How do I treat? The back of leaves have a round, white, web formation that spreads quickly and kills the leaf. It's on various plants in the yard" canna lily leaves, chitalpa tree leaves, giant bird of paradise, miniature tangerine tree. The chitalpa tree is nearly dead!! LD
Disease on a Tree and Some Plants
Certified GKH Gardening Expert
I know just the thing. This is my recipe for a broad range of insects, fungus, and other pests. It is safe for the plants, animals, and people in the area, and you can use it at any time as often as you wish. You may skip the soil priming, but it is always good to do just to make sure the soil is clean, and performing at its best. If you do not have all of the ingredients for the spray, it will still work. The more you have the better, and more effective it is. The recipe is as follows:
First, you will want to prime the soil with dolomitic lime, then spread wettable sulfur to Kill off any infection in the soil. I Also like to spray the plant itself. Mix a few drops of one or more of these ingredients into warm water with a spoonful of coconut oil: Rosemary oil, lavender oil, neem oil, garlic oil, cinnamon extract/oil and for really bad cases, also add clove oil.
Here is an article with other good remedies:https://www.gardeningknowhow.com/special/organic/natural-home-pesticides-organic-garden-pest-control.htm