Pear rust

Take my advice: if you see signs of disease on a plant, act on it straight away before it gets worse. Last month I noticed individual bright orange spots on several leaves on my conference pear tree … and I ignored them.

Orange-red spots on leaves: first sign of pear rust

Orange-red spots on upper surface of leaves: first sign of pear rust

One month later, I realised that almost a third of all the leaves on the tree were sporting this season’s colour – rusty orange-red!

Pear rust on leaves, but the fruit is unaffected

Orange spot is the new black spot – but the fruit is unaffected

On closer inspection I found some rather gruesome brown, gall-like growths on the corresponding lower side of each leaf, with alien hair-like projections.

Pear rust: warty gall on the underside of the leaves with hair-like projections

Ew! Warty gall on the underside of the leaves with hair-like projections

With the help of Mr Google, it wasn’t difficult to identify: European pear rust, caused by the fungus Gymnosporangium sabinae.

Breaking pear rust’s life cycle

Apparently, fungal rusts need a living host at all times to survive, so the life cycle of this particular nasty requires two host plants. This summer/autumn, my pear tree has played host to the fungus. Normally, it would then release spores from the underside of the leaves and restart the party on a neighbouring juniper tree. Being evergreen, the juniper would harbour the fungus though the winter, releasing spores in summer to reinfect my pear tree.

I can only hope that by painstakingly removing all the infected leaves (yes, I got on a ladder and cut off and binned every last one of the little blighters) that I have broken the cycle, but of course I may have been too late and spores may already have been released. If the culprit juniper is infected again, then my tree might well get reinfected next year and so the cycle will continue. As it is unlikely that I will be able to track down the culprit juniper, I will have to be more vigilant next year and tackle any infection as soon as it materialises.

The consequences

If left unchecked, heavy infections can reduce the yield of fruit, and I have had noticeably fewer pears this year. More worryingly, the infection can cause cankers in the bark (isolated dead areas), which can make the tree more susceptible to bacteria, fungus and insect attack.

The solution

There is no suitable fungicide available to home gardeners if you want to consume the fruit off your tree. And why have a pear tree if you’re not going to eat the pears?!

So all you can really do is try to break the cycle of  infection by removing as many of the infected leaves as possible and putting them straight in the dustbin or burning them. I appreciate that if you have a huge old pear tree this might not be practical (mine is only 4 years old).

Pear rust: bin or burn the affected leaves

Bin or burn the affected leaves

Fastidiously clear all the dropped leaves from under the tree as well. If your tree has got canker, then you’ll need to cut it out of the bark. I’m hoping I won’t get to that stage!

A healthy tree will fight off infection more effectively, so I will also be clearing around the base of my tree, and giving it some TLC over the next few months, including a good autumn mulch, a winter wash and an early spring feed. I will, of course, also ensure that it gets plenty of water, as we’ve had an exceptionally dry October so far. I’ll also be pruning the tree this winter to avoid overcrowding in the crown and improve the airflow through the branches.

Report your pear rust

Unfortunately, there has been a steady increase in pear rust in the UK over the past 10 years. In order to get a better picture of distribution, the RHS is asking anyone who comes across the disease to report it via its online survey.

If you’ve had a problem with pear rust, please let me know, especially if you have any extra tips for tackling it. Let’s hope next year brings less rust and more pears!


  1. I have had pear rust for the last two years keep removing the infected leaves hoping to break the cycle. I live in Long Eaton Nottingham

    • Keep at it Lorna! I’ve had a few red spots on the tree this year (which I’m removing as soon as I see them) but it’s not as heavily infected as last year, so I think I’m winning the battle.

  2. I am looking up this orange crazy stuff on my pear tree and now know it is pear rust. I am learning slot. I live in ny

  3. Vicky Chadwick

    I live in north west, my pear tree has had rust spots for the last two years, it’s only three years old, never had any fruit yet, have removed the leaves that are infected, and was hoping this year might be different, but have noticed, I’ve a few leaves with tiny bit of rust on, do I persevere , or just get rid and start again, advice would be greatly appreciated.

