More strange leaves

[roadrunner]

I'm getting this leaf appearance on over a dozen plants. The underside of the leaf shows pin prick like spots and what appears to be tiny beads of sap. It appears something is sucking on the underside of the leaves but no mites or webs are visible even with a 20X lighted loope. Plants have also been treated with iron chelate (soil drench) and fulmag of magnesium (foliar spray). No improvement. The leaves if memory serves are from My Blue Heaven. First pic is underside view and 2nd is top view.

Is anyone else on the forum seeing anything like this?

Thanks,

dave

[davidwood]

No idea Dave, but I would say its not something sucking on the leaf, it looks far to uniform for that,I expect Charlie will have an idea but I bet its a deficiency of some sort, hope so, it looks very odd.

[roadrunner]

I've already sent Charlie some pics of this in earlier stages before the yellowing becomes pronounced.  As far as a mineral deficiency I doubt that.  I use the HVH fertilizer, iron chelate, fulmag of magnesium, occasionally the HVH booster, and also the SuperNova at times.  While I have hard water here, it's never been so hard that it's a major problem growing things and I've been here nearly 30 years.  I also flush any possible salt buildup out of the pots occasionally and they even get rain water when I have it which is during our rainy season right now.  I started growing these exotic hibiscus in 2004 and this is the first year I've seen this. Oh, they've also been on Kontos since mid May.  One of the strange things is the pin prick appearance on the leaves in the early stages.  It looks typical of spider mite feeding and then there is what appears to be tiny beads of sap coming out of those spots like something had been feeding as mentioned earlier.  Yet no mites are visible unless they are so small that they can't be seen through a 20X loope.  I've had spider mite outbreaks before and they were not difficult to spot.  The pin pricks evolve into larger areas of paler green which eventually start turning more yellow as in the two photos.  I remove the leaves before they have a chance to fall off.

Between this and another leaf condition which I posted about on April 30th titled "Diseased leaves?", both have been very hard on my collection this year.  I've lost 6 plants and 7 more are in critical condition and I've never been able to save any once they get to that stage. Currently Cindy's Heart, Fabulous, Rebel Rouser, Surf City, Shockwave, White Magic, and Melon Melange are on death watch.  I think MM is actually gone. Earlier casualties were Torch Song, Over the Rainbow, Best of Times, Cherry Appaloosa, Fantasy Charm, and Bonnie Lass.  It's been a rough year for the hibiscus.  I also lost the Acapulco Gold that I posted pictures of a few months ago. It just kept getting weaker.

I added a couple of pics of this leaf condition in earlier stages of development.

dave

[davidwood]

Spent a bit of time today searching the Net for a clue, I did first of think a rust fungus but like I said earlier it looks much to uniform for that [managed to look at a few pics on Rose's but nothing like yours, heres the closest I could find  http://plant-disease.ippc.orst.edu/ShowDisease.aspx?RecordID=876

I still think a deficiency of some sort, maybe even of iron chlorosis. You say the plants are on death watch and you have lost 6 or 7 which is awful news, I am beginning to wonder if there is something wrong below which is affecting above, its wont be  much use adding nutrients if the plant cant take them up.
Did you have a look at the root system of any of the ones that died? did it all look ok?, I know I may be wrong but I am like you struggling for an idea.

[davidwood]

Dave I think this maybe your problem, certainly the leaves look very similar to the first pics you showed.

http://aggie-horticulture.tamu.edu/publications/cucurbitproblemsolver/leaf/beetyellows.html

[roadrunner]

I doubt it's iron chlorosis.  The plants get the iron chelate that HVH sells on a fairly regular basis and the leaf appearance isn't right.  It's the only product I've tried that works well with hard water.  I've also tried Fulmag Magnesium as a soil drench and a foliar spray since this is occuring on older leaves which would indicate a magnesium deficiency. It doesn't have any effect.  I have not lost any plants from this leaf condition.  The loses have been from plants showing the leaf symptoms like the picture in the April 30th post.  That I believe is a secondary infection of some type from a spider mite attack except unlike previous years, I haven't been able to find any spider mites which are not difficult to see.  The possibility of microscopic mites has been discussed with Charlie and Cindy. Even with a lighted loope I haven't been able to find any. The Kontos should be taking care of that if it exists anyway.  It appears to be the typical decline some hibiscus go into after a severe mite attack, so were are the little monsters? The roots?  Not many roots in the pots though the ones that are there don't look bad until the very end. Cindy is working on some ideas about why sick hibiscus frequently don't recover and hopefully she will chime in on this.

dave

[Charlie]

99 percent of the time hibiscus leaf problems will clear up by themselves or with some fiddling with fertilizers or pesticides. However, Dave, your problem is persistent and causing the decline of some plants. What you need is a proper diagnosis since randomly selecting things to try is not working.

