Re: The bacteria (in the hypanthium) need to thrive in the nectary in order to reach numbers sufficient to switch on their virulence. Once this is accomplished you have an infection.
Do you have a good reference for me on this specific topic? When I reviewed the literature, I only found a few things from Pusey. This might explain some cases. Hi Richard, Yes, bacteriologist have been dropping the term “quorum sensing” over the past few years, which is a trait within both pathogenic and beneficial bacteria that allows them to be non-virulent when in low numbers, then, when they sense when numbers are sufficient to overwhelm the host, they all “switch on” their virulence, or if beneficial, the next action they are building up to. This may allow them to avoid triggering host defense mechanisms until it is too late for the plant to successfully defend itself. Look on Google for that term “Quorum sensing” + Erwnia amylovora and you will find some good recent journal articles. Try those below for a start. https://en.wikipedia.org/wiki/Quorum_sensing http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1082838/ http://www.ncbi.nlm.nih.gov/pubmed/17092294 From: apple-crop-boun...@virtualorchard.net [mailto:apple-crop-boun...@virtualorchard.net] On Behalf Of Weinzierl, Richard A Sent: Friday, August 14, 2015 2:27 PM To: Apple-crop discussion list <firstname.lastname@example.org> Subject: Re: [apple-crop] Looking for comments on fire blight management U of I Kane County Extension Office, 535 South Randall Road, St. Charles, IL Rick From: apple-crop-boun...@virtualorchard.net<mailto:apple-crop-boun...@virtualorchard.net> [mailto:apple-crop-boun...@virtualorchard.net] On Behalf Of Vincent Philion Sent: Friday, August 14, 2015 12:49 PM To: Apple-Crop <email@example.com<mailto:firstname.lastname@example.org>> Subject: Re: [apple-crop] Looking for comments on fire blight management Hi Tim! nice to read you! I think there are more sources of fire blight bacteria in the general environment in the northeastern USA due to your woodlots and forests (with feral apples and native hosts such as Hawthorne) as contrasted with the treeless conditions around many eastern Washington orchards. I agree! But still is fascinating to see whole areas without FB and others with FB, despite similar weather. We often make “false positive” predictions because of this = conditions are great for FB, but not FB develops because bacteria are simply not there. We have nice qPCR data throughout bloom to prove it. The bacteria (in the hypanthium) need to thrive in the nectary in order to reach numbers sufficient to switch on their virulence. Once this is accomplished you have an infection. Do you have a good reference for me on this specific topic? When I reviewed the literature, I only found a few things from Pusey. This might explain some cases. We can learn a great deal about interpreting models by looking at the weather data around the time that we are fairly certain that isolated infection events occurred. We can also look at when expected infections did not occur. It would be very helpful to me if any of you would share weather data including rainfall, hourly temperature (or daily temps) and especially leaf wetness readings. Please send data that covers days from first bloom to about 3 to 4 weeks after petal fall. Excel files are a real time saver. We’re Also looking for the same type of data…! Vincent
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