In my reading…i have read that no pears are truly resistant…
Moonglow- hard to find anyone that says its not fireblight resistant. Even words like excellent resistance are used…but most of the new posts on FB that i see ‘what is this on my pear tree’…are alot of Moonglow pears.
Starking Delicous(Maxine)- makes almost every list as one of the most resistant.
Magness makes almost every list of most resistant.
Harrow Series- makes almost every list of resistant.
Here is a good read for you Clark
My experience is korean giant is moderately resistant similar to pai li. Drippin honey, ya li, kosui, hosui, charles harris, etc. all get fireblight. Drippin Honey is resistant. Maxine also gets fireblight but is moderately resistant.
Perhaps ‘fire blight resistant’ just means the tree doesn’t die or get overly affected as opposed to can’t catch it at all.
Kieffer as an example never dies of fireblight but always gets it. That makes it resistant. Warren doesn’t get it typically at all. Warren is much higher quality than disease resistant types normally are. Orient is known to be resistant but cannot compare to warren in quality. Leona shows no fireblight at all yet but time will tell.
On the same tree, Hosui didn’t get fireblight, but Chojuro did, but the rootstock must have save the tree, I removed a black pear leaf on Chojuro yesterday.
There are truly resistant varities like warren but like i said its a short list. Many of us grow many resistant varities but someone like @rayrose will tell you the extremely resistant types we hrow like plumblee die of fireblight. There are different strains of fireblight. The current strain i have is the really bad strain.
Have lost 3 chojuro trees to fireblight but the one i got at starks last time is doing great so far. Noone knows how resistant a pear is until they bloom and fruit. That is when they really get fireblight! We have experiencè growing warren, potomac, ayers, clarks small yellow, farmingdale, hood many many years and we know how resistant they are. Harrow sweet is moderately resistant and slightly more resistant than harrow delight. Maxine is more resistant than most pears in that class. Never had severe die back on maxine yet. There are many people who swear a leadbetter wont get fireblight and in my limited experience with that pear i believe them Arthur Ledbetter Pear – Bass Pecan .I’m not sure most people would like them. Southern pears are very different normally. @coolmantoole could tell you a few of those he has good luck with Southern Pears - #316 by clarkinks . @krismoriah you dont want me to show you what this strain of fireblight does to harrow pears.
Can you make any correlation between rapid growth vs slow growth in relation to fire blight? Also pruning.
The backyard or home grower tends to ‘make trees grow bigger and faster’ with fertilizers, amendments, watering, mulches and the best of care… which leads to rapid growth. Also due to aesthetics i see many questions during the summer of what do i prune…because they think summertime is the time to prune. Also seems that the average poster on facebook has higher instances of FB… or maybe im just seeing it due to folks only posting problems.
I think i read an old study on this but it was years ago and my mind isnt as sharp as it was.
Also i remember reading that pruning stress will make it more susceptible…i think.
So could a person increase their resistance by not pruning other than fully dormant… and minimizing rapid growth?
Or is that old news? Or not even a factor?
Pruning is definately a factor or anything that exposes trees to more growth or wounds to infect. Fireblight hits only rapidly growing tissue when temperatures make it ideal. The instances of fireblight go up in spring due to rapid growth and ideal temperature. The weather in California is pleasant year round making conditions somewhat ideal for longer. Texas has very high humidity, heavy rain etc like most places in the south making it a hotbed for fireblight. Mississippi is one of the worst places for fireblight. In Kansas we normally have hot very dry summers giving us a break from fireblight. This summer has been different and conditions are perfect for fireblight. Similar to what you see in the south but less rain. It is raining today and 2 other times in July. Two 80 mile an hour wind storms in July. One mild wind storm today with gusts at 30 mph. Thats insignifigant unless your trees have fruit then it breaks branches and allows fireblight to spread. @krismoriah it helps to see actual trees. The one on the far right is half warren on the left (moderate to light producer)of the tree and karls favorite aka ewart on the right (heavy producer). The next tree in the middle is maxine which is a heavy producer of good pears. On the far left is seckle ( small pears and light to moderate production) , behind seckle is clara frijs showing large fireblight strikes. Notice maxine has a couple of strikes. Maxine is more resistant than kieffer which is also considered resistant because it doesn’t die.
Of all the 10+ Asian pear varieties that I have grown and grafted, Shinseiki is the worst. Both grafts got killed by fire blight in 3 years. The second worst is Raja. That’s only on my trees and in my yard.
Korean Giant, 20th Century, Hosui, Kosui, Chojuro, to name a few, have had fire blight on a few twigs. Nothing to kill the branches or the trees.
Have grown southern pears @40 yrs in Houston micro climate zone 8. Spalding, Southern King, Acres Home, Tennosui, and Meadows. Never any blight hits on those varieties. Didn’t care for Tennosui and pulled it. Polar vortex killed everything with exception of Meadows. Meadows is reported to not be self pollinating but loaded with fruit every year. Big freeze killed all apples, citrus, peaches, plums, etc. Trees were not accustomed to 11 degrees and below freezing for 5 consecutive days. My favorite was spalding. Very sweet every year and carefree. Had asians also. Hosui was my fave asian. The one on OH rootstock beautiful tree and fruit. Watery and low sugar every year. Pulled it. The other hosui was on unknown rootstock that was very brittle with small but super sweet and tasty fruit. Grew the 2 hosui about 20ft apart.
I got a PM the other day from someone wondering why i post the things that i do that are outside the norm… i guess i am always learning or trying to learn. I try not to focus on negativity but instead i like to keep moving forward with knowledge and possibilities.