An actual diagnosis would start with soil analysis including pH and salinity and continue with leaf tissue analysis that would reveal the nutrients actually absorbed by the plant. It would also include a water sample, with and without the fertilizer(s) you use. Professional growers monitor all these continually so that problems can be seen before they become real problems. There are labs all across the country that will do these analysis for you from samples you send to them via mail or UPS.

If this is too much to do, then I would advise backing off to the very basics. Feed ONLY with HVH Special Blend at the rate of 1/2 teaspoon per gallon, do not spray the leaves with anything but water. Apply Kontos at the rate of 1/4 teaspoon once per week.

Water sufficiently to keep the plants moist with about 10 percent runoff from holes in the pots with every watering except on days the Kontos is applied when no runoff should occur. Then wait and see what happens for 2 months.

Plants that cannot be revived should be discarded in the trash in case the problem is a virus that spreads via aphids, thrips, and whiteflies mostly. Virus diseases cannot be cured and can be spread by leaf piercing insects.

Best of luck!

Charlie

[roadrunner]

Thanks Charlie. Some of those things I'm already doing. I fertilize at a rate of 1/2 tsp per gal with the HVH special blend with the exception of using Houseplant Formula infrequently on the plants that are already distressed. I don't fertilize with every watering. I only use care products offered by HVH with the exception of Safer's Soap which you recommended I discontinue using, so I have done that.  I also spray those with SuperNova a few times per week.  None of the really sick plants are showing the stange leaves any longer. Now they're just small and lack any vigor.  I've separated them from all the other plants and have them located in the house near a south facing window with no direct sunlight.  If any are going to come back it will need to be there.  I recently backed off on the Kontos to once every 10 days at 1/8 tsp per gal.

Note: All of the 29 outside container plants including the ones with the strange leaves got 1.53 inches of rain Sunday and Monday combined. Since they are on the Kontos regime they all sit on saucers. The saucers needed to be drained several times so it would be safe to assume they were flushed significantly.  If our monsoon season continues in earnest the bulk of the watering will be rainwater which should moderate any PH and salinity issues I assume.  I'm finally getting some very vigorous growth on most of them and some nice flowers as well.  The greenhouse plants are where the problem is more significant but I'm even seeing some rebound in plants I thought were gonners.

My plants are growing in Miracle Gro Potting Mix with the addition of perlite, pumice, and earthworm castings.  We don't have much to choose from here.  I've been experimenting with the addition of Supersoil Palm and Cactus mix to the Miracle Gro for my container roses and like the results.  I may try that for the hibiscus as well.

Will any of the lost plants I mentioned previously become available in the store again? Primarily that would be Torch Song and Fantasy Charm, and definitely Cindy's Heart if she doesn't make it.

Thanks,
dave

[Yashodhara]

Hi Dave - You might want to check the N-P-K ratio of the plant food MircleGro added to the potting mix you used... The reason why I point this out is because MircleGro adds A LOT of phosphorus in its N-P-K ratio (nitrogen (N), phosphorus (P), and potassium (K)).  A high phosphorus ratio will prevent your hibiscus from utilizing all the great supplements you are feeding them, as it basically shuts down their nutrient uptake... Remember: Hibiscus LOVE high potassium, LOW phosphorus.  I found this out the hard way with the MiracleGro cactus soil I used for my seedling (all I had at the time) and it had the same yellowing pattern on it's leaves (check out the Forum pictures I posted for 2012 New Hybrids/Seedlings - Arnottianus x Self Seedling).  I switched to Charlie's soil mix (which I add 50/50 to an organic soil mix from my local nursery) and all is well.  

