Q. Today I found this frond on the ground and it looks like a fungus on the back of it. Can our palms be saved with treatment?
A. From my perspective, there are two options. The first is to recognize that white fuzz on leaf fronds of many of palms is normal. It depends on which palm it is.
My first reaction in seeing the picture you sent was that it was normal and this was one of the palms with fuzz exactly where it is in your picture.
The second option is that it is a disease or insect problem that I have not seen before. We do have mealybugs and scale insects that cause a similar white fuzzy appearance. This normally occurs on palms growing indoors, not outdoors.
I still tend to think that this is a palm with normal white fuzzies on the leaves. What is troubling is that you told me one of your palms died. If the palm is well-suited to our desert climate, death would be rare.
So I went searching for diseases that might give the same appearance as white fuzzies on the leaves. I could not find any.
Many people assume that palm trees are low in water use. They are not. Palms survive very nicely in the desert near an oasis where they can drink freely from available water. They don't survive in the middle of a desert landscape with a minimum amount of water.
A telltale sign that they are not getting enough water is poor development of the fronds. They may be smaller than normal and scorched around the margins of the leaves. Eventually the bud in the center of the palm dies thus killing the entire palm.
Palms can be weakened if they are not receiving enough water, if they go through a very hard winter which stresses the central Bud, if they are severely pruned to look like a feather duster in late fall or if new palms are planted in the fall instead of spring and summer.
My gut tells me that your palm frond with the white fuzzies is one of the normal palms (you can check this by looking at other fronds on the same plant and see if they are fuzzy as well) and that your one palm which died was weakened and the central bud was killed by bud rot.