Disease on Red Trumpet Vine
Last year I noticed withering leaves and graying flowers. I couldn't decide if it was a fungal or insect problem. I pruned well and sprayed with fungicide. A month later it seemed the same so I sprayed with an
insecticide. Now that it is about to bloom the same problem exists. What to do??
This doesn't sound like insect damage. You might want to consider taking samples of both the leaves and blooms/buds to your area agricultural extension service office for advice.