[roadrunner]

Hi Deb,
I checked that ratio before I started using it.  Its ratio is 21-7-14.  Nitrogen is a bit high but the phosphorus to potassium ratio seems ok, probably not ideal but ok.  It appears they don't put much fertilizer in that potting mix and anyway most of the plants were potted up over a year ago and that fertilizer should be long gone by now.  I've been using the Miracle Gro for several years without any problems.   I don't use any fertilizers high in phosphorus on anything I grow which includes loads of roses and daylilies.  I haven't made any major changes in the care program, I started growing these hibiscus in 2004 and have just under 100.  Cheez, I never had spider mites or foliage problems until about 3 years ago, only aphids.  I have added SuperNova and Fulmag Magnesium to the program as well as Kontos for the mites.  These problems are occurring on only a portion of my collection.  Unfortuntely I just can't afford Charlie's mix, I'm a retiree on a modest income and the Kontos is destroying the gardening budget, not to mention a lot of other budgets as well.

I don't think the fertilizer ratio is the problem but maybe they are still getting too much of it. I'll throw in a few more water only days and see how it goes. Currently a large portion of the collection is watered daily. Only a few of the less vigorous growers about every 2 to 3 days.

dave

[Geneva]

Take your plant to your local college agricultural dept and they will likely check it out for you for free. Also you may want to do a google search for 'hibiscus chlorotic ringspot virus' as I think this may be what you are dealing with. Best of luck and let us know how things go for you.

[roadrunner]

Thanks Geneva - Based on google search results, it seems that it is very likey 'hibiscus chlorotic ringspot virus'.  I think it takes running some tests to confirm it.  Don't know if the closest university agriculture dept would be up to the task.  I haven't been able to find any images close to what I'm seeing here but the description of symptoms seems right on.  It appears to be quite variable in appearance.  What I've been thinking was several different leaf symptoms may indeed only be one, although I believe I have some fungus or bacterial leaf spot issues as well.  Unfortunately a good portion of what I've been reading is over my head.



dave

[Cindy]

Dave, your leaves are different from all the ones in the viruses people are posting about, and they are also different from magnesium and iron deficiencies. Your chlorosis is IN THE VEINS, not between the veins. It's definitely chlorosis of some kind, but not the typical chlorosis from pests, viruses, and deficiencies that hit the chlorophyll between the veins. I'm researching, and I'll see what I can find for you. I've been researching viruses for awhile now since so little is known about them in plants, and it isn't one of the ones I've been studying. Give me a few more days and I'll see what I can find for you.

Also the H. chlorotic ringspot virus disfigures flowers badly as well as yellowing the spaces between the veins. Your flowers have been fine when they bloom, haven't they?

Cindy

[Cindy]

Dave, can we get scientific about this? Can you please answer some questions for me?  It's impossible to use an intuitive approach to solving plant problems without some actual measurable data and very clear information.

So, choose the plant you want to observe - we'll call it Plant A. Snap a pic and date it today as our starting point.

Now answer these questions, each one carefully please:

1. How many of those spotted yellow leaves does Plant A have today?
2. How many healthy green leaves? (You can estimate, but please use a number)
3. Where are the yellow leaves? Old growth at the bottom? New growth at the top? All on a single branch? Be very specific please about each yellow spotted leaf.
4. Is there anything else of concern on the plant? Be very specific.
5. What is the state of the soil? Wet, moist, dry?
6. What kind of sunlight is the plant getting? Direct (how many hours?), indirect?

We'll use this for a baseline, and then you'll need to observe Plant A each day and send me the answers to these questions each day, so we can get some data on exactly what is happening. You can send it by email or do it here - whichever you prefer.

Cindy

[roadrunner]

Cindy the flowers are normal.  I have 3 basic leaf problems going on.  I'll pick a representative plant showing each symptom and try to get started asap.  I'll email data and photos to you instead of posting on the forum.

thanks,
dave

[Doll]

Here is a ph chart I found online showing how different nutrients are affected by ph.

[roadrunner]

Thanks John but this is looking more like a viral problem. I've been growing these hibiscus since 2004 and the new problems have started recently only in about 15 percent of my 100 plant collection. Most of my plants are thriving and all receive the same nutrients, water, and are growing in the same potting mix.  I occasionally see iron chlorosis which is quickly corrected with HVH's iron chelate.  This also does not respond to Fulmag magnesium.  This is something different.

