scorch, oak wilt or ?

Dynawriter · 21st September 2010, 08:14 AM

I have four trees (some type of red oak) with problems. I'd appreciate any suggestions about potential treatments or if there's even a need to treat them. (This part of Austin, Texas, has lots of oak wilt, but I've prophylactically treated all the trees with Mauget's Tebuject microinjections biennially for several years.)

Trees # 1: Some smallish red oaks are mostly healthy but their problem is increasing steadily. See picture.

scorch, oak wilt or ?-small-oaks-szd.jpg

Tree # 2: This big red oak has a relatively small number of leaves with the discoloration pattern shown in the picture. Leaves start dying at the distal edges ,and death moves toward the base of the stem.

scorch, oak wilt or ?-big-bedroom-oak-szd.jpg

Tree # 3: This red oak with seven trunks became mostly dead within a couple of months this summer. Four trunks have some stains like the (biggest) one pictured. The stains don't smell.
This may be the tree where I saw numerous insects (about the size of red oak borers I've seen in pictures) on the trunk in early evening in early July. I didn't see any obvious bore holes yesterday.
Leaves haven't dropped after dying. On four of seven trunks, a relatively small number of leaves are still alive. They're mostly newer leaves on smaller trunks.
When I microinjected the trunks in early July, I had to move a few feet up some trunks before I found live wood to inject. The tree looked fine at that time.

scorch, oak wilt or ?-trunk-stain-improved-szd.jpg

Tree # 4: Forty feet away is another large red oak (or some tree in that family) that became mostly dead within a couple of months this summer. Dead leaves haven't dropped. One area has leaves with this pattern. See leaves in the picture's four corners.

scorch, oak wilt or ?-leaves-translucent-szd.jpg

Thanks in advance for your help.

TreeSpecialist · 21st September 2010, 10:02 PM

Quote:

Originally Posted by Dynawriter

I have four trees (some type of red oak) with problems.
Your trees are generically called "Sapnish oaks" or "texas red oaks." (Quercus texana)

I'd appreciate any suggestions about potential treatments or if there's even a need to treat them. (This part of Austin, Texas, has lots of oak wilt, but I've prophylactically treated all the trees with Mauget's Tebuject microinjections biennially for several years.)

The excessive heat (August - drought) followed by the recent rains have created a plethora of funngal leaf problems.

Treating with Tebuject® without seeing symptoms on or near the trees is (in my opinion) a waste of money. A good product, but you need to actually have oak wilt symptoms near by to have the need to treat.

Trees # 1: Some smallish red oaks are mostly healthy but their problem is increasing steadily. See picture.
Attachment 16911

I don't see anything in this picture worth treating. The leaves will fall shortly as fall approaches and the leaf problems will disappear with the leaves. Treatment would be a) pointless, b) an unnecessary expense and c) do exactly nothing to the leaves appearance.

Tree # 2: This big red oak has a relatively small number of leaves with the discoloration pattern shown in the picture. Leaves start dying at the distal edges ,and death moves toward the base of the stem.
Attachment 16912

This is typical of drought stressed leaves as they senesce.

Tree # 3: This red oak with seven trunks became mostly dead within a couple of months this summer. Four trunks have some stains like the (biggest) one pictured. The stains don't smell.

The bleeding cankers are caused by phtopthora. Most dry up by themselves. I've seen a great many this year in Austin,

This may be the tree where I saw numerous insects (about the size of red oak borers I've seen in pictures) on the trunk in early evening in early July. I didn't see any obvious bore holes yesterday.

The longhorn borers are most common and attack trees in stress. They are an indicator of stress rather than a problem in and of themselves. These borers don't attack healthy trees. Solve the stress problems and the borers will leave the tree alone.

Leaves haven't dropped after dying. On four of seven trunks, a relatively small number of leaves are still alive. They're mostly newer leaves on smaller trunks.

When a tree dies in mid season, the leaves don't go through the normal chemical changes. Abscisic acids are not formed and the leaves are retained for 12 to 18 months.

With most of the tree being dead, the remainder will likely follow.

When I microinjected the trunks in early July, I had to move a few feet up some trunks before I found live wood to inject. The tree looked fine at that time.
Attachment 16913

Injecting needlessly in red oaks unnecessarily wounds the tree. Multiple injections may have killed a significant amount of tissue.

