On 8/27/2016 2:35 PM, karaman wrote:
hallo,
my lilac is about 4 years old, had 4 super scented flowers in spring.
now the leaves at the top turned brown and dropped off, trundling on
towards the lower branches which still have some leaves hanging on in
there..... have noticed some tiny white spots on the branch. what is
wrong i dont want to lose her! what shall i do?

As other posters have noted, the first thing to assume is a moisture
problem. Another possibility is verticillium wilt. It usually does not
affect the entire bush or tree, just a section, usually the topmost or
outermost stems or branches first. The leaves initially stay green but
wilt, and then turn brown. The stems usually die, but sometimes will
resprout the following year.

There isn't anything one can do about verticillium wilt, except give
the shrub or tree some extra care to minimize stress, since stress can
make the wilt worse.

I've had this for many years with my thirty-plus year old Japanese
tree lilac. I'll usually see a small stem or two wilt/brown/die back
each year, but every few years the dieback will be more substantial -
a entire branch or three. But given plenty of water during hot/dry
spells and a biennial fertilizing, despite the wilt, the tree thrives.