Treating fireblight on pear tree. Apply copper in the winter as well?


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Hello, I have a pear tree with fireblight, and I've been told I should spray it with horticultural oil in the winter when the leaves are off. I'm in western Vermont, and we don't have too many days above 40 degrees Fahrenheit in the winter (when the manufacturer says the oil can be applied), but we are forecasted to have a 45 degree day next week, without the possibility of rain that day or the day after, so it looks like that will be a possibility. Since many growers mix in copper fungicide with the oil to kill off the blight, I'm wondering if that would be the time to do it as well. (I've no experience with fireblight). The horticultural oil apparently acts to smother the blight, though the blight IS apparently dormant in winter in a colder region like mine. Thanks in advance for your advice!
 
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Maybe, I only spray with copper detergent. But personal experience is the best, in time you will understand what works for you.
 
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Dormant spraying is effective for some pests and diseases, but most protocols for Fireblight (Erwinia amylovora) recommend spraying from bud break to bloom. There are more precise methods for determining when to spray, but these require constant monitoring of temperature and humidity. Copper can damage growing leaves and fruit. Copper sprays are less damaging to plants if mixed with lime (Bordeaux mixture).

Part of the reason there is so much difference of opinion about copper for Fireblight is that copper is not that effective alone. Still be ready to prune off any new infections as soon as they are observed. Sterilizing tools between cuts is prudent.

If your tree already has fireblight from the previous season, it may be too late to prune it out. Consider replanting with resistant cultivars.
 
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So this idea of using copper to impact a bacteria is like pointing out that the copper in a brass door knob is self sterilizing. But the tree is not covered in copper after spraying exactly. The UK has begun moving away from copper, as it builds up in soil. It seems that this idea of using a fungicide to treat a bacteria has some room for improvement. Oils are useful, and those oils that pass oxygen like the mineral oil in horticultural oil are very useful on plant tissues. I would think more along the lines of a bacteria-cide. The quantity of spraying seems right, as the oils will weather off, but take longer than a soap. I would think some essential oils like thyme oil mixed into the horticultural oil spray might be a good idea. I have used weakened betadine and stopped pathogens. But it has to be a continuous spray program, and waxes can be problematic. I want to experiment with microcrystalline waxes as they have very high melting points. One cannot suffocate the plant though so we will see.
 
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In Texas if the tree is in early stages of fire blight it may be possible to maintain the tree by doing what is stated above but if the tree trunk and limbs have oozing cankers you may as well remove it.
 
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In Texas if the tree is in early stages of fire blight it may be possible to maintain the tree by doing what is stated above but if the tree trunk and limbs have oozing cankers you may as well remove it.
So basically a systemic is needed? I have some of the streptomyacin type stuff - actinovate. There is also another used on plants. I cannot remember the name just now. Could one inject the antibiotics like they do Imidacloprid? I know the fear here is that the garden targets are also exactly what the medical community fears will become immune to antobiotics so we are pretty much heavily restricted.
 
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Fireblight isn't curable, though you can cut off infected limbs before it spreads. Even people who are using antibiotics to control Fireblight are using those antibiotics as a preventative. They spray it on flowers just like they would Copper or Aluminum tris.

No, I do not think that is a good use of antibiotics. Do you?
 
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So basically a systemic is needed? I have some of the streptomyacin type stuff - actinovate. There is also another used on plants. I cannot remember the name just now. Could one inject the antibiotics like they do Imidacloprid? I know the fear here is that the garden targets are also exactly what the medical community fears will become immune to antobiotics so we are pretty much heavily restricted.
AFAIK it is undecided. It seems as if a systemic made by Fertilome with the active ingredient streptomycin sulfate is showing promise on early stage fire blight but if a tree is showing oozing cankers you may as well whack it down. I don't know about actinovate. Here actinovate is used as a control for Cotton Root Rot and it works pretty good but I don't know of any injectables but perhaps it is possible to inject fungicides like they do pesticides into a tree. I suppose if one could get the product into the phloem it would/could work. But I wouldn't try it on fruit trees.
 
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Dormant spraying is effective for some pests and diseases, but most protocols for Fireblight (Erwinia amylovora) recommend spraying from bud break to bloom. There are more precise methods for determining when to spray, but these require constant monitoring of temperature and humidity. Copper can damage growing leaves and fruit. Copper sprays are less damaging to plants if mixed with lime (Bordeaux mixture).

Part of the reason there is so much difference of opinion about copper for Fireblight is that copper is not that effective alone. Still be ready to prune off any new infections as soon as they are observed. Sterilizing tools between cuts is prudent.

If your tree already has fireblight from the previous season, it may be too late to prune it out. Consider replanting with resistant cultivars.
Thanks for your input! Sounds like I should wait until late March to start spraying the horticultural oil. (At the tail-end of winter)
 
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Fireblight isn't curable, though you can cut off infected limbs before it spreads. Even people who are using antibiotics to control Fireblight are using those antibiotics as a preventative. They spray it on flowers just like they would Copper or Aluminum tris.

No, I do not think that is a good use of antibiotics. Do you?
Thanks for the input-- looks like I have some research ahead of me....I did cut off some infected limbs over the summer, but the blight appeared elsewhere.
 
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AFAIK it is undecided. It seems as if a systemic made by Fertilome with the active ingredient streptomycin sulfate is showing promise on early stage fire blight but if a tree is showing oozing cankers you may as well whack it down. I don't know about actinovate. Here actinovate is used as a control for Cotton Root Rot and it works pretty good but I don't know of any injectables but perhaps it is possible to inject fungicides like they do pesticides into a tree. I suppose if one could get the product into the phloem it would/could work. But I wouldn't try it on fruit trees.
Thanks for the input-- no oozing cankers in the tree thus far. At least that's a good sign...
 

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