I have these in ground plumeria that took a bad turn very recently. I noticed a pretty quick change from normal to mottled yellowing, new growth leaf curling, misshapen leaves, and found a moderate infestation of white fly. These plants have been healthy for 7-8 years, always deep dark green foliage usually until October.

I'm just wondering if the white fly (or other unseen pest) would cause this large amount of leaf discoloration.

I have other in ground plumeria on my property which don't have any signs of bugs or leaf discoloration.

I fertilize (I use liquinox 10-10-5, superthrive, kelp, and fish fert) about once a month and the watering is done by hand once a week. I do the watering by hand since I killed a few from using the sprinklers over the years, I'm pretty sure these ones are not getting too much water.

I'm going to try neem oil in a sprayer for the white fly, but such a large area to cover I'm worried I won't get perfect coverage. I can barely get underneath these plants. I did remove all of the heavily infested leaves, and did a water blast as best I could to get many leaves clean.

I'm looking for opinions if this could be a nutrient or soil problem in addition to the white fly or just the insect problem. I hate to see these plants suffer if there is a change I can make. This is zone 10(A) in California.

Any ideas? Thanks for your time.