Creeping Jenny (Lysimachia) has brown spots and is dying

(Question)

I am caring for creeping jenny used as a ground cover, and there is a portion thats dying, the stems are mostly still green, but the leaves are all brown, shriveled and crispy. I included a picture but i have others closer up. I want to know why its dying and how to fix it please. I live in toronto, its a bit dry now but there is rain and i water when its needed, nothing spilled/was sprayed on it and it gets pretty much full sun. Is there not enough water, even though the rest is fine? Theres a white fungus/ mould but i see it on healthy stuff, is that how it starts? Im baffled and it seems to be spreading slowly so id like to stop it before it all dies. Any help would be welcome, thanks!

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(Answer)

Creeping Jenny (Lysimachia nummularia) can be affected by Rhizoctonia Crown and Stem Rot and Southern Blight (Sclerotium rolfsii) as well as other fungal diseases.

The symptoms of these fungal problems in ornamental plants are brown spots on leaves, brown edges, brown stems and eventual die back of the entire plant. Small brown nodules of fungus can be seen at the base of the plant if you look closely or with a magnifying glass. Other plants in the Lysmachia family are prone to the fungal diseases as well.

The fungus is difficult to eradicate as it is in the soil and spreads with mycelium and spores. Keeping a tidy garden, picking up infected leaves, and cultivating the soil can help keep the fungus at bay. Cutting the plants entirely down or removing them to get rid of infecting spores can also be done. The fungal infection can worsen and the plants can become an eyesore or so badly infected they partially die. It is best to remove them, excavate the infected soil, replace it with new high quality sterilized soil, and choose new plants not likely to be infected with the fungus.  Be sure to wash all tools and wheelbarrows when finished.

The list of plants likely to be susceptible to these fungal problems are:

Ajuga–bugleweed
Anemone–windflower
Aquilegia–columbine
Arrhenatherum–oat grass
Asplenium–dragontail fern
Caladium–fancy-leaved
caladium
Campanula–bellflower
Chrysogonum–goldenstar
Convallaria–lily-of-thevalley
Dicentra–bleeding heart
Digitalis–foxglove
Dryopteris–wood fern
Hemerocallis–daylily
Hosta–plantain lily, hosta
Lysimachia–loosestrife
Phlox–phlox
Ranunculus–buttercup
Vinca–periwinkle
Viola–violet, pansy