I've lost several plants following last summer's major spider mite attack before I got them on Kontos.  Some hibiscus just never recover from a major mite attack and it appears this possible virus is something that was transmitted by the mites.  Several of my plants have struggled and lingered and are finally starting to die from it.  The peculiar thing is that many of the mite attacked plants have recovered nicely.  Some survive it, some just don't. Incredibly frustrating and annoying. 

dave

[Cindy]

As I'm studying the post-spider-mite problem, it's looking less and less like a viral infection to me. The more I read about viruses, the more it seems that they're spread mostly by flying insects. Thrips and whiteflies are the two main hibiscus culprits. Spider mites don't move very far in their lifetimes. In fact, most of their movement from one plant to another comes from either plants directly touching each other, or humans or pets picking them up and carrying them from one plant to another. Spider mites are slow walkers who can't jump across gaps, so simple isolation is the first line of defense against spreading them. The second line of defense is our own body awareness, and being careful not to pick them up on sleeves, hands, gloves, watering tools, pruners, etc. The only way spider mites can spread a virus is if you already have a plant that has a virus, and you allow the spider mites to spread to other plants in your collection. But viruses would not spread rampantly through a collection - they would move only from one plant to an adjacent plant that's touching it. The virus must be picked up from the sap of one plant, and then walked over to another plant that the same spider mite chews on. It's rare for one spider mite to make big moves like this. So the virus theory is look less and less credible as I study more and more. I haven't found a virus that infects hibiscus that is spread through water or from mother to child through DNA or RNA. These viruses don't actually infect the spider mite - they are simply carried by the spider mite's mouth from one leaf to another. Spider mites have such a short lifespan and travel such short distances that this really is not very feasible. A spider mite can live an entire lifetime on a single leaf!

But after lots of reading, observing, and studying the post-spider-mite syndrome, it's looking more and more like a root problem to me, whether mechanical or microbial. My guess is that it's a mechanical problem, due to the diminished capacity of damaged leaves to suck water through the plant. This problem slowly grows worse as water uptake is diminished, and water builds up in the soil since it's not being drawn up into the plant, which starts to drown the most delicate root ends. Then we start to see the leaves wilt a bit more and slowly die from even more lack of water, diminishing water transport even more, leaving more water to sit in the soil and drown more roots... even more diminished water transport... even more standing water in soil... even more of the leaf drop.... a kind of self-perpetuating syndrome where leaves seem to slowly die of thirst and roots seem to slowly die of drowning. If it goes on long enough, you can dig up the root ball and see that it is about 20-30% the size it should be! A root-bound pot will have turned into a tiny little root ball with dark colored roots instead of healthy white roots.

Giving the hibiscus more sunlight to try to force the water transport to work better sometimes helps in the very early stages. But too often it makes the problem worse. Leaves that aren't getting enough water just can't take extra sunlight, and they drop off even more quickly and speed up the vicious circle.

Giving the plant bright shade and extra humidity, with daily misting of the leaves to provide extra moisture, seems to work much better and more consistently. Misting with a solution of Wake Up Spray (1/8-1/4 strength) and Super Nova (full strength) has worked best of all for me, by helping the leaves start growing, and sucking water through the plant a bit more quickly again. If this is started immediately after a spider mite attack, the prognosis is really good - close to 100% recovery. If the plant is almost completely defoliated from spider mites, the prognosis is not as good and recovery takes much longer, but it's still the best thing I've found to try.

It's not just spider-mited hibiscus that this has worked on for me either! I've used it on overwatered African Violets, heat stress and transplant shocked roses, and other garden plants and houseplants that have had severe stress (like puppy attacks!).

Cindy

[roadrunner]

Since spider mites are not the virus vector then the culprit must have been the white flies I had for a good portion of 2010 and 2011 before I started the Kontos treatments. Cindy and I have exchanged emails discussing the loss of leaves and roots and the pots retaining water too long in a revolving downward spiral with the end result the loss of root mass and eventual death of the plant.  I've seen it in my own collection several times and currently have 8 plants in the last stages before their demise which I expect within a few days.  Unfortunately I believe most of these are only infrequently offered in the store and will be difficult to replace.

dave