Tree # 4: Forty feet away is another large red oak (or some tree in that family) that became mostly dead within a couple of months this summer. Dead leaves haven't dropped. One area has leaves with this pattern. See leaves in the picture's four corners.
Attachment 16910

The picture resembles Western Travis County. Tens of thousands of red oaks have died or are dying as a result of the 2 year drought Austin is coming out of right now.

Thanks in advance for your help.

Pat Wentworth
Austin Tree Specialists - Tree Services Austin - Austin Arborist

TreeSpecialist · 21st September 2010, 10:08 PM

#1 The excessive heat (August - drought) followed by the recent rains have created a plethora of funngal leaf problems.

Treating with Tebuject® without seeing symptoms on or near the trees is (in my opinion) a waste of money. A good product, but you need to actually have oak wilt symptoms near by to have the need to treat.

I don't see anything in this picture worth treating. The leaves will fall shortly as fall approaches and the leaf problems will disappear with the leaves. Treatment would be a) pointless, b) an unnecessary expense and c) do exactly nothing to the leaves appearance.

#2 This is typical of drought stressed leaves as they senesce.

#3 The bleeding cankers are caused by phtopthora. Most dry up by themselves. I've seen a great many this year in Austin,

This may be the tree where I saw numerous insects (about the size of red oak borers I've seen in pictures) on the trunk in early evening in early July. I didn't see any obvious bore holes yesterday.

The longhorn borers are most common and attack trees in stress. They are an indicator of stress rather than a problem in and of themselves. These borers don't attack healthy trees. Solve the stress problems and the borers will leave the tree alone.

Leaves haven't dropped after dying. On four of seven trunks, a relatively small number of leaves are still alive. They're mostly newer leaves on smaller trunks.

When a tree dies in mid season, the leaves don't go through the normal chemical changes. Abscisic acids are not formed and the leaves are retained for 12 to 18 months.

With most of the tree being dead, the remainder will likely follow.

Injecting needlessly in red oaks unnecessarily wounds the tree. Multiple injections may have killed a significant amount of tissue.

#4 The picture resembles Western Travis County. Tens of thousands of red oaks have died or are dying as a result of the 2 year drought Austin is coming out of right now.

Pat Wentworth
Austin Tree Specialists - Tree Services Austin - Austin Arborist

Dynawriter · 22nd September 2010, 09:05 AM

Thanks very much for the info, Pat. Your reputation as a font of knowledge remains intact.

For several years, there has been oak wilt nearby in red and live oaks. Do I need to get a diagnosis on the almost-dead red oaks (pictures 3 & 4) in case it's oak wilt and I need to remove them before fungal-mat season? The seven-trunk oak already has at least one small fungal mat that's white, not the dark color of oak-wilt fungi.
I've been unsuccessfully trying to contact the county forester for two weeks to see if it is oak wilt; so I can then get some monetary assistance to remove them. I know he's swamped, but I wonder if the assistance program is out of money?

TreeSpecialist · 22nd September 2010, 09:47 PM

Quote:

Originally Posted by Dynawriter

Thanks very much for the info, Pat. Your reputation as a font of knowledge remains intact.

For several years, there has been oak wilt nearby in red and live oaks. Do I need to get a diagnosis on the almost-dead red oaks (pictures 3 & 4) in case it's oak wilt and I need to remove them before fungal-mat season? The seven-trunk oak already has at least one small fungal mat that's white, not the dark color of oak-wilt fungi.
I've been unsuccessfully trying to contact the county forester for two weeks to see if it is oak wilt; so I can then get some monetary assistance to remove them. I know he's swamped, but I wonder if the assistance program is out of money?

Diagnose red oak trees? Wouldn't be a bad idea although it's not likely to be oak wilt.

Fungal mat season?

Varies from year to year. Hard to pin down a "season."

White vs dark fungal mat?

White would likely indicate either a lichen or perhaps another saprophyte.

"Dark fungal mat" of oak wilt?

Very seldom seen. Usually the pressure pad of the "fungal mat" is below the bark and all that is seen on the outside is a weeping of a dark sticky fluid.

Not to be confused with other bleeding cankers that many think to be oak wilt when it is not.

County forester/ monetary assistance?

Unlikely. You must first have a positive diagnosis for oak wilt with active fungal mats on red oaks - then cost share might run as high as 40% for cost of removal - cost share only kicks in after the money has been spent up front.

With the multiple 100º days this summer and the very dry August, I wouldn't expect any red oaks dying from oak wilt to have survived with enough moisture to produce a fungal mat this fall.

