DESPERATE FOR HELP, Blisters and/or Black spots on the underside of leaves

[davidwood]

Thats like something from a horror movie, I hope you get it cured.

[hoosierquilt]

Charlie,
I had sort of the same thing happen here in Vista, California just recently.  I'm recovering from it, now, thank goodness.  I have several of my older, established hibiscus (but interestingly, none of yours) develop yellow leaves with little black spots on them.  They all dropped off and then I started to see some rather rapid branch tip die back.  Obviously some sort of fungus and probably due to all our prolonged heavy rains in December.  I am going to prune up everything, I've collected all the dropped leaves and will also dispose of my prunings in the trash to try to cut down on the spores going back into my soil.  Going to innoculate with mycorrhizae and fertilize.  I hesitate to spray fungicides or use systemic fungicides since it will kill off all the beneficial fungii.  Any idea what this was??  My gardener told me that "all the hibiscus around here have had this issue", so it seems to be fairly widespread here in Vista.

Patty S.

[Charlie]

That's interesting, Patty. I don't know what it is but if something comes to mind or I hear some good info I will surely pass it on.

I think your program for caring for the plants is a sound one.

Charlie

[hoosierquilt]

Thanks, Charlie.    Just ordered fertilizer from you all.  Saw that it's already on its way, thanks!  I was somewhat horrified when this started to happen, because it was very swift and sudden.  My two double pink trees lost about 1/2 their leaves and had a fair amount of branch tip die back. The other affect hibiscus were not quite so affected, but still I had about 15 other bushes affected to some degree.  They're otherwise extremely healthy.  I have never had anything more than some aphids, which are usually taken care of by a hard spray frome the hose followed by the arrival of lots of local lady bugs. Think this was just an odd fluke due to so much rain and moisture.  We really had a lot of rain on my property - a total of 13 inches in that period of December through beginning of January.  It was pretty darned wet here.

Patty S.

[Charlie]

I'm sure you're right about the heavy and unusual rainfall being involved in the problem. There are a number of what they call water molds that cause plant diseases and there are some fungicides specifically targeted at them. The trick is to find out which is the cause. It's not easy because symptoms can be very similar and usually only a qualified lab can give a definite diagnosis. The fungicides have to be matched to the disease organism to work, and are expensive, and are not 100 percent effective. Most pros will advise prevention over cure for fungus diseases.

Charlie

[hoosierquilt]

Thanks, Charlie.  Fungicides are pretty nasty chemicals (I'm an RN, and this is true even for humans and anti-fungal medications for us human-folk).  I have had a LOT of fungal issues with other plants - mainly my roses - as well.  Everything is looking much, much better now that we've had some sunshire and drier weather.  Interesting to note - one of the more affected single orange hibiscus that is draped over my little pond (most damp place on my whole property) is growing RIGHT next to one of your lovely Rainbow Christy hibiscus (see my little avatar for one of its blooms).  The single orange hibiscus lost almost 1/2 its leaves and had a significant amount of tip die back.  The Rainbow Christy was completely unaffected.  Nothing.  And they are so close to each other they are intertwined.  Not one of your hibiscus were affected.     I find that very interesting!

Patty S.

[Darkhorse]

Bart, do the lesions look like this? 

I thought I was done with this problem until just recently.  This came in on my Night Runner plant that I referenced earlier in this thread.  Thought I got it all but it resurged this winter.  Blackish, raised lesions that look like blisters on leaf bottoms?  They manifest differently on different cvs... the first picture is the bottom of a Night Runner leaf.  The second and third are of the mystery cv.  The problem was confined to NR until this winter-- the mites seem to be doing a fantastic job spreading this malady around.

[roadrunner]

I've had this same problem on several of my plants for about a year now. The first time I noticed it was about December 2009 on Bonnie Lass and Night Runner. It spread to several other cultivars rather rapidly. I also had my first major spider mite infestation at that time and was too ill to get after it. I haven't found any treatments for it so far other than removing the infected leaves and keeping after the spider mites which I agree seem to spread it like wildfire. I don't like using fungicides and don't want to go the Wilt Proof route either. Currently I'm rotating Neem oil, Pyola, Safer's new End All, and the old standby rinsing the plants for the spider mites. The expensive miticides are out of my price range. Some cultivars seem to handle this better than others. Chariots of Fire for example gets a few spots here and there, but they don't explode everywhere and defoliate the plant. Others like Blonde Ambition and Cindy's Heart got hit a lot harder and I thought I was going to lose both because they lost so many leaves and new growth initially was very weak. Blonde Ambition is still looking a bit weak but CH seems to have recovered. This seems harder on the slower growers. I've lost five plants so far: Heaven Scent, Night Runner, Blue Bird, Love Story, and my treasured Cherry Appaloosa. Heaven Scent is the only one I've been able to replace so far.

