Hello,
I have an indoor avocado tree. Its around 4 years old, about 8ft tall. So far its been reasonably healthy, a few brown tips but nothing significant. However, over the last few weeks leaves on lower branches are turning black. This usually starts with the the leaf veins becoming a bright, contrasting yellow. Then the areas around the veins turn brown, then black, and then the leaf falls.
At the moment its only a few older leaves but I've noticed the process has begun on the newer healthy leaves as well which makes me worry its a more serious problem. The stem is also turning black in places. I recently moved it to a sunnier window and so I suspected it might be sunburn, but I'm now wondering if its related to the leaf problem.
If any one has any tips on whether this is a pest/ nutrient/ watering problem then I'd really appreciate it.
Many thanks in advance!