Having a problem with my lilac trees

Question

I have planted lilac trees two years ago and they where doing great. There 4 times the size now. One is the normal one you see around and the othere one is a bush lilac. Parts of leaves started to turn a light green and then start to change brown. After this the whole lilac turns brown and it dead?? I lost two lilacs already and now the bush lilac is turn and so is the last lilac tree. There is know white spots on the leaves so I'm thinking is not a fungus. What could be doing this?

Thanks

Answer 1

The list is long.  You need to take samples of the leaves and stems (I'm thinking lilac ash borer for insect, several problems for soil or nutrients, root problems, etc)  to a good nursery or you Cooperative Extension Service in your county.  The agent is an advanced degreed agronomist or horticulturist who if they don't know can sent it to the state experts.  

White spots could be powdery mildew, downy mildew but it would have to be super severe to be causing twig death.  

Lighter leaves could be nutrient deficiency, salt problems, water problems.

Also herbicide problems.....have weed killers been used in the area?  

and the list goes on.  You need to have some expert eyes on those plants.  

Answer 2

It sounds l there is a parasite effecting these trees or bushes.

you should go onto a gardening site in your area and see what you can do to salvage at least some of the bushes.

good luck.

Answer 3

The one with white spots probably is powdery mildew.  It has been particularly bad in areas in which there has been high humidity and a lot of moisture. There are other lilac diseases as well.   The other plants may indeed be dead possibly from Alternaria but you may want to wait a few weeks to see if they leaf out again. If you are not adverse to treating with a fungicide then do it but be aware that treating with a fungicide does carry a certain risk to you and it sounds like you have a lot of plants to treat..  Even if you decide to spray be sure to get up every leaf that falls off the sick plants now and during the winter because the fungus will stick around over winter on the old leaves.  Burn them. You really shouldn't compost them because then they could stick around to infect other plants.   One other thing is that you may want to check out what cultivars you are buying. Many of the plants that come from places like Walmart (not to pick on them or anything but they just buy whatever is cheapest when it comes to plants) may not be the best plants.  Make sure it is a cultivar that is resistant to Powdery mildew if you decide to replant.