I hope someone comes up with a treatment for this soon.

dave

[Nievesgirl]

I haven't found any treatments for it so far other than removing the infected leaves and keeping after the spider mites which I agree seem to spread it like wildfire. dave

Dave I highly suggest just spraying the plants with a high pressure water sprayer. I tried everything ! and could not get rid of my spidermites until I just used a high pressure sprayer. some of my plants are outside in socal winter weather and even with the heavy rains we have been having none of my leaves are dropping. Only my H rosa-sinensis has a few black spots due to the cold. All the other Cv's are doing fine.  I am about to let my bf take some and place them on his porch and I will have to spray them also to make sure I get all the mites off.

If you have the plants in a pot this is what I do. I place plants on their side and spray them and rotate the pot so I make sure I blast water on all the underside of the leaves. ( I do not want the water getting onto the soil because most of the time they have been watered already. I don't want them getting their roots to cold either) Then I place the plants up right and spray the top of leaves really quickly so a lot of water wont be in the soil. I did this once a week for only 2 or 3 weeks.

I bought miticide off ebay that licensed nurseries can only get. I was going to use it but Charlie said I need to cover my arms and clothes and have a mask. I don't want to mess with all of that so I never used it lol.

I will try to get rid of the white flies, aphids, and mites in these up coming weeks. I need to do my indoor plants more often like every other day in a hot shower. Its really tasking on my back and knees to carry the plants to the tub so I haven't been spraying them like I should and this is why I still have the spider mites.

[Darkhorse]

Now this is starting to worry me even more...  deadly or not I don't want this spreading throughout my collection.  I'm determined to get to the bottom of this.  I'm not sure if this is fungal, bacterial, or viral.  My guess is that it's not fungus, as the leaves haven't been exposed to humidity or moisture at all.  But I could be wrong.  The first step is for me to find out what I'm fighting.

I've separated out all symptomatic plants-- I hope nobody else pops up with spots.  Affected are Buttercup (ouch, such a rare cv), Sleeping Beauty, In The Mood, Valentine's Day, mystery cv, and of course Night Runner.



Dave, are all your plants from HVH or have you gotten any from other vendors?  If you have purchased from other vendors, I'm curious to see if the plant that started the infection was from the same place.  Interesting that you mention Night Runner.


Weird that this only shows up on the leaf bottoms... and the blister can't be wiped off as in Bart's case.  Charlie what do you make of all this?

[roadrunner]

Thanks Kerry. I'm pretty much doing what you suggest now though I use one of those hose end nozzles that have multiple spray selections instead of a high pressure sprayer. I find that I'm able to get very good spray pressure with it and am also able to do it outside on nice weather days. I also tip the pots on their sides to get the undersides of the leaves thoroughly but only do this for the ones that need watering. The plants that don't need watering get sprayed with one of the sprays I mentioned earlier.

I started growing the landscape hibiscus 10 or 15 years ago in containers and discovered these hybrids in 2004. The only pest problems I had all those years were aphids. The spider mites didn't show up til about 2 years ago and the first problem with whiteflies was about a year ago. Most of my collection  (I'm afraid to count how many) overwinter inside the house in 5 different areas. I have 3 south facing windows which contain most of the collection and about a dozen are under a couple of skylites. I basically treat one section at a time whenever they get dusty or if I seen even one mite. I either do the high pressure washes or spray with one of the oil sprays. Three of the five areas have been spider mite free for over a month now. I did find about 5 plants with a few mites in the living room a couple of days ago and gave them a good washing. If I see any more mites in the next few days I'll hit them with the Safer's End All which is supposed to kill all stages of the little buggers including eggs. Over time I guess I'll find out if those claims are valid. I think I've at least got the situation back under control for now, but the weird black spots are still showing up on a couple of plants.

Jordan. With the exception of the first 3 exotics I bought from a Florida vendor back in 2004, my whole collection of somewhere near 70 plants I estimate is from HVH. My first order from Charlie was in 2007. My Night Runner was a rather sickly plant when I got it and I thought I could bring it around. It didn't happen. It managed a couple of small blooms before it died rather quickly. It had some sick looking leaves and the growth was very weak, but didn't have those raised black spots.  I've lost several plants that did have the raised black spots. I think the large loss of foliage because leaves with those spots eventually turn yellow and either drop off or need to be pulled off has a similar effect to what happens with a severe spider mite infestation. If memory serves I believe Charlie thinks it could be an opportunistic infection brough about by a spider mite infestation. Some of my plants became so weakened that they just never recovered. I agree that it's probably not a fungus since wet foliage and high humidity don't seem necessary to spread it. Spider mites can certainly help spread it but don't seem necessary for that to happen either. My uneducated guess would be it is bacterial. Now what would be effective against a bacterial infection? Something with copper in it maybe?  I just noticed that my Palm Springs has a large number of those black spots on new growth and no mites to be seen, so I may just throw it out and order another one. It certainly needs to be isolated from all the others. This is definitely frustrating.