    • Hi Vicky, I would persevere with it for a while longer, removing the leaves as soon as you see signs of the disease. I have certainly noticed fewer spots the last 2 years by doing this, but it hasn’t gone away completely. Unfortunately, even if you break the cycle between your pear tree and the juniper tree that hosts the disease over the winter, there may be another pear tree in the area that keeps infecting the juniper, so you’ll still keep getting the disease. Although I haven’t got rid of it completely, the pear rust doesn’t seem to have affected my yield of pears the last 2 years (my pear tree is only about 6 years old). I had a bumper crop last year and it is heavy with young pears again this year. So your lack of pears may be down to something else. Is the tree on good fertile soil; do you feed it? My apple tree is on heavy clay soil and does not produce much fruit at all, so my mission is to improve the nutrients and see if it starts to yield. It’s worth a try to see if it helps. The RHS has good advice on feeding fruit trees (and mulching in late spring/autumn). Or have you overpruned it? Young fruit trees don’t need much pruning. Again, the RHS has good advice on winter pruning of apple and pear trees. The links are on my blog at, where I have a section on winter fruit tree care. Finally, is your pear tree a self-fertile variety? If not, then you’ll need another variety of pear tree to cross-pollinate it with in order for it to set fruit. I wouldn’t give up on it just yet, but a try a few different things, and give it some TLC through the winter to see if that helps. Let me know how you get on, and if you come across any tips to get rid of the pear rust completely, I’m all ears. Good luck!

  4. Colin Hamilton

    Our pear tree is I would think over 60 years old . This is the worst infection of tree rust in the forty years we have lived here just outside London.

  5. We allotment in Bracknell, Berkshire. Pear rust appeared on our 2-year old Williams tree on the allotment. We only noticed it today as the beautiful pears had mysteriously disappeared too. We have picked all the infected leaves off both this and another small pear and one apple which are all growing together along an espalier.

    • I hope it helps. Sad to say I have had the problem again this year and I haven’t been quick enough to remove the leaves, so I’ll probably have it next year too. On the up side, I still got a fair few pears though.

  6. Hi, I have pear rust on my tree at my allotment and my allotment neighbour has the same problem. We have been removing the infected leaves but it is so bad that would mean pretty much removing all of them on mine. We are trying to coordinate our efforts but we are starting to wonder if there are other hosts nearby. Does anyone know how far can the airborne spores travel?

    • I don’t know the answer to that but would love to know the answer if anyone else out there knows ….? Good luck with your efforts. Even if you don’t get rid of the pear rust your pears should be ok.

  7. Thanks for putting this information online I had literally no idea what this is and didn’t notice the infection until it was well established. Will remove the leaves shortly now I know how to deal with it. I’m surprised there are no available fungicides we can use; hope it doesn’t affect next year’s crop. Big thank you.

    • Sad to say it’s back on my pear tree with a vengeance this year, so I guess I didn’t remove the leaves soon enough last year. Hope you have more success than me. Do let me know!

  8. Just a question – if you use a chemical fungicide, is it safe to eat the fruit the following year, or will you never be able to eat the pears? (I have a two year old pear tree with the fungus)

  9. Can I ask any gardeners reading this if they have pear rust on their trees outside the areas mapped in lime green on this map to add a rough note of location (nearest town in county for instance). My interest is as a naturalist, recently it’s become apparent that there’s perhaps still quite a lot to learn about this pest (see this link or twitter discussion:

    Many thanks,

  10. Margaret huckerby

    My 6yr old pear tree has red rust , am gutted ,unfortunately I am too infirm to be taking leaves so I will just have to let it have it’s way

  11. Yelena Khais

    This spring my neighbor planted a few juniper trees in his yard, and my 4 year pear tree became infected by rust. I am not sure how to tell my neighbor about the issue. I can’t ask him to remove those trees. What should I do?

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