Pests and Diseases of Fuchsia and Geraniums by Ronald Kok

Watch out… there are far more Fuchsia and Geranium diseases and pests than we would care to imagine!  Thank you, Ron Kok, for the detailed examples in your presentation! Oh dear!

Fungi, Viruses, Bacteria

Fungi produce spores to multiply and thrive when humidity and temperature are suitable.  85% of diseases are fungal.  Viruses need a host to multiply.  There are a thousand different plant viruses!  Bacteria can be good or bad.  Most are saprotrophic, that is, they feed off of dead or decaying organic matter. Most soil bacteria are not harmful.

Fuchsia Diseases

Ron showed the Club members photos of various diseases to aid in identification.  Some of the fungus problems discussed were: Powdery mildew (Podosphaera), Downy Mildew (Peronospora), Fuchsia rust (Puccinastrum epilobii), Botrytis (Botrytis cinerea); some of the virus problems were: Wilt Virus, Cucumber Mosaic virus. If you are concerned about a particularly important plant, you might consider sending leaf samples to a testing facility.  The Plant Health Laboratory in Abbotsford provides diagnosis of plant health problems.

Geranium diseases

Some of the fungus problems discussed were: Botrytis cinerea (Grey mould), Pythium (Black leg), Geranium rust (Pucinnia pelargonii); some of the virus problems were: flower break, tomato spotted wilt, ring spot.  Bacterial wilt (Ralstonia solanacearum) is a soilborne bacterial pathogen and Oedema is a problem of the roots taking up more water than they can transpire.


Pests not only feed on plants but some, such as thrips, aphids, and whitefly, transmit viruses.    Other pests include mites, vine weevils, fungus gnats and shore flies.  The gardener needs to be aware of temperatures (both soil and air), moisture and humidity, and specific plant needs.  Wet conditions are often a breeding ground for pests. There are some chemical products available.

How to avoid infection

Ron had some great tips for us including: buy from reputable nurseries, don’t bring in cut flowers, disinfect your tools and pots, use bagged soil not garden soil, bleach your potting table, isolate or discard sick plants, regularly check and fertilize your plants.


Keep your plants healthy and use a magnifying glass! There are still some environmentally friendly Fungicides and Insecticides available, such as products from GreenEarth, Safer’s, and Ortho. If making your own solutions, use plant safe ingredients. Organic fertilizers and kelp are better than powdered chemicals.

Although the myriad of potential problems seem a bit daunting, Ron gave us some great tips. Being aware and vigilant is a good start. Seeking the help of an expert is too! Thank you as well to Lidy Kok for adding extra tips of her own during the question period!

You can find some useful descriptions and photos of various diseases on Wikipedia.

For the full article on “Fuchsia and Geranium Pests, Diseases, and Viruses by Ron Kok”, please check your Eardrop newsletter. What a great reason to join the BCFB Society and have access to our publications!


Ron Kok (speaker bio. by Melanie G.) Ronald Kok received his horticultural training at College in the Netherlands. After college Ron worked at the Institute of Plant Genetics at the University of Amsterdam, in the Petunia breeding program. In 1974 Ron and wife Lidy immigrated to British Columbia, and Ron worked at the Agriculture Canada Research Station in Agassiz, doing non-soil media research for the Tomato and Cucumber industry. He progressed to the Agriculture Canada Research Station at UBC where Ron grew hundreds of plant species to supply the scientists with specimen for virus research. One of the technicians was cleaning up virus from Fuchsia stock by cultivating the meristem of popular Fuchsia varieties and heat treating the plantlets. This is where Ron’s interest in Fuchsias started. Later he worked for the Vancouver Parks Board Greenhouses, and the Bloedel Conservatory where he grew a wide variety of annuals and the Fuchsia trees for the city parks – Some Fuchsia tree specimen were 30 years old. At this time Ron and Lidy were thinking of starting their own greenhouse business and in 1979 they purchased a 5 acre parcel of land in Pitt Meadows where they build their home and first greenhouse. Over the years the business grew and greenhouses were added and the focus shifted from wholesale to retail. September 2017 Lidy and Ron transferred the business to their oldest son and daughter in law and Ron retired. (Ron proudly announced that their son recently received a Best Business Award!) Now Ron is busy renovating their new home and still grows a few houseplants. Lidy and Ron have been members of the BC Fuchsia and Begonia Society since 1997.