dave

[Charlie]

Dave and Jordan, I'm not sure what to make of this. It's not happening here so I can't do any experiments or make any direct observations. I do have a consultant I can use who is a national expert on plant diseases. If I get hold of some good samples of the problem I can send them to her lab and she might be able to diagnose the problem.

Unfortunately, neither bacterial nor viral diseases have any good treatments available. A fungus would be easier but an exact diagnosis is necessary in order to know what will effectively treat it. There is something called agromycin that is an antibiotic for plants, but it doesn't work very well on bacterial pathogens that effect hibiscus. Viruses are spread by insects so the most effective thing to do if virus are suspected is to control insects as much as possible.

Cindy has researched and written an article in the upcoming Feb newsletter about some new studies of plant immune systems and possible ways to stimulate them. As she points at this is a young science and not a lot is known other than that plants do respond to pathogens and do have a unique type of immune response, different than mammals. In any case she points to some suggested ways for improving plant's own protective biochemistry that anyone can experiment with.

Charlie

[Cindy]

I have a sick Torch Song and the only bugs that have ever infected it are spider mites, so I know that's where it got the illness. Mine looks/sounds different than your spots, Dave and Jordan. Mine sounds more like what Patty describes, and I think mine looks like one of the "spotted" viruses. It already killed 2 other of my hibiscus - all 3 were ones that got hit with the same spider mite infestation a couple of years ago. Torch Song held out for a long time and barely showed signs of the virus, but it took a nosedive this winter when the cold weather hit, even though it's inside the house. :-(

I've been researching plant immunity for quite a while, and haven't come up with much. All the universities say to throw away sick plants still! But I don't want to do that! I'm determined to find SOMETHING that works when a plant gets a viral or bacterial infection! But so far, all I have is ideas of things to try, not anything that I know works yet. Here's what I've found in the research and tried:

- Super Nova first, in high, steady doses. This often works, especially if I catch it early.

- Dark Energy - I keep trying it and see no results whatsoever, so I'm about to give it up. It's expensive and not working!

- B Vitamins - I have better luck with them as preventatives than as cures. When I lived in the cold mountains, B vitamins helped my plants make it through ice-rimed windows for months on end. As cures for infection, I'm not getting results yet.

- Vitamins D3, C - I just open a human vitamin, pour it at the base of the plant and water it into the soil. I've just started this, so I can't tell if it's working yet. It sort of seems to be working. I was losing a new deformed leaf every day, and haven't lost a single leaf for about a week on Torch Song, since I gave it the D & C, so I'm feeling hopeful.

- Aspirin - I've used aspirin in the past for stressed plants with success, especially cold stress. I've added it to my vitamin mix for my sick Torch Song, but don't know if it will work yet. Aspirin is what plants themselves use to cure themselves, so I figure it can't hurt to give mine a boost of it without the poor sick baby having to produce their own, which is stressful.

- Azelaic Acid - Another natural plant substance in sap that plants use to fight disease. We use it in expensive face creams as humans. I haven't found a source to try it for plants yet, so I don't know how well it will work. But the research looks promising.

I could go on and on on the subject, but you're probably all nodding off already now. These are my best ideas for now! 

[helixturnhelix]

Zzzz

[Darkhorse]

Thanks Charlie, Cindy, and Dave for your replies.  I was reading somewhere that bacterial and viral diseases aren't systemic.  That is, they are confined to the individual leaves unless spread by a vector.  I'm hoping this is true.  I've started plucking off all symptomatic leaves on the mystery cv.  Young leaves don't yet have any spotting so this increases my hope that the problem may not be systemic. 

The problem didn't seem to effect my Night Runner that much this summer.  The leaves were just blemished.  I hope I'm worrying so much for nothing.    I'll continue to update you guys on my experiment with the mystery cv and whether or not it works.  I don't want to have to throw plants away, but I don't want my entire collection contaminated either.

Cindy, very interesting, as I've never heard of giving plants vitamins or aspirin!  I use vitamins for the horses I work with but haven't ever tried anything like that with a plant.  I wonder if a good old-fashioned human antibiotic would work on a plant bacterial infection...?  I can't wait to read that article in the next newsletter.  Good luck with the Torch Song, and hope you're feeling better!