Sooty Canker?

I'm wondering, is it gradually becoming black, getting worse or did it appear to get this appearance suddenly?

Winged bug is an adult antlion.

Splitting bark is a bad sign as is oozing sap and along with the discoloration could be due to sun scald or other stress. Did you have the tree pruned in the last year? Pruning too much or at the wrong time of year can expose previously shaded bark to the burning rays of the sun.

Another possibility is water stress. Ash trees are water hogs and would prefer to be next to a stream or river. Be sure you are soaking your tree's root zone once a week during the summer tapering to once a month in winter. The amount to apply will depend on the size of your tree. As an example, an ash with a canopy 10 feet wide will need 84 gallons of water a week. (Appendix J, Guidelines for Landscape Drip Irrigation Systems).

Apply water at the drip line and not next to the trunk - that's where the feeder roots are located.

For now, you can loosely wrap your tree's trunk with burlap, cardboard or commercial tree wrap (comes on a roll and looks like wrinkled brown craft paper). Or you could paint your tree's trunk with latex paint dilutted 1:1 with water. Any color is OK.

Good luck.

I agree. The sun can do big damage to tree trunks in this climate.

Thanks for all the replies. The condition is on the south side of the tree and getting worse. The house had a renter during the last year so I have not been paying attention on a weekly basis. :( This tree has not been pruned in 2 years. It is rather small is size for 8 years old. The canopy is probably 10' across. The tree stands around 10' high. I do know it's planted directly on top of caleche (sp?). The other ash tree that was about 25' away died from root rot due to water not soaking in.

This tree is located next to a large Bermuda grass area. I can see the roots did move south into the Bermuda, probably chasing more water. I will adjust the # of heads and gph to increase the water volume.

I saw that someone recommended wrapping the trunk. Is the wrap done tight or loose?

Any additional thoughts would be greatly appreciated!

Trees need water to soak down 2 - 3 feet into the soil and sprinkler water won't do that. That's why it can be hard to water trees in turf. Grass only needs water down to 6 inches or so which creates the surface tree roots you see. If you can use a hose and let it trickle overnight at the drip line (edge of branches) of the tree. At night the water won't get as hot in the hose as during the day.

Wrap loosely. You need air circulation next to the trunk.