Q.desert rose leaves turn brown on tips and die
was repotted last year
One of the most common problems is stem root and leaf disease. Stem rot occurs on the tips of the adenium desert rose plants and progresses down the stem. Leaf rot occurs in adeniums when the leaf is continually wet.
Fist, leaf rot in adeniums is the easiest to treat. Just remove the effective leafs on he desert rose plant and move the location of the adenium so the leaves dry out. When you water try not to wet the leaves or if your plants are watered using sprinklers make sure you do it early in the day so the leaves have time to dry out quickly. Do not water adeniums in the evenings.
Desert rose plant stem root is caused by a fungus. It’s the most common problem with adeniums. The adenium rot is either black, dark drown or yellow. The actual desert rose rot part can be wet or dry and it processes down the stem of the adenium. When we see this we do not wait for he plant to fight the problem we cut the effective part off the plant. When cutting off the stem make sure you look inside the stem and make sure the adenium plant cut is far enough down so you only see good tissue with discoloration. Adeniums may stop this rot by forming a abscission zone.
https://www.gardeningknowhow.com/ornamental/flowers/desert-rose/caring-for-desert-rose-plants.htm