If anyone is interested in a possibility that may or may not happen in the future or perhaps a possibility now there are studies on the milk spray or however you want to culture and use Lactiplantibacillus plantarum as it is a probiotic.
The study:
They were effective in preventing fire blight on pear flowers, fruits and leaves, as well as in whole plants and in a semi-field blossom assay. The present study confirms the potential of certain strains of L. plantarum to be used as active ingredient of microbial biopesticides for fire blight control that could be eventually extended to other plant bacterial diseases.
The ‘biopesticide’
Perhaps this along with Clark’s recommendations will give someone or many that opportunity to grow Pears (or apples) with less instances of Fire Blight.
If you are anti- milk sprays maybe u will be pro sauerkraut sprays. 
Re: outside the norm- That’s when progress and better quality of life happens. New ideas and methods to add to the toolbox can only benefit the group, especially if it’s organic.
Think we are getting very close to spray free orchards. Pears like warren can be grown with little or no sprays at all. The price of chemicals and the dangers they pose increase exponentially as we grow more acres of pears. We simply cannot grow many crops spray free at this time. In my opinion as orchardists we need to focus on what we are good at growing spray free eg. Warren pears, persimmons, pawpaw, blackberries, autumn berries, raspberries. Perennial grain crops will revolutionize agriculture as we know it. Low spray cherries like carmine jewell that yield high with little input are ideal for an orchard. Cj require a couple of simple fungicide sprays a year. Fireblight will continue to be a problem with pears and apples until we decide we want to grow spray free fruits like pears. If we plant nothing else and phase out the problematic crops everything will be fine. Ayers, maxine, warren etc. Listed above if you grew only them could be ignored even in fireblight season. They will get fireblight but the weak link on maxine is it gets it which spreads to vulnerable pears. This year when i needed to pick juneberries, cherries, mulberries etc. Instead i was fighting fireblight. We need time to plant gardens etc. But we wont have that time if we accept spraying pears instead. It all takes time and money. If it costs maintenance money it is the wrong crop for that area. Top working a pear puts me out of production for 2-3 years at most then im back fireblight free. If it comes down to it i would graft every pear to warren if that is all that worked. It wont come to that i hope.
I have a Golden Dorsett, moderate fireblight resistant, so far, I can see one branch turning brown from afar, not sure what’s the reason, maybe the squirrels broke the branch, but the tree is loaded, I don’t even prune, thin or do anything, it’s growing in a tough corner, so far I have over 100 fruit, some are big like a Fuji, no bugs damage either.
This tree is also next to a neighbor with Loquat, a fireblight magnet.
i have New Century Asian pear for 15 yeas now and it’s doing good, never had fire blight or insect damage. However deer got to it once 10 years ago, no issues at all with very little spraying of fungicide. however this year i have been spraying copper on the tree due to all the rain and humidity currently, never know what can happen in that environment. I recommend New Century
Isn’t Kiefer also pretty resistant?
Unfortunately it isn’t. Kieffer gets fireblight very easy it just doesn’t die. Thats valuable because you can get some fruit all the time. Many home owners choose it for that reason. Its a tree that gives pears and doesn’t die spray free. It is a problem for me because i dont want trees that are carrier’s of fireblight. As an example in Texas pineapple pears are big but they do have fireblight. People plant new pears and the new pears die which is frustrating. The old pineapple their neighbors have are infected with fireblight. Why some stores sell bartlett in Texas is beyond me, we all know better. Imagine a map that said ok you live in houston here are the pears you can grow. In Kansas here are the pears you can grow. It would save much frustration if people in some towns in Texas knew Leona, Orient, Ayers worked in their area. If they atarted giving real data compiled from experience and not reading for a change. There are many so called pear experts who believe they know more than our group. The pear information on paper does not even scratch the surface of the data on this site that all of us put together. We have some talented fruit growers here. People like you teach grafting and other things every year which really helps future generations. The more i grow fruit in this area and compare data with other local growers of fruits the more i realize we need much more research done. The research that we have done eventually made this thread a necessity. My suspicion is many growers realize exactly what i’m saying about pears like warren , ayers, maxine etc… kieffer certainly should always be mentioned.
I think the list is small but growing. Ways to test and quantify susceptibility have also improved.
Hessle, Alfa, Bohemica, Alexander Lucas, among others
I would also think that using the Maryblyt program with Blossom Protect or other biologic prevention measure (and some on this forum claim apple cider vinegar is also preventative) would improve their inherent resistance even more
I do understand what the experts are saying and i’m listening to them , but also doing tests of my own along the way. This year has been very telling how wrong the experts are. Ya li had some strikes this year. It is believed to be somewhat resistant to fireblight.
The ones experts call the most Fireblight resistant pear trees like harrow delight were devastated this year by fireblight. @Olpea warned me about a strain of fireblight that hit him on harrow delight around 10 years ago. Exactly like the fireblight that hit me harrow sweet shows strikes but they are not as bad. The additional harrow pears i was going to add im no longer adding.
Unfortunately that means all documents are now questionable.
The experts are simply wrong the fireblight strain i have had in the past harrow delight was resistant against. The new strain i have now it has no resistance against.
Harrow sweet has some resistance. Blakes pride and tyson have resistance so far but neither have fruit at the moment after the storms.
This is a kosui
Drippin Honey getting a few strikes but it is holding its own. Some leaves were hit with rust.
Pai li is moderately resistant. As you can see fruit and branches are showing no strikes. It can get strikes.
Clapps favorite definately fireblight susceptible but a great tree in every other way.
