I'm not sure what is going on, but exceptionally wet and hot weather can result in petiole rot or southern blight. Move the mulch back away from the base of the plants at least 6 inches and see if you notice any little orange balls, white mycelium or any other form of rot.

Steve

This post was edited by steve_mass on Fri, Jul 5, 13 at 15:40

The first one looks like foliar nematodes. I don't think you have southern blight as the stems would be falling over or pulling out easily. The oldest leaves might have a little rot problem (the ones that are going yellow).

Once you have nematodes in the garden there isn't a whole heck of a lot you can do as there aren't any really good permanent controls for it. If it wasn't so wet you might not even have seen them.

If they have the nems and are in the ground, I have no advice. If they have nems and are in a container, you can try a 30 minute bleach soak with 10-20 % bleach (mix 1 part bleach or 2 parts bleach to 10 parts water), then pot them up in new soil, new pot. I did that early last year to three hosta which came from the same nursery, and all were set back to small sizes, but this spring have shown growth clean of the nems.

But the real booger for us southern gardeners, which strikes quickly and fatally, is the southern blight, southern rot, anything you wish to call it. From looking beautiful one day to being a limp mass of rotted stems with the little orange balls around the base of the plant....like tiny Osmocote fertilizer pellets........only takes maybe 24 hours, and its a goner.
Time to trash the plant.

I had it happen this last week to Totally Twisted. I have watched for this everywhere, since it seems to be triggered by extreme sweltering heat with no breezes to circulate the air. Then the rain and high humidity. I began moving my potted hosta apart, giving more air space between them. Poor little Totally Twisted had been stuck between three larger pots, and I feel the air stagnated and it was ideal for the blight.

I found my mama plantaginea with the little balls growing around her base, and I moved her to the hot direct sunlight. Some mention was made of heating the soil to 117 degrees to kill the mycellia, which was present in her soil. But I want to save HER, and I'll toss the soil. Perhaps washing the roots and the bleach soak could help with blight as well as nematodes.

Blight affects vegetable garden plants such as peppers and tomatos, so it is not specific to hosta. It is spread on your shoes (like Mad Cow disease in that respect), on your tools, on garden waste not removed. Dig out the dirt in that hole in the ground, pour boiling water over the hole (do not know how much it takes to do any good), get RID of the old soil. Watch about your shoes! (I love my 4 identical pair of garden clogs cause they wash in the machine so easily.)

Too much rain is serious if there is not enough drainage. We have rain all day today, more predicted tomorrow. I will be cruising through the hosta pots myself, keeping an eye on pots with the first signs of the blight. All afflicted hosta must be isolated quickly (containers make it easy to do this) and kept from contaminating the others, while you try to work some magic to save your favorites.

The temps are down now to 75 in Mobile, so we don't have a high temp to deal with. Just a lot of rain. Hope you can keep the blight under control up in Georgia.