Odd Growth on Dragon Fruit Plant

[sildanani]

Lately, I have noticed an odd rusty looking growth on my two year old dragon fruit cactus. It sits near a palm tree that has sorta similar looking spots. Could the spots from the palm spread to the cactus If it came in contact with it? I don't have a great photo of the spots on the palm. (It's a bit blurry.)
Also, I have been spraying all of my plants with a solution of water and dish soap up before this had popped up to keep the bugs off. Any suggestions?

[phantomcrab]

Have you been spraying the cactus while it was in the sun? It could be sunburn from water droplets focusing sunlight on the skin. It is generally not a good idea to spray any chemicals (or soapy water) on a plant while in full sun.

[sildanani]

Have you been spraying the cactus while it was in the sun? It could be sunburn from water droplets focusing sunlight on the skin. It is generally not a good idea to spray any chemicals (or soapy water) on a plant while in full sun.

Thanks phantomcrab! That totally makes sense. I never thought of that. I'll not longer be spraying that plant since its in full light.