source: Farm and Food Report
It may look pretty with its daisy-like appearance, but scentless chamomile has become a persistent problem across Saskatchewan and a major headache for agricultural producers, since it has become tolerant to most of the post-emergent herbicides we use.
Now scientists at Agriculture and Agri-Food Canada’s Saskatoon Research Centre—with help from Saskatchewan Agriculture and Food’s Agriculture Development Fund—have come up with a unique way to eradicate this noxious weed from our fields. It involves letting nature do the work through biological control management. Dr. Gary Peng is the lead researcher on the project.
“Scentless chamomile is an important invasive species across all prairie provinces. On the list of most troublesome noxious weeds, it is probably at the top. We figured that if we could find naturally occurring pathogens that we could grow through mass-fermentation in our lab and apply these pathogens in environmentally sensitive areas and in crop systems where herbicides are not effective, we might get some good results.”
In theory, this should work. For pulse crops, for instance, there is currently no effective post-emergent herbicide available to control scentless chamomile.
Similarly, on roadsides and right of ways where high-accumulated concentrations of herbicides could create environmental concerns, a biological control method for scentless chamomile would be welcome.
Key to success, of course, would be finding the right pathogen strains.
“We evaluated about 700 pathogen strains from different locations. Many were of the same variety, but gathered from different sites because of the influence environmental conditions can exert on strain profiles,” explains Peng.
Case in point, 20 per cent of the strains tested were collected in Europe, where scentless chamomile is originally from, before it was introduced to our part of the world, likely by an early settler who thought it would make a lovely ornamental plant.
“It probably started out in someone’s back yard and spread very well over the last 100 years, although it has really become more noticeable during the last 20 years or so, possibly because our monitoring system was beefed-up substantially since the 1970s and early 1980s. This has allowed us to keep a more accurate record of the weed’s progression.”
The adaptive success of scentless chamomile can also be attributed to the weather during the 1990s, which favoured the weed’s competitiveness. It had perhaps something to do with higher moisture levels.
“One should also consider the fact that one single scentless chamomile plant can produce one million seeds a year. Basically, once it is introduced, it is very difficult to get rid of. The good news is that our research has allowed us to identify a group of pathogens with a very specific host range — meaning it will only affect chamomile.”
This fungal pathogen called colletotrichum has moderate effectiveness on scentless chamomile but no effect on Saskatchewan crops and native species. In other words, it is exactly what Dr. Peng and his colleagues have been looking for.
“Because of its moderate effectiveness, the colletotrichum pathogen will be combined with an herbicide that also has some effectiveness, and we hope that when the two are combined into a tank mix of pathogen and herbicide, they will provide us with a new weapon to control the weed. This is a really exciting find.”
Dr. Peng is now ready for the next step, which is to mass-produce the pathogen through liquid fermentation, enabling the production of a great number of spores, with the technical assistance of Saskatchewan Research Council facilities. Perhaps we will see a great many less scentless chamomile flowers in Saskatchewan fields as a result of Dr. Peng’s work.
Download Complete PDF Final Report (#199903454) PDF Here.
For more information, contact:
Dr. Gary Peng
Agriculture and Agri-Food Canada
(306) 956-7617
It may look pretty with its daisy-like appearance, but scentless chamomile has become a persistent problem across Saskatchewan and a major headache for agricultural producers, since it has become tolerant to most of the post-emergent herbicides we use.
Now scientists at Agriculture and Agri-Food Canada’s Saskatoon Research Centre—with help from Saskatchewan Agriculture and Food’s Agriculture Development Fund—have come up with a unique way to eradicate this noxious weed from our fields. It involves letting nature do the work through biological control management. Dr. Gary Peng is the lead researcher on the project.
“Scentless chamomile is an important invasive species across all prairie provinces. On the list of most troublesome noxious weeds, it is probably at the top. We figured that if we could find naturally occurring pathogens that we could grow through mass-fermentation in our lab and apply these pathogens in environmentally sensitive areas and in crop systems where herbicides are not effective, we might get some good results.”
In theory, this should work. For pulse crops, for instance, there is currently no effective post-emergent herbicide available to control scentless chamomile.
Similarly, on roadsides and right of ways where high-accumulated concentrations of herbicides could create environmental concerns, a biological control method for scentless chamomile would be welcome.
Key to success, of course, would be finding the right pathogen strains.
“We evaluated about 700 pathogen strains from different locations. Many were of the same variety, but gathered from different sites because of the influence environmental conditions can exert on strain profiles,” explains Peng.
Case in point, 20 per cent of the strains tested were collected in Europe, where scentless chamomile is originally from, before it was introduced to our part of the world, likely by an early settler who thought it would make a lovely ornamental plant.
“It probably started out in someone’s back yard and spread very well over the last 100 years, although it has really become more noticeable during the last 20 years or so, possibly because our monitoring system was beefed-up substantially since the 1970s and early 1980s. This has allowed us to keep a more accurate record of the weed’s progression.”
The adaptive success of scentless chamomile can also be attributed to the weather during the 1990s, which favoured the weed’s competitiveness. It had perhaps something to do with higher moisture levels.
“One should also consider the fact that one single scentless chamomile plant can produce one million seeds a year. Basically, once it is introduced, it is very difficult to get rid of. The good news is that our research has allowed us to identify a group of pathogens with a very specific host range — meaning it will only affect chamomile.”
This fungal pathogen called colletotrichum has moderate effectiveness on scentless chamomile but no effect on Saskatchewan crops and native species. In other words, it is exactly what Dr. Peng and his colleagues have been looking for.
“Because of its moderate effectiveness, the colletotrichum pathogen will be combined with an herbicide that also has some effectiveness, and we hope that when the two are combined into a tank mix of pathogen and herbicide, they will provide us with a new weapon to control the weed. This is a really exciting find.”
Dr. Peng is now ready for the next step, which is to mass-produce the pathogen through liquid fermentation, enabling the production of a great number of spores, with the technical assistance of Saskatchewan Research Council facilities. Perhaps we will see a great many less scentless chamomile flowers in Saskatchewan fields as a result of Dr. Peng’s work.
Download Complete PDF Final Report (#199903454) PDF Here.
For more information, contact:
Dr. Gary Peng
Agriculture and Agri-Food Canada
(306) 956-7617
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