| Whats the problem with the phlox or the pic? I'll attempt to ansew both. note the daylilly to the right of the pic it's blocking alot of air that any phlox needs this air will help prevent the fungus bulid up on the leaves. As well the leaves got to wet to often and wiht out preventive measures. The phlox flowers are just coming to end sad but true they tend to do that this time of year. 1 they need to get the best air on the phlox as possible by either removing the daylilly or/and replanting the phlox where it is best suited ( my choise is bye bye daylily ) 2 they need to split the phlox up into two/three parts in early spring when the new leaf growth is two three inches out of ground and provide it with the very best air they can give it ( see why I would take the daylily out now it too is going to be twice to 3 even 5 times bigger next season too)a big soil sucker if ever there was one too. 3 After they decide to move the daylily or the split up phlox to a new home and proper home they need to concider that both of them do a fine job of finding there own water if they still feel a need to water they may do so in very small amounts at the base of the phlox ( the daylily can take watering leaves any time )IE drip line or trickles for short times if they have an irrigation system with pop up heads the wind will still carry an overspay to the phlox last problem is the rain none of us can stop that.
4 The dicolored leafage is a fungus formed by getting to wet for two long from any manner mentioned and a lack of air ( we already discussed air and water) leaving it down to rain and a complete lack of prevention or control measures for the fungus spots on leaves I think we got it down to rain now: An organic product both pesticide and fungus control goes by the name of K-Neem
I prefferane this product and purchace it as a concentrate and use it in a pump and spay bottle for best resuls with getting under leaves as well in a time frame of every 7 - 10 days where 7 days means rain in the past seven or rain coming on the next it is very effetive with labled instructions followed:
Premix ready to use is found in most stores near the indoor plants and cut flowers area at a cost of 8-10 $ for a 32 once bottle ( it will be difficult to get this to spray under side of leaves ) concentrate is found at a good garden center with a price range of 23-30 $ this will make a few bottles perhaps lasting three years of 32 once pump and spay bottles get one there very good pick a new color if you have one alreay. (guess who doesnt sell for less now LOL )best price worms way webb site and phone orders
Read the label and follow the insructions save some real cash in comparison hands down and be kind to bees don't use any pest or fungus control if bees are active in a garden area at any time Good luck with your garden fanny it has been a pleasure to help you today. Phlox pest None Phlox attractions Hummingbirds, Butterflies and a bee every now and then Easy grower with right sun and air requiring splitting on a bi annual to three year time frame and fungus controling measures Daylilly pest: none Attratctions: None fragerance: none colorings: Many
I label this a set it and forget it plant and use it as a fence along a poorly sunlight area with a semi hostil soil for weed control which it does do well.In a nut shell this thing can grow anywhere with out any form of care does require divison on a semi annual basis the site I have mine in did slow it down on division but one day it will all get burnt including the ground where they sit | 
