MileHighGirl. Last year I use streptomycin two or three times around bloom time and I did not have any fireblight. I have been working toward growing my fruit organically so I only used Serenade this year and I still donâÂÂt have any signs of fireblight. Am I lucky or does the Serenade work. ItâÂÂs just too early to determine. My fruit trees are a mixture of disease resistant verities and some that are susceptible. My goal is to move more to the resistant varieties. Good luck, Bill

Bill pretty much covers it. I had horrible problems until I removed all of the worst varieties. I have not had a major strikes for three years since I did that. Along with streptomycin you also need to use copper delayed dormant - just before the leaves come out.

This morning I was walking in my orchard and I saw one graft that had bad apple scab while everything around it was clean. I got out my pruning saw right then and removed the graft. Varieties like that spread the diseases, you need to nip them in the bud.

Scott

Milehigh:

I agree as mentioned above that some varieties are more
susceptible to fireblight. What is not mentioned is that
rootstock sometimes plays an important part too.

Some rootstocks are more frreblight susceptible. When used with a variety that is very susceptible too, the chance
of fireblight can increase.

Several years ago a friend showed me a certain apple variety in his orchard. He planted two rows on M7 but his
supplier could not supply more. To finish the block he purchased the balance of that variety on M26.

The spring I visited, fireblight struck and the 2 rows on M26 were wiped out. The same variety on M7 right next to them was clean of fireblight.

My observation is that when planting a highly blight susceptible variety, avoid planting on a highly susceptible
rootstock. This might be of help some of the time when
growing a susceptible variety.

Spartan's thoughts on root stock contributing susceptibility to fire blight is something that I had not thought of. Has a formal study been done? I need to do what I can to reduce risk on the replacement trees that I plant next spring.

Scott,

I will have to think on what you said about disease resistant cultivars. I notice that you have Newton Pippin in your list. I think I will keep trying with it and LEARN TO SPRAY IN THE SPRING! I have been too lazy it seems.

I'm going to order Serenade and Ferti-Lome Fire Blight Spray. If it saves my trees then it's worth it.

Spartan,

I have M.7, G.16, G.11, and G.11/MM.111, I will steer clear of of M.26.

If you'd like to read a very thorough article on the subject, this is a good one.

I believe the problem with FB and rootstocks is not that it brings it to the cultivar but that once a cultivar has it the rootstock can be killed. It starts at the flowers or shoots, after all.

Here is a link that might be useful: Fireblight

Thanks Hman. That is the best write up on fire blight that I have read.

After reading the line: "Finally, even when no blossom blight occurs, damaging epidemics of shoot blight can develop and hail storms can trigger severe outbreaks"

I wonder if MHG's hail damage started some of her fire blight problems?

Yes, thank you, harvestman. This article is profoundly informative, and it's also written in English that I can understand. Thank you also to Paul W. Steiner, Professor & Extension Fruit Pathologist, for sharing this information.

After reading the article I feel I understand the disease much better. I also understand why fire blight has never been an issue before but is now. We had a heavy rainy season last year where a depression held the clouds over the front range for weeks, if I recall correctly. These rains brought about devastating flooding which have been labeled in the "1000 year flood" severity. I had no idea that last years rains had any impact on this years trees.

Has anyone used the Maryblyt program mentioned?

If you've never had FB before than you may not have it again. I have never had it on consecutive years at the same site- which pretty much shows how weird the disease is. My clients have never opted for any extra spray to help control it.

I'm managing about 100 sites with anywhere from 5 to 500 trees and in the years I've been doing it I've lost about 4 pear trees the whole time. Apples have never gotten it bad enough to even cost a scaffold branch. Pears half the time recover and half the time have died.

I don't leave stubs, just prune out the entire blighted shoot, at my convenience, because the problem isn't that serious here.

I have some fireblight right now, but it is also cool damp and foggy a good part of the day. I am going to wait for the temps to dry up so I can do some pruning....ugh

My trees look like they are doing better. Maybe I'm just paranoid.

I have a question for future reference. I bought both Streptomyces lydicus and Streptomycin Sulfate. Would not the Streptomycin Sulfate kill off the Streptomyces lydicus if used in conjunction with each other? I believe both products said they could be added to other sprays, but it I am questioning this.

I should have said pears have died on me half the time when they have it bad enough to lost whole branches. Not half the time when they suffer a little shoot blight.