Today noticed that my earliest blooming asian pear has a BIG problem. Hoping it isn’t fire blight. We don’t have a big problem with that here as far as I know. Did have a couple of frosty nights in the past week.
Seem to progress from brown spots on petals… then stem turns black. Some leave look “smutty” but seems to be mostly affecting the blossoms. Any ideas?
thank you!
Mary, good to see you online again! Your post made me head right outside to check on my Asian pears. We share a common weather pattern - the warmest, sunniest maritime April in years - but couldn’t find anything similar on my A pears. My flowers, however, are not quite as open as yours. Maybe it’s about to show up.
> A temperature of 65°F or higher in a 24-hour period plus a trace of rain or high humidity (greater than 65%) is necessary for infection. Flowers, which are open for up to 3 days, support rapid growth of the bacteria while older flowers do not.
Even though there’s been no rain, I see that overnight humidity has been at 65% for the past few days. Normally we don’t have issues with fireblight, unlike most of the posters on this forum. But has this unseasonably warm weather pattern come at a price? Check out the mailing below from WSU.
Maybe when we get back to normal cool and rainy, your later opening blossoms will not be affected.
Btw did all your figs pop? Now what to do with them all!
Fire blight risk high with warm temperatures: Reminders
With warm temperatures projected fire blight temperature risk will be high to extreme in many areas starting Friday and over the weekend. Where moisture (including dew) occurs it will be critical to treat open apple and pear bloom for fire blight.
Remember to use high efficacy materials and concentrate on optimal timing. Consider your risk.
Read online at Fire blight risk high with warm temperatures: Reminders | WSU Tree Fruit | Washington State University
Reminders for conventional orchards:
- Antibiotics work best when applied 12-24 hrs before a moisture event when warm conditions signal management. Save streptomycin products for 1 or less applications per year if you miss a preventative spray.
- At best, antibiotics provide 3-4 days of protection. Applications every 2-3 days are necessary during high risk. Rotate modes of action. Cover blooms as they open.
- Acidify your spray tank. Target pH 5.5 (new research shows 4.0 better) to improve efficacy and residual of antibiotics.
- Consider antibiotic mixes in high risk blocks. A full rate of kasugamycin (100 ppm) with a full rate of oxytetracycline (200 ppm), as well as streptomycin (100 ppm) mixed with a full rate of oxytetracycline (200 ppm) have provided improved efficacy in some trials (Oregon 2015-2018). Actigard (2oz) plus an antibiotic applied during bloom has improved the efficacy of antibiotics an average of 10% in trials in Washington and Oregon (Smith and Johnson 2011-2014).
- Good coverage is key. Product efficacy is based on thorough coverage of flowers. Use tree row volume to apply appropriate volumes to cover the tree architecture in your orchard. Products applied every other row or at high speeds may have insufficient coverage and lower efficacy.
- Blossom Protect + Buffer Protect can be applied with antibiotics to extend the period of control.
Reminders for organic orchards:
- Use your highest efficacy materials. Blossom Protect+ Buffer Protect averages 80% control and soluble coppers (e.g. Cueva and Previsto) 65-80% control in WSU trials. Other products may provide only 20-40% control and should be used in mixes, when risk is lower, or when marking risk is too high. For efficacy ratings see http://cpg.treefruit.wsu.edu/
- Product sequence. Blossom Protect+Buffer Protect approaching full bloom followed by copper a few days later.
- Always consider drying conditions. Most biologicals, coppers and biopesticides can mark.
- If using Blossom Protect:
- Apply to every row. Research has found better colonization of flowers by the yeast strains when it has been spray applied to the whole tree. That is, yeasts that colonize pome flowers do not appear to spread flower-to-flower as well as bacteria.
- Apply in good drying conditions. Blossom protect can mark when it is wet.
- Apply twice (or more). Two (or more) applications (e.g. 40% and 70% bloom) for good coverage of open flowers and sufficient time for the yeast to grow and colonize floral stigma.
