New Gardener Need Help with unknown Disease on Fruit Trees

[mikeThePlanter]

We have a question regarding the fungus, disease, or something that attacked our Apple tree, which we think might be dead (see pics). It now appears to have spread to the Lemon and Pear tree which are about 6 feet away. And its spreading quickly. I want to save the new young 2 yr pear tree and the lemon tree (approx 5 yr old) produces about 80 lemons a year. It seems to attack leaves and stems. It makes the leafs curl up, turns them brown and then black. It also has some white with the black. It looks like some mold or fungus but not sure.

How can I find out what this disease/fungus is and what to do to treat it? I'm hoping someone has seen this before and can help diagnose.

We live in Burbank, California. Not sure if the disease came when we bought the apple tree last year or if it spread from neighbors.

Any help would be appreciated. Full size images are on my dropbox. Attaching them to the post.

1-4 = aus_3670 to aus_3680 = lemon tree leaves showing disease

lemon tree leaves

lemon tree leaves

lemon tree leaves

lemon tree leaves

5-7 = aus_3681 to aus_3685 = apple tree looking dead

apple tree

new apple branch question?

apple tree whole shot

8-9 = aus_3686 to aus_3688 = pear tree 1 leaf looking infected

pear tree dead leaf

https://www.dropbox.com/sh/db7n7i2d1ltu ... xz8ga?dl=0

Thanks,
Mike The Planter

[applestar]

I can't help with the citrus -- hopefully someone else can.

The pear -- I want to scroll down and see the rest of the tag! What cultivar is it? The shriveled leaf cluster looks suspiciously like fireblight, and the other leaf tip with black edge may be showing signs too. Disinfect a pruner and cut off the shriveled cluster close to the trunk. If you see brown in the cut sub bark layer instead of clean white, you might be in trouble. Spray some rubbing alcohol on the cut anyway (and disinfect the pruners again). Fireblight is bacterial and hard to cure -- only remedy I have heard of is an antibiotic treatment... Usually you just cut away affected branches, but you can't if it gets in the main trunk -- it's better to buy a resistant cultivar. If it's not and fireblight is prevalent in your area, and this is a new tree, you may want to return it if you can.

Apple tree -- I do NOT see the graft union (bump on the trunk) on your tree. Did you bury it too deep? The shoot growing from the base is likely a sucker from the root stock and will need to be cut off at the base. Upper branches -- test for deadness by flicking the branch with your nail -- does it feel light, sound dry and hollow? Then try bending it -- if it snaps then it's dead, if it flexes, then it's alive. If the pear has fireblight, the apple could too. Again, resistant cultivar is the best defense for least amount of spraying with chemicals (and minimum need for organic sprays).