Possible root-knot nematode?

[ViolaAnn]

My 'Patriot has not done well for the last couple of years. It's 11 years old and had always done well until last year. I moved it in autumn 2012 to a location next to 'Loyalist' because it looked better there, but otherwise it seemed happy. Someone told me last year, that 'Patriot' was doing poorly all across the regions; so I waited and hoped it would be better this year but it wasn't.

Today I dug it, intending to pot it for the rest of the season, but I think I'm seeing nodes or knots on the roots and wonder if I should be trashing the plant instead. And if it is root-knots, what should I do with that part of the garden? The soil is heavier than in some parts of my garden. I'm sitting on heavy grey clay and there used to be a tree near there; so it's one part of my garden that had not been improved as much as some others, though I've added compost.

Anyway, here are pictures.

Looking good in 2015 - July 3

July 13, 2016

July 1, 2017

The first root picture taken today. Look at the under side of the eye to the left of the photo.

[ViolaAnn]

More root pictures taken today.

Look near the centre of the picture.

[Chris_W]

I don't see any sign of root knot nematodes, but the hosta has fusarium root and crown rot. There is really no saving it so I would trash it and start over. You should dig up the soil around that spot to get as much of the old roots as possible and put some fresh soil or compost in its place, but know that fusarium is a naturally occurring fungus and you will never really get rid of it. Keep that area very well watered to help prevent it from getting out of control as fusarium multiplies the most in dry soil conditions and then enters through a cut or wound in the plant. When hostas dry out too much they are more susceptible to getting it.

[ViolaAnn]

I guess it's a good chance to get rid of some of the heavy soil there and replace with lighter stuff with a lot of compost. I guess maybe our extremely dry summer last year might have contributed to it. Thanks, Chris.

[ViolaAnn]

Chris, am I likely to have problems with the adjacent hostas? So far they all look fine, but they aren't very far apart. Should I apply some type of fungicide? (I think we can still get some).

[Chris_W]

Keep them well watered and that will help. They say that fungicide drenches aren't really effective against fusarium in the soil. If you have other hostas close by then don't cut into them when changing some of the soil. Just try to scoop out as much of the rotten roots as possible, even if that is simply scooping it out by hand.

[ViolaAnn]

Well at least keeping them watered isn't a problem this year. In May we had more than double the usual amount of rain and may more than normal in June as well. Today was the first lovely, rain-free day we've seen in a loooong time.