- Use buffer. Blossom Protect applications with the companion material, Buffer Protect, have shown significantly better control than with Blossom Protect alone.
- Re-apply after lime-sulfur. Lime sulfur applications are both anti-bacterial and anti-yeast and will knock back the populations of an applied biological. Reapply the biological after lime sulfur treatment.
For more information
Example programs: Plan for Multiple Fire Blight Conditions, Be Agile | WSU Tree Fruit | Washington State University
Risk models: https://decisionaid.systems/
Overview Fire Blight | WSU Tree Fruit | Washington State University
For efficacy ratings see http://cpg.treefruit.wsu.edu/https://mailchi.mp/wsu/fire-blight-risk-high-with-warm-temperatures-reminders?e=5a1813c7ef
Chris
Hi Chris… good to hear from you!
Thank you for that info on fire blight. I have been trying to get a little more educated on this. Kind of depressing! I usually have not had this problem. I am worried that it is fire blight. This tree is my youngest and bloom time is a few days before my others. This is the first year it has made lots of blooms. I am wondering if I should take it out or move it to the other end of my 7 acres. It is a seuri li. I read today that this variety is fire blight prone. 
I saw some of the same symptoms starting on my other asian pears but they are days behind in blooming.
Also, very worried about the asian pears being a reservoir and my apples will be blooming soon. I like asian pears but I LOVE my apples!!
I haven’t ever done spraying but I think I definitely need to start!!!
Yes… pretty bummed!
This might be pseudomonas syringae since just the blossoms are affected. Best is to remove any affected limbs/flowers and dispose off site.
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Ack might be early stages of it I also think you should cut it off
Ramv - I was busy doing that today based on your PM message info. Many Thanks! Quite heart breaking!! You had said you had your problem confirmed by a local expert. Was that through the county or state or WSU? I am thinking I would like to find out for sure what is going on.
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Mary,
I live across the country from you. Just want to share that if you have blossom blast pseunomonas syringae, it was very easy to see. Flowers up and down that affected branch wilted and turned black in a day or two. The branch itself did not turn black. The weather was cool and wet. I did not do anything to it. The branch has recovered well. It did not affected the whole tree, just the shaded lowest branch.
I am more concerned that your Seuri has suffered fire blight. Blight tends to strike in warm, wet spring weather. My personal experience with fire blight is that it spreads fast but not as fast as blossom blast (which seems to happen overnight).
I grafted several Asian pears. Seuri is the only one that has got fire blight the following year. In other words, it is the most fire blight-prone among 10+ varieties of Asian pears I grafted, worst than Shinseiki. I am going to remove the graft.
If you are worried about your apples, check out the organic management of fireblight from WSU below. A spray now of lime sulfur + oil, followed by Serenade Opti might be some prophylactic protection. Bonide’s Liquid Copper Fungicide is copper octanoate. Lime sulfur at this stage might cause some russeting on apples, but might be worth it!
This is organic fireblight management from WSU:
### Organic Management
Prebloom. Fixed copper sanitation if fire blight was in the orchard last year.
Early bloom. Lime sulfur plus oil (apples only). One to two applications of biologicals (Blossom Protect). Reapply biological after lime sulfur, which is antimicrobial.
Full bloom to petal fall. Depending on the cultivar russet risk and the CougarBlight model risk follow with copper hydroxide/octanoate (e.g. Cueva, Previsto) every 2 to 6 days (less fruit safe for russet) or Bacillus subtilis (Serenade Opti) (most fruit safe) every 2-5 days during flower/petal fall. Coppers have had higher efficacy than biologicals during bloom in Washington trials. Do not follow coppers with any products with acidifiers. Good drying conditions are important to avoid russet risk.
Petal fall to two weeks after. Continue protective programs one to two weeks post petal fall. Warm conditions during late bloom increase fire blight risk for late blooms still present.
Thank you one and all. I am feeling a little less panicked. I will be removing the seuri li tree ASAP and will be getting going on a spray program which I should have been doing for years.
I am sooo very happy to learn that organic management is possible.
Again… thank you one and all!!
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