The likelihood of your trees having oak wilt is close to zero.

If you're in Westlake, you need a permit to have the trees worked on or removed. Don't touch the trees without one - the penalties are stiff.

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21st September 2010, 08:14 AM	#1
Dynawriter I'm new here so be nice Join Date: Sep 2010 Location: Austin, TX Posts: 2	scorch, oak wilt or ? I have four trees (some type of red oak) with problems. I'd appreciate any suggestions about potential treatments or if there's even a need to treat them. (This part of Austin, Texas, has lots of oak wilt, but I've prophylactically treated all the trees with Mauget's Tebuject microinjections biennially for several years.) Trees # 1: Some smallish red oaks are mostly healthy but their problem is increasing steadily. See picture. Tree # 2: This big red oak has a relatively small number of leaves with the discoloration pattern shown in the picture. Leaves start dying at the distal edges ,and death moves toward the base of the stem. Tree # 3: This red oak with seven trunks became mostly dead within a couple of months this summer. Four trunks have some stains like the (biggest) one pictured. The stains don't smell. This may be the tree where I saw numerous insects (about the size of red oak borers I've seen in pictures) on the trunk in early evening in early July. I didn't see any obvious bore holes yesterday. Leaves haven't dropped after dying. On four of seven trunks, a relatively small number of leaves are still alive. They're mostly newer leaves on smaller trunks. When I microinjected the trunks in early July, I had to move a few feet up some trunks before I found live wood to inject. The tree looked fine at that time. Tree # 4: Forty feet away is another large red oak (or some tree in that family) that became mostly dead within a couple of months this summer. Dead leaves haven't dropped. One area has leaves with this pattern. See leaves in the picture's four corners. Thanks in advance for your help.

21st September 2010, 10:08 PM	#3
TreeSpecialist Mature tree Join Date: Mar 2008 Location: Austin, Texas Posts: 373	Re: scorch, oak wilt or ? #1 The excessive heat (August - drought) followed by the recent rains have created a plethora of funngal leaf problems. Treating with Tebuject® without seeing symptoms on or near the trees is (in my opinion) a waste of money. A good product, but you need to actually have oak wilt symptoms near by to have the need to treat. I don't see anything in this picture worth treating. The leaves will fall shortly as fall approaches and the leaf problems will disappear with the leaves. Treatment would be a) pointless, b) an unnecessary expense and c) do exactly nothing to the leaves appearance. #2 This is typical of drought stressed leaves as they senesce. #3 The bleeding cankers are caused by phtopthora. Most dry up by themselves. I've seen a great many this year in Austin, This may be the tree where I saw numerous insects (about the size of red oak borers I've seen in pictures) on the trunk in early evening in early July. I didn't see any obvious bore holes yesterday. The longhorn borers are most common and attack trees in stress. They are an indicator of stress rather than a problem in and of themselves. These borers don't attack healthy trees. Solve the stress problems and the borers will leave the tree alone. Leaves haven't dropped after dying. On four of seven trunks, a relatively small number of leaves are still alive. They're mostly newer leaves on smaller trunks. When a tree dies in mid season, the leaves don't go through the normal chemical changes. Abscisic acids are not formed and the leaves are retained for 12 to 18 months. With most of the tree being dead, the remainder will likely follow. Injecting needlessly in red oaks unnecessarily wounds the tree. Multiple injections may have killed a significant amount of tissue. #4 The picture resembles Western Travis County. Tens of thousands of red oaks have died or are dying as a result of the 2 year drought Austin is coming out of right now. Pat Wentworth Austin Tree Specialists - Tree Services Austin - Austin Arborist __________________

22nd September 2010, 09:05 AM	#4
Dynawriter I'm new here so be nice Join Date: Sep 2010 Location: Austin, TX Posts: 2	Re: scorch, oak wilt or ? Thanks very much for the info, Pat. Your reputation as a font of knowledge remains intact. For several years, there has been oak wilt nearby in red and live oaks. Do I need to get a diagnosis on the almost-dead red oaks (pictures 3 & 4) in case it's oak wilt and I need to remove them before fungal-mat season? The seven-trunk oak already has at least one small fungal mat that's white, not the dark color of oak-wilt fungi. I've been unsuccessfully trying to contact the county forester for two weeks to see if it is oak wilt; so I can then get some monetary assistance to remove them. I know he's swamped, but I wonder if the assistance program is out of money?