All contents copyright © 2009 The Regents of the University of California. All rights reserved.

For noncommercial purposes only, any Web site may link directly to this page. FOR ALL OTHER USES or more information, read Legal Notices. Unfortunately, we cannot provide individual solutions to specific pest problems. See our Home page, or in the U.S., contact your local Cooperative Extension office for assistance. /PMG/r280190411.html revised: March 10, 2009. Contact webmaster.