Gonna try and answer several different questions in one post....
" But then that would wipe out any possibility of hiking or long dog walks all year round, which means that I would be even heavier than I am now"
Snowshoeing, skiing, hitch the dog to a dog sled
"(And for that matter, IS it even legal to sell plants without a nursery license, and can you get one without "them" (TPTB) mandating a regular routine of chemical spraying?"
I think you can ship if the plants are visibly rust free but others here who actually do that and live in the USA can answer better than I can. Daylily rust is no longer a federal quarantine issue but individual states can set their own rules. If this is something you're contemplating, phone your state's plant protection agency and ask.
"I am brand new at daylily and just wonder about rust, is it the worst thing that can happened to daylilies ? When you said sprayed it, if not dish soap what do you recommend using (I don't have rust, but would like to prepare just in case, since it's been raining like crazy here). If not treated what worst can happens to daylily infected ? Will it kill it... "
If you don't mind using "chemicals" then you would ideally rotate two or more fungicides if you got rust. The best ones are very expensive so wait until you get it! If you don't get it badly you may get away with occasionally using a contact insecticide. You don't have to do anything, you can just try to ignore it. It should not kill the plants but if they have it year round (does your foliage die back in winter?) it could weaken the plant and make it vulnerable to other problems, at least in theory. Avoid watering the plants late in the day if you can, so that they're not wet overnight, and don't space them close together such that it impedes air circulation.
"Is thrips and aphids are the worst ? I notice that some stuff on the leaves, firstI thought it was just dirts or pollen fell into my daililies leaves (Kwanzo has been growing pretty big leaves) and today I saw a some kind of white stuff and my Lilies look damaged from bugs too, so I sprayed them with Insect Killer Spray.."
I don't know that it's easy to say which is worst. Aphids proliferate quickly and are slurping up the plant's sap and therefore nutrients which is obviously not a good thing. Thrips don't build up to such numbers but they do damage flowers. Their leaf damage isn't particularly significant unless you get them a lot worse there than I do here. Not sure what the white stuff might be, unless it's shed aphid skins. Does it look like this (bottom picture):
http://www.daylilies.org/ahs_d...
Do you still have the "pollen" on the leaves? That sounds more like it could be rust, if it's not actually pollen. If it is rust it will still be there so can you post a picture?
"What should I do to avoid/treat this problem (bugs)..."
There's no one-size fits all other than growing the plants as well as you can, avoiding over-fertilizing etc. because high nitrogen encourages certain pests. Otherwise the treatment needs to be tailored to the specific problem. Most soft-bodied insects can be controlled with insecticidal soap. Aphids can be difficult because they get down into the leaf bases which is why people often use a systemic insecticide. Thrips are also difficult because they get in crevices, inside buds etc. where a contact spray won't get them. But you don't have to kill every bug that you see, you can let nature's beneficials take care of them unless they become intolerable (and yes, I know for many people one bug is intolerable
)
"stumped at the moment is that *something* seems to have attacked one particular pot of one particular daylily. "
Any chance of a picture?
"I am seeing leaf streak on some plants that I have not seen it on before - again maybe thanks to our wet winter. I think we may have touched on this before... whether there was any connection between rust resistance and leaf streak resistance, but I can't remember if there was any consensus or conclusion. We should maybe have a line in the database for leaf streak status (resistant, susceptible), just as for rust."
There are other things that can look like leaf streak. but to answer the question there isn't necessarily a connection between resistance to one disease and resistance to another. Some daylilies are even susceptible to one strain of daylily rust but not to other strains to same degree. Where resistance is primarily genetic a plant is going to be resistant to whatever it has resistance genes for. For a disease that "likes" weakened plants then it may be susceptible to anything opportunistic if in that state. Leaf streak most likely needs an injury from something else before it can infect the plant, rust can go for any genetically susceptible plant including perfectly healthy ones. There is such a thing as systemic acquired resistance but I don't know how that might work with resistance related to specific genes. With rusts, for example, avoiding high nitrogen and ensuring adequate potassium are nutritional steps one can take towards reducing the problem. Some other plant diseases are favoured by low nitrogen, high pH, low pH, etc. etc.
