The Tomato Magazine
recent outbreak of bacterial canker in British Columbia, Canada, left greenhouse
growers looking for answers. While unable to provide a cure, Seminis responded
to this outbreak by sending Dr. Kevin Conn, a senior scientist from Seminis’ plant
pathology lab in Woodland, Calif., to visit with growers and provide them with
more information about bacterial canker, its epidemiology and control measures.
“Bacterial canker is the kiss of death to a seed lot,” Conn said. “Our
varieties were not suspect, but we wanted to offer support, now and later on,
to the growers. We’re concerned; we want growers to be successful.”
Along with Seminis sales manager Joep van de Burgt, Conn visited four greenhouses
in the Delta area, some of which had recent problems with the disease and others
looking for more information about prevention.
Conn visited with grower Gert Van Straalen at Millennium Pacific Greenhouse Partnership.
While the producers had not encountered problems with bacterial canker in their
greenhouses, they were pleased to have more information about the disease.
“It was an extremely useful visit,” Straalen said. “Kevin’s
brain is full of information. He showed me some things about bacterial canker
that I had never seen before. He made us more aware of the problem and was very
A real concern for growers, bacterial canker, caused by Clavibacter michiganensis
subsp. Michiganensis, can survive for up to three or more years in infected plant
debris. It can also survive on weeds, volunteer tomato plants and seed. This
disease can be spread by splashing water and the use of contaminated equipment
and tools in pruning, clipping and transplanting operations. Moderate temperatures
and greater than 80 percent relative humidity favor disease development.
Conn recommended many control measures including, but not limited to, the following:
• Only use seed from certified seed lots that have been assayed for the presence
of bacterial canker.
• Wash hands and arms thoroughly with soap and water before working with plants.
• Workers should wear freshly laundered clothing each day.
• Remove all plant debris.
• Check plants frequently. Suspect and infected plants should be removed and
“There’s no silver bullet, no real answer in this outbreak,” Conn
said. “The growers here run such clean operations that it’s hard
to imagine where the bacterium are hiding. I’m very impressed; these are
the most sophisticated growers I’ve met.”
For more information about bacterial canker or to request a copy of Seminis’ Tomato
Disease Guide, contact your local Seminis representative.
© 2006 Columbia
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