The majority of hosta problems are Anthracnose, nematodes and HVX and other viruses. Not necessarily in that order.
Anthracnose can be diagnosed with brown spots / streaks and cancer like spots. This can be effectively treated with a fungicide.
Nematodes can be detected by tearing a leaf and placing it in a clear glass dish for 10 minutes to 1/2 hour. Backlighting the dish will show nematodes, if they are there. The treatment is to either remove the infected plant and all others within 6 feet...or wait until February and dig up the roots and place them in 130 degree tap water in the kitchen sink for 10 minutes and pot the plant up and replant in August. Nematodes do not live in soil (they only "swim" through it and hybernate in it) so no problem putting anything back in the same spot after this regimine. Another alternative is to do a lot of spraying to kill them, but it will take a long time and a lot of diligence as spraying will not kill the eggs. Or some people just live with them. I think I would go with the continuous spraying first and "cooking" if that wasn't effective. "Living with them" is not appealing to me.

Failing the observations / tests for Anthracnose and nematodes you probably have a virus. Looking at pictures of viruses will confirm.

Treatment would be as follows:

Spray with insecticide to prevent spread of non-HVX viruses which can be transmitted by insects.

Viruses are all terminal and the next thing to do is paint the hosta leaves with glyphosate to kill the tissue which is necessary for virus survival. I would wait until Spring to remove the hosta as it may take a month or more for the roots to die completely. Instinctively digging the infected plant out while it is alive is the very worst approach. It can immediately spread the virus or any remnants of the root or crown in the soil can and will spread the disease to any plant that has a cut or torn leaf or root. If the hosta are not sprayed then the virus can be spread with insects and killing the hosta will cause the insects to simply migrate to other host hostas.

In the Spring, dig out the remains of the dead, virus sterile roots and plant more hostas or something else.

I think this is simpler and surely less expensive than even a simple HVX test whenever something looks unusual. It also gives an indication of what category of problem you are facing and gives treatment alternatives that, in many cases, are safer and more effective.

When you have a virus-

SPRAY

KILL

WAIT

Jon

Les, you were talking about pictures for a file, weren't you? Links to them? And not the actual treatment for hosta ailments, just photos that identified a problem if it showed up in the leaf?

Then I'm no help there. Access to photos will have to be mostly through links, unless the copyright holders submit them as they do for Hosta Library. Additionally, with the photos should be discussion of what the image reveals. I can look at a picture all day and not see the problem which the pros can say, "Oh, that is tobacco mosaic," instant recognition.

Your file is a great idea and the beginning of a data base which can be manipulated and organized while it is small so one day it will be broadly helpful with leaf problems. But is there another similar source that does what you are envisioning? hmmmmmm, I have no idea. Sorry, no help here.

I read somewhere when hosta leaves get burned by sun or injured somehow, fungus or virus present around the garden can take over from there and will make it look worse. Only a few hostas in my garden look perfect at this time of the year. I will pull the leaves off after they have dried after frosts, place them in the garbage and that is it, no panic here.
Bernd

Bernd: you are right. This is a terrible year to view problems with hosta leaves. When I was trying to ID Bobbi's I'd been willing to swear her NOID BHN22 was virused. Steve insisted it wasn't. ken ID'd it and now that the 2nd growth is appearing I am no nonger concerned about HVX. It ia just 'Janet' being Janet. I'd learned.

moc-thanks for redirecting my post back to where it is intended to go. I don't understand why jon went where he did, and hope not to open up an arguemen. I want to try to develop a photo-file to show leaf problems, not how to eliminate diseased hostas. The purpose is to determine "if" and "when", not "how", to get rid of "BUGGED" hostas.

Les

Bernd,

The problem with wait and see is that non-HVX viruses can be transmitted by thrips and nematodes. I would not argue with your decision if not sure, but in the case of an infected hosta, you are lucky if it is HVX as it cannot propogate except by actual sap transfer.

Other viruses can spread far more readily and the longer these infected hosta are in your garden, the greater the risk. These can cause far more damage, far more quickly.

If you are unsure you could post a picture here and I'm sure there would be a few that would volunteer their opinion. You could then evaluate which opinion you may feel comfortable with and then either act according to suggestions or not. Wait and see could be a very dangerous choice.

Jon

Nematodes do not live in soil (they only "swim" through it and hybernate in it) so no problem putting anything back in the same spot after this regimine.

Jon, not sure I agree with your advice here. As you say, nematodes overwinter in soil and once it warms up they'll be looking for dormant buds and beyond that petioles, as I discovered the hard way.

Myself, I would never plant anything back in an area where I'd found a plant with foliar nematode infection. The very least I'd do is dig out an area roughly double the size of the rootball of the plant in question -your 6 foot area is sensible- and fill the hole with boiling water. Even then there is no guarantee as I discovered this summer when I spotted nematodes in a 'Hanky Panky' I had transplanted next to the area I had a 'Maui Buttercups' with nematodes last year. Obviously the area I dug out was not large enough and this year I'll take slightly more drastic steps. I'll be removing the top 18 inches or so of the entire raised planter I discovered this in. The planter box has to be rebuilt - it now is red cedar that is infested with and destroyed by carpenter ants. I'll using some form of decorative cement blocks, lined with plastic to keep leachate out of the soil.

