Psylla or Fireblight

I think I know the answer to this, but would like some second opinions. Sometime last year @MES111 posted a really good thread about pear psylla Recurring Problem Pears Every Late Summer

I posted some pics on that thread of a Bartlett and a Harrow Sweet, which I thought had gotten hit by fireblight. After reading all the comments on the thread, I started questioning to myself if the Harrow Sweet might have been affected by psylla instead.

I cut down the Bartlett, but kept the Harrow Sweet and took a pic yesterday. My question, do you think this is the result of fireblight, or can psylla shock do this to the bark? @alan I’d particularly like for you to take a look at this please. I know you deal w/ a lot of psylla in NY.

I’m getting more pears, and would like to know if I need to start thinking about psylla.

Its screaming “fireblight” for me, but I don’t get pear psylla.

Yes, Scott is hearing it right I think. Psyla stain is concentrated in the small wood and covers all of it.

Hey I’ve never had either. But have had sooty mold from aphids and scale. That would be the same as psyla, a surface cosmetic issue. If the bark is sunken and dead, not sooty mold from psyla, aphids, or scale.

Scale and psyla are only superficial if you can control them and psyla is a real balls buster when it comes to town. It is the PCurc of commercial pear production, in the NE, but much worse because it keeps coming all growing season.

But by superficial you mean surface, as that’s where the symptom rests, but the psyla is sticking its siphon inside the vascular system and sucking the life out of essential shoots and the tree itself.

Yes by surface I meant the discoloration on those branches. Pear psyla is a very serious issue.

I’m using a smart phone to view the picture but it looks like blackrot or fireblight to me. Blackrot is very common in this area.

So much for FB resistance in Harrow Sweet, if that is what it is.

FB resistant cultivars get put to the test here so even Kieffer gets strikes here. Olpea and I are relatively close and this FB kills even trees like Bartlett to the ground at times. Our conditions are perfect at times for it.

I feel bad because I recommended that variety to Olpea. However it is only considered somewhat resistant.

Actually Alan I think we both planted Harrow Sweet at the same time (or w/in a year of each other).

It was a terrible year here last year for fireblight and this tree was next to a Barlett which, to use Clark’s words, was almost killed to the ground. I’m seriously wondering if the high exposure to fireblight overcame some of the resistance of the Harrow Sweet. I’ve never seen a fireblight strike on it before.

Thanks to all for the comments. I’m going to proceed as if it was fireblight. That’s initially what I thought it was last summer, but since fireblight and psylla shock can look a lot alike, I wanted to be sure. As far as I know, I’ve never seen psylla here.


Psyla has never created the sudden death of leaves that look scorched and stay on the shoot for me- they can cause premature leaf drop, however. They don’t cause that damage to big wood, in my experience, and the year before last one site I manage had just terrible psyla- the wood is still stained but growth has returned. No pears, of course, and the trees were productive before the invasion.

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It seems a bit odd that if it is fire blight that the blackening is where it is and doesnt appear to have originated from a typical entry point, unless it is simply out of the picture provided.


It could be. I can’t remember if the shoot coming out on the right is black clear to the end, which could be the entry point, if that’s what you mean.

I’ll check tomorrow.

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Yes that is what I mean.

Honestly I have seen the most resistant pears show strikes here so the advice was not bad rather we had a wet year, perfect temps so the perfect fireblight weather conditions. People in my area lost entire home pear orchards. If you asked several experts like yourself they would all give that same advice.

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Clark, you are sweet. I’m OK, I just feel a little bad for Olpea.

I don’t grow in an area where FB is terrible, although it can be at some sites and some years. Last two I’ve seen more of it than the previous 25, however. I’ve never had it in my own orchard, except on a couple small shoots on trees too close together in my nursery.

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The local big box stores have started carrying a few more varieties of pears that have some resistance to FB. Before you typically would see Bartlett, Kieffer, and sometimes Orient. People can relate to the Bartlett so they buy it plus Kieffer or Orient. In most cases these trees get no care other than planting them in the back yard. They grow ok until they start flowering and then the Bartlett last one or two more years and the Kieffer or Orient seem like they could live forever and in most years they offer up a decent amount of good quality fruit with almost no care. Bartlett is a good tasting pear but in my opinion it should be planted by people that can take care of it’s issues. Apparently there are areas that it does well in but I have not noticed any around me.

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Our weather has changed drastically going from 5b to 6a most years. That’s causing warmer springs and they have been wet. The environment being ideal for fireblight and during the pears weakest time (bloom). Those factors have most of my Kieffer’s showing FB strikes let alone more susceptible pears. I grow Bartlett and have for 20 or so years ( not sure) but its one tree and I know the risks. To make matters worse last year the 17 year cicada hatched cutting my trees to pieces during FB season. It made for a busy year. No one grows commercial pears in this area to my knowledge. I’ve done a lot of research and experimenting with pears and its still a work in progress. If I get a trunk strike I cut it out just like a branch even if it means cutting the tree down. Trees grow back and it does happen.


After seeing this post I started reading up on Psylla. Looks like dormant oil is used but are there other ways to protect pear trees from this pest? Does apple trees also attract Psylla?