Pyracantha problem

[Shima]

I've had this pyracantha a long time and it's never had a problem. Now in the last few months it will drop leaves overnight. They turn brown at the tip and in no time are all brown. It seems to sweep through like the plague and in between it recovers and the leaves are fine. I've plucked about 50% of the leaves as usual getting ready for berry time approaching. I've been lulled into a laissez-faire attitude over the years now I have to get serious. I'm going to spray and drench with a broad spectrum systemic fungicide.
Anyone else have experience with this problem?


Bruce

 

[milehigh_7]

@Smoke @Brian Van Fleet

 

[Shima]

@Smoke @Brian Van Fleet

?

 

[Cadillactaste]

?

Both have the species...tags so they see this thread. Maybe they may know what is going on.

 

[sorce]

Don't make Smoke pop in with the fungus!

Sho is!

Way way worse this year.

Sorce

 

[Brian Van Fleet]

I'm not sure Shima. Mine had problems last year that I diagnosed as Fusrium wilt. Treatment is expensive, and has only slowed it down.

Looking at your leaves, it seems like more than just black spot, and different than Fusarium wilt. When I searched for other wilts on pyracantha, the closest match I found was one called Phytophthora Ramorum, or Sudden Oak Death. It's a "new" disease, and not widespread, so I don't know how it would have gotten to HI. The link references one variety of pyracantha that is susceptible, and the photos toward the bottom were close to what your leaves show. Do you have any cankers on the trunk leaking sap? Do a search and see what you think.

I hope you nail it down; yours is a nice bonsai.

 

[Smoke]

Of all plants suitable for bonsai, pyracantha has to be at the top of the list as "least desirable" for a tropical island. Leaf blights for the rose, apple, pear family of which pyracantha belong, are numerous. They are also some of the most ravenous and least treatable of the bunch. The only plants more suscceptable to blights are the night shade family and grapes. Fire blight is the most common and most difficult to contain. It requires total removal of infected branches to control and for a yard plant this is acceptable while for a bonsai it is devastating. Most of the infecting fungus on pyracantha comes via insects and birds which forage over the prolific flower bracts in early summer. The infection is then transmitted to branch tissue and continues to destroy the plants through its lymphatic system. Weeping cankers will also supply additional ammo for marauding insects and bees to spread the disease.

final note.....plant destroying blight on pyracantha is not a option of "if" ...but "when".

 

[petegreg]

Looks like fungal or root problems. The picture is not sharp enough, but, sorry for expression, I can see some mess on the foliage...aphids? they like them too, and I'm not 100% sure I can't see some scale insects on the bark.

 

[Shima]

Both have the species...tags so they see this thread. Maybe they may know what is going on.

Figured. I don't know from tags.

 

[Shima]

Looks like fungal or root problems. The picture is not sharp enough, but, sorry for expression, I can see some mess on the foliage...aphids? they like them too, and I'm not 100% sure I can't see some scale insects on the bark.

Yes, it's messy. Leaves are the result of spraying for tiny white spots on leaves and berries. Not quite sure what it was but it's gone. Or at least dead. No scale on bark.

 

[Shima]

Of all plants suitable for bonsai, pyracantha has to be at the top of the list as "least desirable" for a tropical island. Leaf blights for the rose, apple, pear family of which pyracantha belong, are numerous. They are also some of the most ravenous and least treatable of the bunch. The only plants more suscceptable to blights are the night shade family and grapes. Fire blight is the most common and most difficult to contain. It requires total removal of infected branches to control and for a yard plant this is acceptable while for a bonsai it is devastating. Most of the infecting fungus on pyracantha comes via insects and birds which forage over the prolific flower bracts in early summer. The infection is then transmitted to branch tissue and continues to destroy the plants through its lymphatic system. Weeping cankers will also supply additional ammo for marauding insects and bees to spread the disease.

final note.....plant destroying blight on pyracantha is not a option of "if" ...but "when".

Thanks Al. I've known of the dread fire blight for ever but never been affected by it here or in California. It's the pancreatic cancer of fungus's. Not sure if up here qualifies as tropical. No typical tropical trees or plants here. Never over 80F

 

[Shima]

I'm not sure Shima. Mine had problems last year that I diagnosed as Fusrium wilt. Treatment is expensive, and has only slowed it down.

Looking at your leaves, it seems like more than just black spot, and different than Fusarium wilt. When I searched for other wilts on pyracantha, the closest match I found was one called Phytophthora Ramorum, or Sudden Oak Death. It's a "new" disease, and not widespread, so I don't know how it would have gotten to HI. The link references one variety of pyracantha that is susceptible, and the photos toward the bottom were close to what your leaves show. Do you have any cankers on the trunk leaking sap? Do a search and see what you think.

I hope you nail it down; yours is a nice bonsai.

Interesting. Another "new" disease is Rapid Ohi'a Death. https://cms.ctahr.hawaii.edu/rod/Home.aspx
If ROD continues this island and eventually the others will be decimated. (To say nothing of my collection) Sudden Oak Death could come over in the tire treads of cars shipped here. Just one of many ways invasive bugs get here. No oozing cankers here. I'm thinking overfeeding might have triggered the problem. Or over watering. It's a problem growing in unnatural conditions.
"All things arise and pass away."

 

[Smoke]

Thanks Al. I've known of the dread fire blight for ever but never been affected by it here or in California. It's the pancreatic cancer of fungus's. Not sure if up here qualifies as tropical. No typical tropical trees or plants here. Never over 80F

Tropical climate, mean humidty

 

[Shima]

Tropical climate, mean humidty

Right. Wasn't sure if tropical has to be hot too.

 

[Smoke]

Right. Wasn't sure if tropical has to be hot too.

Thats a misnomer