Pieter

Maybe I didn't do a good job of asking my question. I am interested in links to websites where our forum members can SEE pictures of deformed looking hosta leaves and what caused them to be "Funny Looking". Then we will be quicker to zero in on problems if we see them in our hostas.

An example is "GO TO HOSTA LIBRARY" where there is a section for HVX infected hostas. Or "ACME (a roadrunner company for our cartoon buffs) Hostas has a really good section with a lot of good pictures showing hosta diseases in their web-site." (Hint: don't go looking for ACME Hostas: it's in my "BEEP-BEEP" >>>>>>>>>>>> imagination with Wiley Coyote as the hostaholic. - LOL)

Les

Pieter,

Nematodes do travel through wet soil and hibernate in soil. They do need plant tissue to live. This is why I suggest that when hostas are determined to have a virus that "nematacides" be used in conjuction with killing the plant (removing the required source of food).

Perhaps a better way to approach the problem would be to perform the nematode testing to determine whether they are evident first. In many cases Nematode damage is readily determined by characteristic elongated brown streaks. If there is no nematode infection then using an insecticide would still be a good idea as it would be difficult to determine the thrip or other insect population and spraying would be "cheap insurance" to prevent transmission to other plants.

In any event a combination of a non-HVX virus with nematode or thrip infection would be a difficult situation.

I think these are the only practical ways to approach the problem. Extensive and expensive laboratory testing may or may not determine the virus or other disease involved, but that still leaves the problem of treating it when the plant is in a bed which you are trying to preserve.

I don't know of any other prudent next step other than killing the plant, in situ, and ensuring it is completely dead. Killing it before taking steps to address nematode or thrips first or concurrently will speed up the spread as we know that nematodes or thrips live on tissue and killing / removing the plant alone will simply cause them to go elsewhere.

If the action where taken with ground freezing immenent, then your suggested scenario of hybernating nematodes infecting new plantings may be possible. I think this would be a very unusual and improbable situation as hostas would be dying off before any real ground freezing.

There are no over-the counter approved nematacides, however cholinesterase, the ingredient in Bayer Systemic is listed as a nematacide and might work as well as anything available to the homeowner. Of course bleach and ammonia will kill them undiluted, but the problem of how much to use and preventing damage to neighboring plants is a big problem. Spraying with a 10% solution of ammonia is done for slug control, so this might be an option to help. I simply don't know of any sure-fire nematode control other than professional treatment.

Jon

Pieter,

...and, of course your method of boiling water will work as well.

Jon

As I discovered the hard way, Jon, only when you dig a wide enough hole....too bad, so sad, still dealing with the aftermath of not being quite agressive enough...

Pieter

Pieter,

I imagine that unless you have a very big pot of boiling water it probably doesn't have very broad coverage. Compost is said to inhibit nematodes, or Neem oil, sesame oil and even sugar.

Since the temperature needed to kill nematodes is 145 degrees F (63 degrees celcius) it may be easier to hook a garden hose up to the hot water faucet from the washer in one's cellar (or wherever) and use that rather than boiling water. The "hot" setting on a heater should be close to 150 degrees F. It will certainly give a larger supply of water.

It is a tough one. Some recommend a trench around the area to be treated and covering it with clear plastic to cook nematodes over a summer season. Hopefully nematacides in the works will become available to homeowners shortly and give an easier way to address the problem. No current approach seems easy except professional treatment which can be very expensive.

I think a systemic application, perhaps coupled with a diluted (10:1) ammonia spray occassionally would help keep them at bay. Ammonia kills slugs too, so it might "Kill two birds with one stone" Well tilled organic soil with good compost content is said to produce enzimes that kill them as well. That certainly can't hurt.

Jon

Thamks for the suggestion, Jon. I have an on-demand -Navien- tankless hot water that I can easily dial up to that temperature, but I don't think I'll bother. The area involved is a raised planter with a depth of about 20" and an overal size of perhaps 8-10 sqft. The planter will be replaced with something that's imperveous to carpenter ants, which will require the removal of most of the soil anyway. It's not difficult at that point to replace the bulk of it with some other soil and a healthy dose of compost. All the hostas in there will be potted up this weekend and kept isolated for the next couple of years with the 'Hanky Panky' that now shows nems getting a bleach bath in the spring when it's nosing up. I've had good success in the past with bleaching nematode infested hostas.

Pieter

Pieter

I have used the bleach cure for Iris borers; dunking them in 100% bleach and then into a water bucket to rinse. It worked great. 100% success.

No experience with bleaching hostas. Thankfully I have not needed to try it...but would not hesitate.

Jon

Jon, I had the misfortune of noticing a nematode infection in several plants I received in trade in '07. I have detailed those trials and tribulations on my website, see link below. I won't hesitate to do this again.

Pieter

Here is a link that might be useful: My experience with foliar nematodes

Bye

Les

Piet,

Very interesting and informative. The remedy I found for Iris borer suggested a 10% concentration for a longer soak as with your procedure. As an alternative an undiluted soak in bleach for 15 seconds followed by a clear water rinse was given. It sounds as if the same procedure works for hostas based on your family's experience and it sounds like an easier, maybe surer method than heat treating.

Thanks for the helpful information and background.

Jon